4

Respiratory Protection for the Public

The COVID-19 pandemic and the recent widespread wildfires in the United States have lent new urgency to the public’s interest in and need for having appropriate and effective respiratory protection. As described previously, however, regulatory processes for respiratory protective devices have historically been limited to occupational use scenarios, so that there is no structure in place for ensuring that the respiratory protection needs of the public are met. This chapter examines experiences with the use of respirators, medical masks, and face coverings outside of occupational settings to mitigate inhalation hazards; the challenges that impede application of the occupational model to the public; and the need for an organizational and regulatory framework for addressing current gaps in processes for oversight of and guidance on respiratory protection for use by the public.

This chapter serves as a complement to Chapter 3, which examines respiratory protection for workers whose employment settings fall within the purview of a federal regulatory agency (e.g., the Occupational Safety and Health Administration [OSHA]) and are therefore covered by respiratory protection programs (RPPs), as well as workers who are not currently covered by such programs but may face inhalation hazards. Chapter 3 also provides evidence and lessons learned from the occupational context that are applicable to the general population. Together, Chapters 3 and 4 are foundational for the committee’s recommended approach to addressing the needs of the two target populations for this study—workers not covered by an RPP and the public.

NEEDS OF THE PUBLIC FOR RESPIRATORY PROTECTION

There are diverse circumstances in which the public might require respiratory protection. For example, consider the following three scenarios:

• It is March 12, 2020. An individual wakes up in Scranton, Pennsylvania, to learn that a day earlier, the World Health Organization (WHO) had declared that COVID-19 was a pandemic (WHO, 2021).
• On the evening of August 16, 2020, while driving home from work, an individual in Monterey, California, learns of dangerously high levels of smoke from raging fires in Pine Canyon and River Road, east of Salinas, about 20 miles away (CAL FIRE, 2020).
• An individual returning to home after a major flooding event finds significant mold growth requiring remediation (Riggs et al., 2008).

Beyond such emergency-related scenarios, the public may require respiratory protective devices in more routine aspects of daily life, such as while engaged in home maintenance or hobby-related activities that result in exposure to inhalation hazards. Many factors may affect the decision making of members of the public on the selection and use of respiratory protective devices, including their knowledge, skills, attitudes, and beliefs. In their decision-making process, members of the public may seek answers to such questions as those listed in Box 4-1 (framed as a user’s practical questions on selecting, procuring, and safely and effectively using a respiratory protective device). Yet, because no single body or a group of coordinated entities has developed evidence-based answers to all of these questions, members of the public currently face substantial barriers to making informed decisions on when to use a respiratory protective device, what device to use, and how that device should be used for effective protection from specific hazards for their families and themselves. For many people, the cost of a device may be a further consideration, potentially limiting access. Misinformation, conflicting recommendations from different authorities, misleading product claims in advertisements, and counterfeit products add to the challenges faced by the public in determining whether to use a respiratory protective device and what device to select. In the face of such confusion, members of the public may choose such alternatives as staying indoors or leaving the affected area. However, those steps may be insufficient, leading to avoidable morbidity and even premature mortality. The following three sections explore in more detail the needs of the public with regard to device types, use, safety, and access.

CURRENT DEVICES FOR THE PUBLIC AND NEEDS FOR FUTURE RESPIRATORY PROTECTIVE DEVICES

Landscape of Devices Available to the Public

Faced with a perceived need for respiratory protection, the public will seek to learn which devices are identified by authoritative sources as appropriate for use in their particular circumstances. However, credible and trustworthy guidance on the selection and use of devices for protection from such inhalation hazards as SARS-CoV-2, wildfire smoke, mold, and ambient air pollution is currently lacking. This unmet need for trusted guidance is exemplified by the ongoing COVID-19 pandemic. At times, the public has been confused by guidance regarding the level of personal protection, particularly against infectious airborne particles, provided by different devices (Clapp et al., 2020). This section briefly describes the landscape of devices that have been used by the public with the intent of reducing exposure to inhalation hazards during past public health emergencies as well as devices that have emerged in the market during the COVID-19 pandemic. These devices range from respirators, to surgical masks, to cloth face coverings, and also to newly emerging technologies. An overview of these various devices and their purposes is presented in Chapter 1; detailed information regarding factors that influence their performance (e.g., filtration efficiency, fit) can be found in Appendix B.

Respirators

A variety of respirator models are on the market in the United States, including elastomeric facepiece respirators and filtering facepiece respirators (FFRs). These devices are not intended or marketed for routine public use, however, because the full protection afforded by respirators, including N95 FFRs, is ensured only if the user undergoes fit testing and is trained to use and care properly for the respirator. Also, FFRs generally are not evaluated for facial fit as part of the National Institute for Occupational Safety and Health (NIOSH) respirator approval process, except in cases of a novel design (CDC, 2018). Given that FFRs are the primary form of respirator used by members of the public, who, unlike workers in RPPs, will likely not undergo fit testing, ensuring proper fit is a notable issue to be addressed for nonoccupational use of such devices.

Despite the lack of fit-testing requirements analogous to those designed to ensure appropriate protection in an occupational setting (discussed in more detail below), N95 FFRs have been deployed for public use during prior public health emergencies. For example, local governments and charitable organizations in the United States and Australia have provided

N95 FFRs to the public during wildfire smoke events (Morain, 2020; Sacramento City Express, 2018).

While FFRs have been designed for use in an occupational setting, two 3M respirators—the 3M^™ particulate respirators 8612F and 8670F—were cleared by the Food and Drug Administration (FDA) in 2008 for use by the public during public health emergencies caused by an outbreak of an airborne infectious disease. These respirators were briefly made available to the public during the H1N1 influenza pandemic in 2009–2010 (McCullough, 2021), but because of a lack of demand for the devices following the H1N1 pandemic, 3M discontinued their manufacture and sale in 2013 (3M, 2021).

Medical/Surgical Masks¹

A simple search for surgical masks on Amazon in March 2021 yielded 100 “best sellers” with varying descriptions and prices. However, the public does not have authenticated information with which to make an informed decision among such offerings, including whether any of them could be considered a respiratory protective device offering some level of respiratory protection. Rather, the decision to buy a particular product is often driven by price and consumer ratings, which tend to reflect bias on the part of the individuals submitting the reviews (Amazon, 2021). Medical/surgical masks may also be supplied to users by governments and charitable organizations following a natural disaster or other public health emergency (Galea et al., 2018).

Cloth and Other Face Coverings

Also available to the public are a number of commercially marketed face coverings made of different types of fabrics and with varying designs (e.g., materials, structures, closure mechanisms, and finishes). The manufacturers of some such products claim that they provide protection and comfort for the wearer based on their filtration efficiencies, antimicrobial properties, and moisture management treatments.² Notably, however, data are lacking on the safety of chemical treatments used on some face coverings for antimicrobial and moisture management purposes. Such factors as the propensity of the chemical finish to leach, off-gas, or be ingested (if the

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¹ As discussed in Chapter 1, the terms medical mask and surgical mask may be used interchangeably.

² The committee did not test or verify any of these claims, as doing so was beyond the scope of this study.

tongue touches the mask during use) could influence the safety of masks with such finishes (Pullangott et al., 2021).

Leakage is a persistent problem with face coverings because of loose fit for some users. Data also are limited on the protection offered by face coverings relative to surgical or medical masks, further impeding the public’s evidence-based decision making in selecting a device. A new class of face coverings, known as barrier face coverings, which comply with the ASTM F3502-21 standard (see Chapter 2) and provide a measured degree of particulate filtration and better fit (compared with other face coverings), is now available to the public.

Needs of Users in the Public for Respiratory Protective Devices

User needs for respiratory protective devices and how they influence the selection of a device are briefly described below. Factors related to performance, comfort, usability, and availability are discussed in more detail in Appendix B.

Is Comfortable and Aesthetically Pleasing

Users want a respiratory protective device that is comfortable (or is not perceived as uncomfortable), and some may select a more comfortable device over one that is more effective if they perceive that the more comfortable device provides adequate protection (Galea et al., 2018).

A major factor in a device’s comfort is its breathability: a device that is breathable is less likely to substantially impact the physiological responses of the user during long periods of use (Roberge et al., 2010). Perceived and actual impacts on the ease of breathing and related changes in heat and humidity felt during use of a respiratory protective device—including feelings of suffocation, stickiness, and sweating—are frequently noted in the literature as a major cause of discomfort among members of the public (Al Naam et al., 2021; Chao, 2020a; Cheok et al., 2021; Ferng et al., 2011). Itching can contribute to discomfort as well (Szepietowski et al., 2020). Device designs should not cause discomfort, pain, or irritation for the user, which may discourage use (Al Naam et al., 2021).

Beyond comfort, aesthetics may influence selection and use of a respiratory protective device. There is a social dimension to how individuals feel about wearing such a device and how they are perceived by others, which in turn may affect decisions on use (Al Naam et al., 2021; Allison et al., 2010).

Does Not Impair Vision or Communication

Because a respiratory protective device may be used for long periods of time, it should not impair the wearer’s vision or communication, as such impairment may prompt the wearer to remove the device. In particular, fogging of glasses associated with use of a respirator, mask, or face covering (Al Naam et al., 2021; Chao et al., 2020b) has been reported as a barrier to use (Labiris et al., 2021). Additionally, several studies report issues with communication among members of the public using respiratory protective devices, including challenges with speaking and recognizing faces and facial expressions that could lead to misinterpretation of the wearer’s intentions or otherwise impede interpersonal communication (Al Naam et al., 2021; Allison et al., 2010; Carragher and Hancock, 2020; Cheok et al., 2021; Freud et al., 2020; Saunders et al., 2021).

Includes Clear Labeling and Instructions for Use

Unclear, insufficient, or misleading labeling of and instructions for use of devices may contribute to improper selection and use by the public (CDC, 2021a; Plana et al., 2021). Current labeling, packaging, and instructions for respirators are produced with the assumption that their users will be covered by an RPP or will be voluntary users with an understanding of the risks involved in their work and proper respirator use. The online information provided to supplement the sales packaging of the devices also targets more sophisticated users, often assuming a level of knowledge that is not realistic except for trained workers within an RPP or those with experience in respiratory protection (NIOSH, 2003). With members of the public now using respirators outside of RPPs and occupational settings, labeling, packaging, and supplemental materials need to be reevaluated to ensure that they are accessible to all users. Changes can be made to improve labeling, packaging, inserts, and online educational materials to help users determine whether a device will address the hazard of concern, provide clarity on the device’s limitations, and explain how to use the device properly to ensure the expected level of protection.

Ideally, respiratory protective devices could be used effectively absent instructional materials. As this is not the case, manufacturers of all respiratory protective devices would benefit from consulting with experts in health communications and health literacy in order to restructure information provided to users—such as clear indicators of the limitations of device use and instructions for donning and doffing—in a clear and accessible way. Consideration should also be given as to how educational materials can be provided to multiple users. Providing informational inserts with each device in a multipack or a QR code for digital resources may be helpful when

multiple users are accessing respirators from a multipack. Also beneficial would be some means of indicating to users that devices meet expected levels of performance and of reducing the risk of purchasing counterfeit products. For example, a standard label system could be implemented (e.g., the NIOSH approval label) to ensure that labels are clearly visible to the user both on the packaging and on the device itself, and that basic information is provided on all external packaging (e.g., manufacturer name, model number, certification category, efficiency ratings, and QR code for digital resources).

Consistent minimum guidelines are needed across manufacturers regarding what information should be included on all labels, packaging, and instructions for respiratory protective devices. Such consistency in information across manufacturers would enhance users’ ability to interpret and understand differences among devices and models and make appropriate selections.

Is Reusable, Stable, and Durable

Ideally, a respiratory protective device intended for use by the public should be easy to decontaminate at home and reuse, depending on the conditions of reuse and user preferences (CDC, 2020a). Reusable devices should have dimensional stability (i.e., retain their shape and size) after multiple uses so they continue to fit properly and remain effective over their intended lifespan.

Current FFR models offer the wearer no clear indication—such as a color change indicator or other such visual cue—as to when the device has reached the end of its functional lifespan. Given that FFRs are designed and manufactured to be disposable, users need to know when to stop using them because the filter medium or seal can no longer provide the intended level of protection. When a respirator is used as part of an RPP in an occupational setting, the RPP limits its use to performance of a specific task or a specific time period to ensure that the device is not used beyond its lifespan and continues to provide the intended level of protection. These limits are normally written into work policies and procedures. RPPs also ensure that wearers of FFRs are trained in assessing the device’s quality and its capability to continue providing the intended level of protection (CDC, 2020b).

In the occupational setting, diminished breathability and/or filtration efficiency (e.g., as the device becomes laden with dust) and its contribution to total inward leakage and reduction of protection are key factors in determining when an FFR should be replaced. However, these factors may be less relevant for the public. When respirators are used by the public, they may be donned and doffed multiple times or worn for prolonged periods of time in low-concentration environments, similar to circumstances in the health

care environment during the COVID-19 pandemic. In these circumstances, loss of elasticity in the FFR straps may be more salient than breathability or filtration efficiency as indicators of when the device has exceeded its lifespan. When the elasticity of the straps begins to fail, the fit of a device may not be as tight as during prior uses, and total inward leakage may increase, resulting in a reduced level of protection (Schumm et al., 2021). Thus, any FFR or other such respiratory protective device designed for use by the public outside of an RPP would benefit from inclusion of clear instructions on how to evaluate the device to ensure that it is still functioning as intended.

When emergency extended use and reuse of respirators become warranted in an occupational setting, an RPP’s policies and procedures can be adjusted to provide education and training to ensure proper use of the devices. However, the respirator use patterns of the public differ from those of workers within an RPP. Extended use and reuse of respirators by the public need to be anticipated even when not recommended for occupational settings. Therefore, educational materials on FFR use by the public need to address safe and effective reuse and highlight the most likely failure points for the devices (e.g., the condition of straps/harnesses). An alternative or parallel approach would be for manufacturers to redesign FFRs specifically with extended use and reuse in mind—for example, by providing more durable or replaceable elastic straps or strengthening strap attachment points.

Respiratory protective devices and other forms of personal protective equipment (PPE) can become contaminated from the workplace environment where they are used. Respirators have been carefully evaluated over the years with this issue in mind, and procedures have been developed for removing the contamination (e.g., radioactive material) so they can be reused safely (RSA, 2001). In the health care environment, the significance of fomite³ contamination has been recognized and addressed for many types of PPE by making the items disposable. During the COVID-19 pandemic, when supplies of respirators and other PPE were scarce and products were frequently reused, the significance of viral fomite contamination became a major issue. A National Academies report addressed the topic of reuse of N95 FFRs in health care settings during an influenza pandemic (IOM, 2006), recommending that research be conducted to understand likely contamination avenues and decontamination methods. While some research in this area has been conducted since that report was published (Chughtai et al., 2019; Fischer et al., 2020), the significance of fomite contamination in a nonclinical setting requires further evaluation so guidance on proper use and care of devices can be provided to the public.

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³ Fomites are surfaces or other objects that may become contaminated with a hazardous agent (e.g., infectious virus) and serve as a mechanism for transmitting the agent to a person or other susceptible organism.

Innovation in Respiratory Protection Technology to Meet User Needs

Innovation in the design and manufacturing of respiratory protective devices has been accelerated notably in response to the shortages and user-experienced limitations of devices during the COVID-19 pandemic, offering promise for the emergence of more effective and user-accepted devices. For example, a new class of respiratory protective devices utilizing artificial intelligence (AI), three-dimensional (3D) image scanning, and 3D printing is emerging in the marketplace, and these devices may address challenges of ensuring adequate fit for a heterogeneous population (discussed later in this chapter) by enabling the creation of a bespoke device from an individual’s facial measurements (Ishack and Liptner, 2021). Other innovations to address fit issues include attempts to minimize leakage at the face seal through the development of braces that fit over a fabric face covering (Fix the Mask, 2021); curved filter designs (Sheth, 2020); and flexible materials, such as those used in continuous positive airway pressure (CPAP) masks, that fit comfortably against the face (Envo Mask, 2021).

Still other innovations are intended to address user needs for respirators that enable better communication. Clear respirator models, for example (CleanSpace, 2021; Ford, 2021), allow people to communicate better with each other relative to conventional face coverings, masks, and respirators and enable those with hearing impairments to read lips. Additionally, concerns related to the exhalation valves on respiratory protective devices during the COVID-19 pandemic have led to the development and approval of elastomeric facepiece respirators without these valves (AIHA, 2020).

The federal government has a role in supporting private-sector investment in innovation. In 2021, NIOSH and the Biomedical Advanced Research and Development Authority (BARDA) launched the Mask Innovation Challenge: Building Tomorrow’s Mask to accelerate the development of the next generation of respiratory protective devices.⁴ Goals for the products developed through the challenge include

• improving the comfort, usability, and protection achieved when worn by the public in real-world circumstances when physical distancing is not possible,
• enabling users of the products to put them on and wear them appropriately with simple user instructions and in the absence of extensive fitting procedures, and
• designing devices capable of being mass produced with a low cost per use.

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⁴ For more information about the Mask Innovation Challenge, see https://www.challenge.gov/challenge/mask-innovation-challenge (accessed August 13, 2021).

Summary and Synthesis

Many different types of devices have been available to and used by the public for a range of inhalation hazards. The landscape of devices used by the public with the intent of reducing exposure to inhalation hazards includes NIOSH-approved respirators; medical masks designed for workplace use, some of which are cleared by FDA; respirators marketed as approved in other countries (e.g., KN95); and products that are not intended to be used as respiratory protective devices in the workplace and thus are currently subject to no certifying body or formal oversight designed to ensure that the devices are effective for their intended use (e.g., face coverings). The efficacy of these products as used by the public is not established. With the COVID-19 pandemic acting as a catalyst for innovation, manufacturers have rapidly responded with devices for the public featuring new constructions and materials designed to enhance fit and wearability. However, the lack of a regulatory framework makes it difficult to understand the level of protection provided by any such product against a known or unknown inhalation hazard. It is unclear, moreover, whether the demand for innovation and the interest of manufacturers in pursuing the development of devices designed to meet the needs of the public will continue as the COVID-19 pandemic wanes.

AVAILABILITY AND ACCESS ISSUES FOR RESPIRATORY PROTECTIVE DEVICES FOR THE PUBLIC

The selection and use of appropriate respiratory protective devices by members of the public depend on the availability of the devices on the market and the ability to access them. Availability and access for the public are limited by multiple factors, however, including a complex, demand-based supply chain, reliance on foreign manufacturing, and inequitable distribution and affordability of devices in times of public health emergencies (Aburto et al., 2010). As discussed in Chapter 2, the COVID-19 pandemic has exposed the inadequacy of the current supply chain and the Strategic National Stockpile with regard to respiratory protective devices. Issues related to device availability and access for the public are laid out briefly in the sections that follow, building on the supply chain discussion in Chapter 2.

Commercial Market During the COVID-19 Pandemic

Several useful lessons around availability of and access to respiratory protective devices for members of the public have been learned from the COVID-19 pandemic. During the early months of the pandemic, supply chain failures and the prioritization of available N95 FFRs for health care workers left the public largely on its own for respiratory protection. In March 2020, FDA issued an emergency use authorization (EUA) permitting the importation and use of non-NIOSH-approved respirators that met certain international standards. With N95 FFRs largely unavailable to the public, imported respirators, such as KN95s, which are certified in China (Andrews et al., 2021), flooded the consumer market, which was plagued by counterfeits and misrepresentations of filtration efficacy (see Box 4-2). The Centers for Disease Control and Prevention (CDC) responded to the influx of foreign respirators in April 2020 by publishing a list of respirators authorized under the EUA. No performance testing data were required from respirator manufacturers to corroborate performance claims before devices were included on this list (Sinha, 2021). In October 2020, FDA announced it would no longer review manufacturers’ requests for their products to be added to the list of authorized respirators (FDA, 2020). According to the

agency’s announcement, KN95s were largely being unused by health care facilities, and the supply of NIOSH-approved N95 FFRs was catching up to demand at the time.

Throughout the COVID-19 pandemic, CDC has emphasized face coverings as source control for the public. As discussed previously, these face coverings were not intended to protect the wearer from infection but to slow the spread of disease in the population. CDC continued to recommended that N95 FFRs be reserved for health care workers even 1 year into the pandemic, when the supply of these respirators had begun to catch up to demand; mention of respirators was added to CDC’s guidance for the public in September 2021 (CDC, 2021d). The agency’s recommendations to the public on use of face coverings and disposable medical masks led to a consumer landscape overflowing with options (e.g., homemade cotton face coverings, commercial fashion face coverings, KN95s) offering unknown effectiveness for both source control and respiratory protection (Fonseca, 2020; Godoy, 2020). Recognizing this chaotic landscape for consumer products, in February 2021 ASTM⁵ issued a voluntary standard laying out design and performance specifications for barrier face coverings (ASTM, 2021a). The standard was intended to provide a level playing field for demonstration of product claims and to reduce the general confusion related to device effectiveness. As discussed in Chapter 2, ASTM’s standard specification establishes minimum requirements for design, performance (testing), labeling, user instructions, reporting and classification of performance properties, and conformity assessment⁶ for barrier face coverings.

Equity of Access to Respiratory Protection

Because equity issues related to respiratory protection have not been adequately characterized, this section includes some lessons learned about these issues with respect to general emergency preparedness. The committee stresses that equity considerations need to be taken into account in communicating about respiratory protection, as discussed later in this chapter. Socioeconomic indicators are linked to equity in disaster preparedness. Within a population, disaster preparedness is predicted by an individual’s financial capacity, poverty status, and education level (Fothergill and Peek, 2004). Those with greater financial capacity to prepare for a disaster are more likely do to so (Boon, 2013), while those with fewer economic means

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⁵ ASTM International is a standards development organization that works through a consensus process involving relevant and interested stakeholder organizations (e.g., governmental, industry, nonprofit). The National Personal Protective Technology Laboratory (NPPTL) deputy director cochaired the ASTM committee that issued the barrier face covering standard.

⁶ Conformity assessment is a process used to determine whether a device meets certain standards or requirements relating to its safety or quality.

and resources tend to invest less in preventing and mitigating adverse effects of natural hazards and environmental hazards (Hallegatte et al., 2017).

While studies examining the link between socioeconomic status (SES) and disaster preparedness are generally focused on property improvements and disaster insurance, SES likely also plays a role in the public’s ability to secure respiratory protection. The lack of standardization in sizing (discussed later in this chapter) means that consumers may need the means to purchase multiple different brands or styles of respiratory protective devices before finding one that fits adequately. Consumers wishing to access such devices must have the means to either travel to a point-of-sale location or place an online order, both of which may be limited by SES. Those wishing to make an in-person purchase for respiratory protective devices are limited by their transportation options. Individuals who do not live within walking distance to a point-of-sale location need accessible, efficient, affordable, and safe transportation alternatives (Malekafzali, 2009).

Online ordering is not necessarily an option for those with limited transportation options. Online ordering is less prevalent among households with lower income levels; those that are small in size or have a single member; those with less access to electronic devices; those with older members; those whose members have lower education levels, do not commute by automobile or work from home, or are non-White; and those in rural areas (Figliozzi and Unnikrishnan, 2021). According to the 2017 National Household Travel Survey, respondents in households above the poverty level were almost twice as likely to make online purchases compared with those in households below the poverty level (61 percent versus 33 percent). Broadband availability also affects online shopping habits and reflects some of the urban vs. rural online ordering trends. According to the 2016 American Community Survey’s 1-year estimates, 83 percent of urban households had broadband subscriptions, compared with 76 percent of rural households (FHWA, 2018).

Social determinants of health⁷ may also play into the likelihood of receiving assistance during a disaster, in the form of both direct assistance and information dissemination. For example, even a year into the COVID-19 pandemic, underresourced communities, such as American Indian and Alaska Native tribes and nations, including the Tohono O’odham and Navajo Nations, found it difficult to secure PPE and other infection control items despite improvements to the overall supply chain (Peery-Wolf et al., 2021). Some local and state governments made efforts to distribute PPE to low-income individuals, but efforts were piecemeal, and there was

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⁷ Social determinants of health include such factors as education, employment, health systems and services, housing, income and wealth, the physical environment, public safety, the social environment, and transportation (NASEM, 2017b).

no overarching federal effort to ensure equity in PPE distribution or access. In a summer 2020 survey of 12 states conducted by the National Governors Association, only 3 states reported specific efforts to procure and distribute PPE and/or cloth face coverings for low-income individuals. These activities were performed through either a one-time purchase order, distribution via the Department of Human Services, or a Health Equity Task Force (NGA, 2020).

While federal disaster aid disbursed to counties through the Federal Emergency Management Agency (FEMA) has recently demonstrated an emphasis on equity, disaster response efforts on all levels run the risk of not reaching vulnerable and stigmatized populations, and there are still improvements to be made in addressing disaster recovery in areas with more socially vulnerable populations (Domingue and Emrich, 2019). In 2017, the Thomas fire in California illustrated how government disaster response can fail to reach all communities equitably. Although the fire affected people of all income levels, local immigrant rights and environmental justice groups had to step in to provide such essential services as access to emergency information in multiple languages (e.g., Spanish and Indigenous languages), labor protections for farmworkers threatened by exposure to smoke, and a relief fund for undocumented immigrants who were ineligible for aid from the federal government (Méndez et al., 2020). Domingue and Emrich (2019) argue that a wide range of social vulnerability⁸ factors should be incorporated into decision-making processes around disaster funding allocations to prevent disparities (Domingue and Emrich, 2019).

Even if information about how to protect oneself from air pollution or infectious disease is disseminated equitably to all groups, preexisting health and social inequalities may be exacerbated if only the affluent can afford to adopt a public health recommendation for respiratory protection (McDonald et al., 2020). Being prepared for a disaster is not possible for those with financial barriers and limited social connections and support (Blake et al., 2017). And for those who can afford respiratory protective devices, the effectiveness of those devices will be undermined if they are chosen or used improperly (Seltenrich, 2017).

Summary and Synthesis

Although there were potential pathways for respirators to reach the population in the United States prior to the COVID-19 pandemic, these pathways proved insufficient to meet the needs of the public. Moreover, the existing supply of respirators was inequitably distributed across the many

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⁸ Vulnerability denotes individuals’ likelihood of being exposed to a hazard because of who they are; where they work, study, play; or where they live.

subgroups of the population. These findings suggest the need to reconsider how best to supply respiratory protective devices for the public and ensure that access is equitable.

CHALLENGES AND LIMITATIONS WITH THE PUBLIC’S USE OF RESPIRATORY PROTECTIVE DEVICES

The previous section examined the gaps and challenges related to ensuring access to respiratory protective devices for the public. This section explores the challenges to the public’s effective and safe use of respiratory protective devices. Considerations for education and communication strategies and other behavioral interventions are discussed in the section that follows.

Uncertainty of Effectiveness of Current Devices Against Varied Inhalation Hazards

As described in greater detail in Appendix B, the effectiveness of respiratory protective devices can vary considerably depending on the size distribution of the aerosol hazard in question (Leith et al., 2021). Various inhalation hazards, such as mold, influenza virus, and wildfire smoke, have different size characteristics; thus, for example, a respiratory protective device that is effective at controlling exposure to mold spores may be less effective for certain elements of wildfire smoke. While an RPP in an occupational setting is designed to respond to changing requirements for devices based on the identification and monitoring of established OSHA occupational exposure limits, public health agencies are challenged in establishing guidelines for the selection and use of respiratory protective devices because for many inhalation hazards facing the public, both exposure levels and safe levels are unknown. Determining the acceptability of risk is difficult. Moreover, variations in the efficacy of various devices in protecting against different inhalation hazards pose a challenge with respect to communicating uncertainties around the expected benefits of use by the public (i.e., the relative reduction in the risk from exposure).

Several additional factors beyond the efficacy of respiratory protective devices contribute to this uncertainty in expected benefits. First, data on dose-response relationships for some agents are inadequately characterized

(e.g., emerging hazards) or have not yet been precisely described (e.g., pandemic influenza and mold). Moreover, such immunogenic hazards as mold can present unique challenges because acute exposures may prime the immune system for more chronic effects (i.e., sensitization) later on. While exposure responses are better known for wildfire smoke and urban air pollution (Cascio, 2018; Holm et al., 2021; Liu et al., 2015a; Reid et al., 2016; Richardson et al., 2012), and there is emerging evidence on the effectiveness of respiratory protective devices in protecting the public from these hazards (Holm et al., 2021; Kodros et al., 2021; Laumbach, 2019; Rajagopalan et al., 2020; Shi et al., 2017), the actual reduction in risk from the use of different devices across different levels of exposure remains unclear. Additionally, evidence of efficacy for respiratory protective devices from randomized controlled trials (RCTs) is generally lacking, as such trials have been underpowered (Bundgaard et al., 2020) and are challenging to implement when studying exogenous risk factors and nonclinical interventions. Finally, multiple and diverse potential exposure settings (e.g., home, school, transit, recreational facilities) complicate exposure assessment.

Population Heterogeneity

Greater heterogeneity in the general population than in worker populations (e.g., age, health status) creates unique challenges for the public’s use of respiratory protective devices. The subsections below address some of the most critical population groups.

Infants and Children

Children are both uniquely vulnerable and uniquely susceptible to environmental hazards, including inhalation hazards (AAP Council, 2019; Holm et al., 2021). They breathe more air per kilogram of body mass relative to adults, and therefore receive a more concentrated dose following toxicant exposure. Additionally, children are more active than adults and spend more time at higher breathing rates in relation to body weight (Holm et al., 2021). Additionally, insults during periods of growth and development may have outsized effects by disrupting development.

As discussed above, because respirators are designed for use in conjunction with an RPP in an occupational setting, manufacturers do not account for the fit requirements of populations typically absent from the workforce, such as children (Goh et al., 2019). Children have a greater variety of face sizes relative to adults, with particularly rapid growth before age 10 (Smith et al., 2020). Indeed, regardless of the type of device (respirator, surgical mask, or fabric face covering), children are less protected from inhalation hazards than are adults. One study showed that both respirators and

surgical masks reduced children’s exposures, although the reduction was less than that in adults (van der Sande et al., 2008).

Children also have physiologic differences from adults that may make respirator use more challenging and necessitate innovations in device design. Compared with adults, lower inspiratory and expiratory pressures generated for breathing may make children (especially at younger ages) more sensitive to the increased breathing resistance (Verma et al., 2019) exerted by filtration material. Additionally, younger children may be unable to describe difficulties with respirator use because their conceptual understanding of causation is not fully developed (Koslowski and Masnick, 2010).

The Elderly

Relative to younger adults, elderly individuals tend to be more vulnerable to respiratory infections, such as influenza and COVID-19, as well as to air pollution from fossil fuel combustion and wildfire smoke (Cascio, 2018; Di et al., 2017; Wu et al., 2020). Thus they are a priority for respiratory protection and proper training in its use. However, the fit of respirators tends to be worse, on average, among older versus younger adults (Lee et al., 2004).

People with Chronic Health Conditions

People with chronic health conditions are more susceptible to airborne pollutants and viral infections relative to those without such conditions and so may appropriately be targeted for respiratory protection. For example, individuals with asthma (children and adults) are more susceptible than the general population to wildfire smoke (EPA et al., 2019; Holm et al., 2021). People who are immunocompromised (e.g., transplant recipients, cancer patients, and those with immune diseases treated with immunosuppressive medications) are especially susceptible to respiratory infections. These groups are likely to benefit greatly from respiratory protection, yet some chronic health conditions (e.g., advanced heart failure, lung disease) may also increase risks of adverse consequences from prolonged use of respiratory protective devices.

People with Physical or Mental Disabilities

Respirators are not designed with attention to the needs of users with physical or mental disabilities. For example, instructions and educational materials on the use of these devices are geared only to the end user, whereas for those with disabilities, such materials may need to be oriented

to caregivers or partners to guide them in assisting with correct placement on the user (Kobayashi et al., 2020). Additional research would likely be needed to ensure that current or future FFRs could be used safely and effectively by these populations. More research is needed in general to understand what population accommodations are required and the extent to which those requirements can be met by currently available devices or necessitate the development of new products.

Ensuring Fit in the Absence of Fit Testing for the Public

The fit of a respirator to an individual’s face is determined by many factors, including the respirator design and size and the user’s facial dimensions. Assessing whether a user will receive the expected level of protection from a respirator therefore necessitates fit testing, a required component of workplace RPPs.

Although there is currently no universal or standard sizing for respirators, most are sold in three sizes (small, medium, and large), with some manufacturers making extra small and extra large models. Manufacturers design respirators to fit facial dimensions from a fit panel,⁹ which is composed of a group of people intended to be physically representative of the facial characteristics of likely occupational users. However, fit panels are based on a standard set of dimensions that do not necessarily reflect the heterogeneity in facial features among members of the public. For example, such features as facial length and width are known to vary with age, sex, race, and ethnicity (McMahon et al., 2008; Wilkinson et al., 2010; Zhuang et al., 2016). The fit of respirators, particularly FFRs, has been shown to be disproportionately poor for female users and users of a variety of ethnic and racial backgrounds (Regli et al., 2021); workplace studies have demonstrated that women tend to pass respirator fit tests less frequently relative to men (Lee et al., 2004; McMahon et al., 2008), and Asians less frequently than other races (Wilkinson et al., 2010). Most of these variations have been explored in samples of working adults, and these findings may be generalizable to similar demographic groups among the public. Studies in children are more limited, however. Poor fit of devices on the faces of children and the resulting leakage around the edges of the device likely contribute to reduced protection. Smaller respirator models have been used for immunosuppressed children when they are in environments

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⁹ Fit panels are used by researchers, manufacturers, and regulators to guide research, product development, and the testing and certification of devices (Chen et al., 2009). An example of a fit panel currently in use is the NIOSH Bivariate Panel, which is two-dimensional, including face width and length. It was incorporated into the ASTM F3407 Standard Test Method for Respirator Fit Capability for Negative-Pressure Half-Facepiece Particulate Respirators (ASTM, 2021b).

where they would benefit from respiratory protection (St. Jude Children’s Research Hospital, 2021), but there are no respirators marketed specifically for children in the United States.

Beyond challenges related to variation in facial features, other physical characteristics of users can impede fit. Facial hair is a barrier to obtaining and maintaining a facial seal on tight-fitting half- or full-face negative pressure respirators (ANSI, 2015). Facial hair remains one of the most contentious topics in managing an industrial respirator program and is an even more challenging issue for the public in the absence of an RPP. Additionally, many tight-fitting respirator designs fail to accommodate certain hairstyles, and large quantities of hair can interfere with firmly seating the respirator straps on the head and affect the respirator seal, as well as the ability to wear the respirator at all (3M, 2020).

The ability of a user to don the device correctly is also critical for ensuring fit. Research quantifying the fit achieved by members of the public when respirators are used without fit testing is limited. In one study of naïve users, only 24 percent were able to don an N95 FFR correctly when asked by a researcher to do so (Cummings et al., 2007). Common errors included leaving the nose clip untightened, putting the straps in the wrong place, and wearing the device upside down (Cummings et al., 2007). Another study found that while the majority of untrained participants were able to don an N95 FFR properly and achieve a fit factor of 2, fewer than 25 percent were able to achieve a fit factor of 100, which is expected for use of the device in workplace settings (Brosseau, 2010).

These issues illustrate how, in the context of public use, there is no established system for ensuring that respiratory protective devices can provide all (or most) people with a sufficient level of protection. Because respirators are not designed to fit all user facial structures universally, devices with poor fitting characteristics prove to be a challenge for achieving the intended level of protection even when fit tested (Campbell et al., 2001). Innovation in product design—specifically in terms of improving the fitting characteristics of devices (see Chapter 2, Box 2-6)—therefore is essential to meet the requirements of all users and provide them access to devices that are both acceptable and effective for their intended purpose. In addition to such innovation, it is important to provide information to the public regarding the fitting characteristics of devices on the market. Thus, the need to ensure proper fit of respiratory protective devices for the public represents both a technology and a communication challenge.

Qualitative or quantitative fit testing is both time- and resource-intensive. Thus, scaling up the current occupational paradigm for this process to a nationwide level may be impractical, especially when time is of the essence, as is the case during public health emergencies and disaster events. Moreover, the number of professionals (i.e., industrial hygienists, trained technicians)

needed to perform fit testing on a population level is insufficient. The development of both qualitative and quantitative fit tests that are scalable to members of the public or of devices for which such tests are not required is therefore an important need, as is understanding of the level of protection a device is capable of providing in the absence of fit testing.

Health Risks from Use of Respiratory Protective Devices and Medical Clearance for the Public

Limited research on the health risks associated with respiratory protective devices has been focused specifically on use by the public, whose health profile differs from that of workers. Much of the research that has been conducted in this area, some of which is described below, is related specifically to the use of respirators. Moreover, the majority of studies have involved healthy adults, and have not included such high-risk groups as children, the elderly, or those with chronic heart or lung disease.

Devices that cover the nose and mouth will create a small volume of “dead space” (a portion of each breath that occupies space within the device and does not participate in gas exchange). It is unclear whether the small increase in dead space volume and breathing resistance for certified respiratory protective devices is ever of significant physiological consequence and under what context of use (Bansal et al., 2009; Harber et al., 2009; Johnson, 2016; Jones, 1991; Morishita et al., 2019; Roberge et al., 2010, 2013; Shein et al., 2021). Of note, data on whether use of N95 FFRs can affect physiologic parameters in healthy pregnant women are mixed (Roeckner et al., 2020), although there is agreement that there is no effect on fetal heart rate (Roberge et al., 2014).

Respiratory impairments that might lead to poor tolerance of airflow resistance or the slight increase in dead space include obstructive lung diseases (e.g., chronic obstructive pulmonary disease [COPD] or emphysema, severe asthma, cystic fibrosis), respiratory muscle weakness, chest wall deformities (e.g., kyphoscoliosis), and restrictive interstitial lung diseases (e.g., pulmonary fibrosis, sarcoidosis, occupational lung diseases). Cardiovascular disease that might affect a person’s ability to tolerate prolonged periods of increased work of breathing or slight increases in carbon dioxide levels due to decreased alveolar ventilation include congestive heart failure, ischemic heart disease, and some arrhythmias. Very few studies have evaluated physiologic effects of respirator use in these high-risk groups. With regard to cardiovascular impairments, there is some evidence of decreased cardiac output during use of positive pressure respirators (Arborelius et al., 1983; Bjurstedt et al., 1979), although the impact of common N95 FFRs has not been evaluated in the setting of cardiac disease. N95 FFRs may not be well adapted to COPD patients, and caution may be warranted in this

population, in whom use of these devices may increase the risk of dyspnea and breathing discomfort (Kyung et al., 2020). Overall, the potential risks for members of the public with serious chronic health conditions—a group that likely would benefit the most from respiratory protection against inhalation hazards—remain unknown. Research is needed to

• determine what level of airflow resistance can be tolerated safely for prolonged use without adverse physiologic consequences among those with respiratory or cardiovascular impairment;
• evaluate the potential health benefits of using respirators to reduce noxious or infectious exposures in these high-risk groups compared with the potential health risks of prolonged respirator use; and
• assess how underlying health conditions may impact physiologic responses to use of respiratory protective devices in particular to identify and define safety thresholds for prolonged respiratory use in patients with heart and lung disease based, for example, on minimum inspiratory pressure (measure of inspiratory muscle strength), evidence of chronic hypoventilation, or reduced cardiac function.

Complicating understanding of the safety of respirators, unjustified fears have propagated in the public around a variety of respirator-related health concerns during the COVID-19 pandemic.

Despite the research gaps described above, the limited data generated to date suggest that respirator use is generally well tolerated. Abnormal pulmonary function may not be a serious concern with regard to complications of respirator use by the public. An increase in breathing resistance has been shown to have only a minimal impact on alveolar ventilation (Love et al., 1977; Raven et al., 1981, 1982). The few studies in children also suggest that their use of respirators is generally well tolerated, with minimal change in objectively measured outcomes (Goh et al., 2019; Holm et al., 2021; Lubrano et al., 2021).

To address concerns regarding potential health risks, medical clearance for respirator use is required for participation in a workplace RPP; however, a requirement for medical clearance to use a respiratory protective device is unlikely to be feasible for the public for several reasons. As described later in this chapter, the vast majority of medical providers (even pulmonologists) in the United States have not been trained in the principles of respiratory protection. Yet, physicians and other licensed health care professionals are expected to manage initial medical screening and examination for respirator use, clear people for use of the device, and provide related medical advice (Harber et al., 1996). Ultimately, the question remains as to the locus of responsibility for ensuring that a member of the public can use a respirator safely.

Additionally, guidelines for medical clearance for respirator use in the workplace are outdated and have not yet been developed for use of these devices in other contexts. In occupational settings, there are generally no firm cardiovascular or pulmonary contraindications to respirator use. Despite a long list of “temporarily disqualifying conditions” for occupational clearance for respirator use, the American National Standards Institute (ANSI) concludes that most workers can be cleared if they can perform well on an exercise stress test (ANSI and AIHA, 2006). The health risks of use of respirators are likely to be negligible if a worker is already healthy enough to do the work that requires a respirator. However, many members of the public (e.g., the elderly, adults with chronic health conditions) would not pass this test of fitness, nor could it feasibly be extended to the general population.

The cost of implementing a nationwide program for “doctor’s approval” for use of respiratory protective devices would likely be enormous under the current system. Once the health risks of respirator use, if any, had been defined, a modified model of the occupational approach (questionnaire or survey) could be developed and made available for the public to complete.

Summary and Synthesis

The methods formalized in the occupational respiratory protection model—typically an OSHA-mandated RPP—are not easily scalable to suit the needs and context of public use of respiratory protection. Relative to inhalation hazards in the workplace setting covered by an RPP, inhalation hazards experienced by the public are not entirely known or quantifiable prior to exposure, and fit testing as currently performed is not feasible for all members of the public because of the considerable logistical challenges and prohibitive costs involved in bringing these practices to scale. Additionally, medical clearance guidelines are outdated and lack applicability to the public, which includes users of all ages and health backgrounds not easily comparable to the traditional occupational user, who is likely to be in good enough health to use a respirator. Additional research is needed to understand what contraindications to respirator use might exist for public users and the costs and benefits of respirators for groups at risk of adverse effects from both use of respiratory protection and inhalation hazards. Given the challenges of applying such an occupational model in the context of public use, a new and distinctly different framework is needed to support decision making and practice around the public’s use of respiratory protection in the absence of a formal RPP.

BEHAVIORAL AND EDUCATIONAL CONSIDERATIONS FOR ENSURING EFFECTIVE USE OF RESPIRATORY PROTECTIVE DEVICES BY THE PUBLIC

Because respiratory protective devices, if used incorrectly, may not be effective, and in rare cases may even be harmful to the user, educating the public in their proper use is crucial. (See Box 4-3, which describes lessons learned from a respiratory protection distribution program in Israel regarding the importance of adequate education.) Box 4-4 lists essential questions that need to be addressed in communications aimed at meeting this need.

When respirators are used in occupational settings, OSHA requires training of employees in their proper use, including putting them on and taking them off, the limitations of their use, and how they should be cared for, in addition to requirements for fit testing and evaluation of the effectiveness of the RPP (OSHA, 2011). However, similar requirements for education are not in place for members of the public, contributing to their confusion about which respiratory protective devices they should use to protect against which hazards (Benjamin, 2021; Santana et al., 2020) (see Box 4-1). While guidance and other resources from federal, state, and local entities provide the public with information about the selection and use of various devices (as described later in this chapter), messages from these sources of guidance have not been systematically collected and evaluated (Conway, 2021). As a result, limited evidence is available on the effectiveness of existing educational materials and other interventions designed to promote effective use of respiratory protective devices by the public or by specific subpopulations in the context of specific hazards (see Box 4-4, question 9).

The sections below review evidence from RCTs focused on the effectiveness of providing respiratory protective devices to members of the public to promote protection against specific hazards, the role of “mask mandates” in promoting public use of such devices, and audience needs critical to improving compliance to achieve more effective use.

Evaluations of Interventions to Improve Use of Respiratory Protective Devices by the Public

A recent review reports on the few RCTs that have been conducted in community settings to examine the benefits of providing people with medical/surgical masks or N95 FFRs and educational materials in the form of

written instructions to protect against the spread of coronaviruses and other respiratory viruses (MacIntyre and Chughtai, 2020). However, studies have typically not described these written instructions in detail, and while some evidence is promising, any potential contribution of such educational materials to proper use of the devices and protection against specific hazards remains unclear because of study limitations and confounding factors (see Box 4-4, question 1).

The most promising findings come from an RCT involving Australian adults who received surgical masks with information about infection control, respirators (with information about infection control but no fit testing), or no devices while living with a child with respiratory illness (MacIntyre et al., 2009). While these three groups showed no statistically significant differences in the incidence of influenza-like infections, those who adhered to the daily use of surgical masks and nonfitted respirators (adherence among intervention groups was poor) had a significantly reduced risk of influenza-like illness (MacIntyre et al., 2009).

Another intervention involved providing education, surgical masks, and hand sanitizer gel to crowded mostly Latinx households, together with instructions stating that the surgical masks should be worn by caretakers and sick persons (Larson et al., 2010). Individuals in the intervention group receiving surgical masks and hand sanitizer had reduced incidence of secondary influenza-like illness compared with the control group, who recieved only targeted education (Larson et al., 2010). However, compliance with mask use was poor, and the observed effects may have been driven by improved hand hygiene instead of mask use (Larson et al., 2010). Similar findings resulted from an RCT among students living in an American university’s residence halls during the H1N1 influenza pandemic (Aiello et al., 2010). The trial evaluated three study groups: participants who received a medical mask¹⁰ with written instructions for hand sanitizer and medical mask use, those who received only a medical mask with written instructions on use, and a control group. Influenza-like illness was less likely among students who received a medical mask and information about hand sanitizer and medical mask use compared with those receiving no intervention, but only in the later weeks of the intervention. The researchers found no beneficial effect of receiving a medical mask alone compared with the no-intervention group (Aiello et al., 2010). However, it is unclear what role existing handwashing habits, which were the same between the medical mask only and control groups, had on reduction of illness, and further research is needed to understand the effectiveness of different combinations of interventions (Aiello et al., 2010).

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¹⁰ Medical masks are also commonly refered to as surgical masks. The descriptions of studies in this section use the same term as that used in the published article.

Other RCTs have yielded no significant findings, perhaps as a result of small sample sizes and/or limited compliance. One of these trials was conducted during the COVID-19 pandemic with a large sample of 4,862 adults in Denmark in April–May 2020. The use of respiratory protective devices had not yet been recommended in that country (Bundgaard et al., 2021). Providing (versus not providing) participants with surgical masks and written instructions for use did not result in a statistically significant reduction in SARS-CoV-2 infection rates 1 month later, but adherence to surgical mask use in the intervention group was variable (Bundgaard et al., 2021).

The RCT findings described in this section indicate primarily the need for larger studies to balance the potential impact of confounders, which limit the conclusions that can be drawn from existing evaluations of interventions involving respiratory protective devices. The lack of compliance with instructions among study participants also demonstrates the importance of understanding the sociobehavioral factors that influence the proper use of such devices.

Improving Effective Use of Respiratory Protective Devices During Public Health Emergencies

During the COVID-19 pandemic, public compliance with recommendations related to use of respiratory protective devices increased over time, possibly as a result of public health messaging and mask mandates. For example, a national longitudinal U.S. survey found that self-reported use of face coverings or masks¹¹ increased from more than 39 percent in April 2020 to nearly 89 percent in November 2020, a finding that may reflect improved public health messaging over the course of the pandemic (Crane et al., 2021). A limitation of such survey data, however, is that use of these devices is self-reported and may not reflect actual, consistent, or accurate use.

Epidemiological studies have found that state-issued mask mandates in the United States have been associated with a decrease in COVID-19 case and death growth rates (Guy et al., 2021; Lyu and Wehby, 2020). Such data are supported by evidence of increased uptake of device use behaviors following the issuance of mandates. Observations of shoppers in Wisconsin, for example, indicated an increase in correct use of masks and face coverings from 41 percent in June 2020 to more than 90 percent in August 2020, when a state mandate was put in place (Haischer et al., 2020). Similarly, a survey in Germany showed that a mandatory policy improved compliance with mask use, despite moderate acceptance of mask wearing as an effective intervention, while also reducing perceptions of mask wearers as being sick or vulnerable and increasing perceptions of fairness among individuals

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¹¹ Terminology used in the publication.

in at-risk groups (Betsch et al., 2020). While these data suggest that public health messaging and mask mandates may promote use of respiratory protective devices, it remains unclear which messages have been most effective or for which audiences (see Box 4-4, question 1).

As emphasized previously, the effectiveness of these devices is dependent not just on use but on correct use. Yet research suggests that improper use of such devices among the public is common, even when there is public support for their use. A Japanese survey showed that 83.5 percent of participants knew how to ensure that a medical or nonmedical mask covered the mouth and nose completely (Machida et al., 2020), but only 23.1 percent of respondents self-reported following all of the World Health Organization (WHO) recommendations for correct use. An observational study examining public compliance with a mask mandate in Honolulu and Waikiki conducted in July 2020 found that 77 percent of those observed wore the devices correctly, with the remainder using them incorrectly or not at all (Tamamoto et al., 2020). In another observational study conducted in Hong Kong during the COVID-19 pandemic, 13 percent of pedestrians (of 10,211 observed) were wearing their devices incorrectly—either below the nose (42 percent) or inside out or upside down (35.5 percent) (Tam et al., 2021).

Similar experiences with improper use of respirators by the untrained public were reported following Hurricane Katrina. Cummings and colleagues (2007) randomly selected homes in New Orleans, where public health messaging promoted use of respirators to protect against mold exposure during posthurricane clean up. A survey found that 68 percent of those interviewed were aware of the public health recommendation to use an N95 FFR during mold remediation activities and that at least 30 percent of those participating in remediation activities had used a NIOSH-approved respirator. However, only 24 percent of participants were able to don an N95 FFR correctly (Cummings et al., 2007). Thus, it is important to better understand how to help people avoid common mistakes in device use (see Box 4-4, question 4) and in the case of respirators, whether modified fit tests can be introduced to the public (see Box 4-4, question 12).

Understanding and Addressing Barriers to Effective Use of Respiratory Protective Devices

An important focus for identification of educational needs related to respiratory protection for the public, then, is that such public education be informed by the evidence-based recommendations of medical and public health experts as to which devices are most effective for protection against which hazards, as well as social science evidence regarding gaps and misconceptions in people’s knowledge and other potential barriers to

behavior change (Benjamin, 2021; Bruine de Bruin and Bostrom, 2013; Douglas, 2021; Morgan et al., 2001; NASEM, 2017a). Designing effective public health communication requires understanding why people struggle to implement expert-recommended behaviors. Intervention efforts need to focus on addressing these barriers, in particular those that most undermine effective use of respiratory protective devices for specific threats (see Box 4-4, question 11), and designing communications accordingly.

Barriers to using respiratory protective devices effectively, or using them at all, commonly stem from specific perceptions that need to be addressed in public education efforts (see Box 4-4, question 5). These include both risk perception (Covey et al., 2019; Ferng et al., 2011; He et al., 2021; Nakayachi et al., 2020; Rieger, 2020) and perceptions regarding the effectiveness of respiratory protection (He et al., 2021). Research has found, for example, that misconceptions spread through social media and other informal communication channels can undermine compliance with recommendations to wear a mask or face covering (Hornik et al., 2021; Roozenbeek et al., 2020). The importance of risk communication to address barriers related to (mis)perception of risk is further underscored by experiences from Taiwan with public use of respiratory protection in the context of highly pathogenic avian influenza, as described in Box 4-5.

Effective risk communication and community engagement efforts also need to address the myriad literacy challenges of the U.S. population to ensure that members of the public understand the risks posed by different inhalation hazards. Otherwise, it is unlikely that respiratory protective devices, even those well suited to the user and the hazard, will be used. In the United States, for example, public health messaging encouraging the use of N95 FFRs to protect against wildfire smoke was largely missed or ignored by the public during the 2007 California wildfires, and researchers found that the technical language used in the health messaging may have posed a barrier to compliance (Sugerman et al., 2012).

Findings of adult literacy studies show that the overall literacy rate in the United States is suboptimal, with approximately 43 million U.S. adults possessing low literacy skills such that they cannot compare and contrast information, paraphrase, or draw low-level inferences (ED, 2019). Also important in the present context is science literacy—the knowledge and understanding of scientific concepts and processes required for personal decision making, participation in civic and cultural affairs, and economic productivity (NRC, 1996). A person with scientific literacy can ask about and find or determine answers to questions raised by curiosity about everyday experiences; can describe, explain, and predict natural phenomena; and can read and understand scientific articles in the press and engage in conversation about the validity of their conclusions (NRC, 1996). Science literacy is generally associated with one’s level of formal schooling

and income (NSB, 2016). However, it also intersects with beliefs, values, and public controversies. For example, Drummond and Fischhoff (2017) found that individuals with more scientific knowledge, compared with the average American, are more likely to express beliefs that are consistent with their religious or political identities on issues that are polarized along those lines (e.g., stem cell research, human evolution), but not on issues that are controversial for other reasons (e.g., genetically modified foods). Environmental health literacy has emerged as a distinct form of health literacy focused on preventing environmentally induced diseases, highlighting the importance of community context to the health of various population groups (Finn and O’Fallon, 2017). Attention to environmental health literacy is especially important for underresourced and vulnerable populations whose communities may be more likely to face inhalation threats due to the environmental conditions in which they live (Simonds et al., 2019).

Other reported barriers to effective use of respiratory protective devices to protect against such inhalation hazards as COVID-19, wildfire smoke, and air pollution include, but are not limited to, incorrectly storing, donning, and wearing the device (Lee et al., 2020b); confusion over the proper frequency of changing devices and methods for reuse and decontamination (Chao, 2020b; Matusiak et al., 2020; Scalvenzi et al., 2021; Yu et al., 2021); and usability issues, such as interference with communication, discomfort, and issues with fit (Chao, 2020b; Cheok et al., 2021; Ferng et al., 2011; Labiris et al., 2021; Shelus et al., 2020).

Barriers to effective respiratory protection for these inhalation hazards are also related to the social dimensions of device use and include user perceptions of social acceptability (Barceló and Sheen, 2020; Ferng et al., 2011; Nakayachi et al., 2020; Santana et al., 2020), feelings of embarrassment (Ferng et al., 2011; Seale et al., 2012), and concerns regarding physical appearance (Al Naam et al., 2021; Allison et al., 2010; Rieger, 2020). Santana and colleagues (2020) found that during the 2018 Camp fire, social norms were a salient driver of use of respiratory protection to protect against wildfire smoke. According to the authors, this finding is consistent with results of previous public health research suggesting that during novel events, when information is limited or uncertain, social norms influence decision making (along with the perceived health threat, emotional response, perceived benefits of using protection, and sense of self-efficacy). Logistical and situational barriers, such as lack of access to devices and conflicting guidance, may also interact with intended behavior, affecting actual use behavior (Santana et al., 2020), a finding that highlights the critical need to align policy, guidance, messaging, public awareness, and production and supply to support a rapid response to novel respiratory threats (see Box 4-6 for lessons learned from South Korea).

Understanding the Needs of Specific Subpopulations and Communities

It has long been recognized that effective education addresses the needs of the specific audience for the specific risk at hand. The studies discussed above suggest that barriers to consistent and correct use of respiratory protective devices may vary with particular audiences (Anderson and Stockman, 2021; Barceló and Sheen, 2020; Casola et al., 2021; Chan et al., 2015; Teasdale et al., 2014), and these barriers specific to subpopulations need to be better understood to inform targeted education and communication efforts (see Box 4-4, questions 5 and 8). Educational materials need to be clear to audiences that speak different languages, but also to address other challenges that may vary with sociodemographic characteristics (Clayman et al., 2010).

During the COVID-19 pandemic, for example, concerns were raised that stigma attached to the use of masks and face coverings was especially strong among African American men (Turner-Musa et al., 2020). However, findings of a nationally representative survey conducted in the United States in April–June 2020 suggest that White people were less likely to wear masks to protect against COVID-19 relative to African American, Latinx, and Asian respondents, with White men being the least likely (Hearne and Niño, 2021). Many anecdotal accounts indicate the added stress that wearing masks and other devices has placed on marginalized communities (Felix, 2020).

Residence in an urban or rural area may impact the likelihood of use of respiratory protective devices; however, findings from available studies (Anderson and Stockman, 2021; Callaghan et al., 2021) do not indicate a clear geographic pattern, and more research on this question is needed.

Political affiliation also may impact motivations to use or not use respiratory protective devices. Results of a nationally representative survey conducted in the United States in April 2020 showed the importance of understanding these motivations. Among the survey respondents, 88 percent of Democrats self-reported use of a device, compared with 73 percent of Republicans and 75 percent of third-party/independent voters; these differences could not be explained by differential risk perceptions (Bruine de Bruin et al., 2020).

Age and gender may also affect the likelihood of choosing to wear respiratory protective devices, although more research is needed to understand the contextual factors at play. Results of several studies indicate that women and younger people are more likely to wear devices intended to reduce exposure to air pollution events (Covey et al., 2019; Xiong et al., 2018). However, perceptions of risk lead to variations in this general observation. For example, Covey and colleagues (2019) found that perception of risk during volcanic ash fall is higher among older than among younger people in Japan, leading to greater use of such devices in that demographic.

Summary and Synthesis

Ultimately, respiratory protective devices are effective only if they are used properly. Public awareness, perceived risk, belief in the efficacy of the devices, and social norms all affect consumers’ decisions about using respiratory protection, and public health messaging can play a significant role in the public’s awareness and decision making about use. Numerous barriers, however, impede communicating to the public to address questions around device selection, use, and care. Engagement with the public—both broadly and in a targeted manner—is essential to educate users on best practices in

selecting and using respiratory protective devices and to address resistance to use. This section has identified 13 open questions concerning the needed education for the public (see Box 4-4). Generally, greater public awareness about respiratory protection is necessary, provided by improved and coordinated communication materials. Depending on the particular barriers to effective use of respiratory protective devices, different educational and intervention approaches may be needed that are tailored equitably to all segments of the public. However, substantial data gaps limit understanding of best practices for conveying such information to the public, and further research is needed to test and evaluate optimal approaches.

For inhalation hazards, a combination of intervention approaches may be needed (Conway, 2021), based on a broad understanding of people’s specific needs and other strategies (beyond use of personal respiratory protective devices) they can use to protect themselves (see Box 4-4, question 7). The United States can learn from the experiences in other countries to address the fractures and gaps in the current system and implement a more cohesive framework that can support the provision of respiratory protection to the public during public health emergencies.

STAKEHOLDER ROLES IN COMMUNITY ENGAGEMENT AROUND THE USE OF RESPIRATORY PROTECTION BY THE PUBLIC

The findings discussed above emphasize the critical role for engaging the broader community, including key stakeholder organizations, in connecting with target populations and scaling educational efforts. Key players in these communication efforts may include health care providers and health systems, public health agencies, and other community-based organizations that have broad population reach and engage with specific population groups.

Role of Health Care Providers

Health care providers are often looked to for advice on when to use respiratory protective devices, but they receive little to no training on communicating the risks and benefits associated with respiratory protection, nor are they trained to evaluate whether such devices are safe to use for a given individual. The American Thoracic Society (ATS) has suggested (without providing practical guidance) that physicians are responsible for counseling patients on respirator use and its limitations outside of formal occupational RPPs (e.g., for hobbies or at a workplace that does not require an RPP) and ensuring proper fit testing and use (Harber et al., 1996). These ATS guidelines also state that while medical evaluations are necessary for the safe use of respiratory protective devices, the process for carrying out these evaluations has not been determined, and clinical judgment should be applied (Harber et al., 1996). As a result, the frequency of medical evaluation, which specific tests are performed, and the criteria used to determine fitness to wear a respirator have been shown to vary markedly among practitioners (Desautels et al., 2016).

Lack of knowledge about the proper use of respiratory protection among health care providers is evidenced by the clear gaps identified in physicians’ knowledge about their own use of respirators (NIOSH, 2016), a lack of knowledge that extends to PPE more broadly. The use of respiratory protective devices is not systematically incorporated into medical training. John and colleagues (2017) found that fewer than half of medical students reported receiving training on donning/doffing gloves and gowns, and nearly all made errors. Qualitative research by Barratt and colleagues (2020) on overall PPE use among medical trainees again demonstrated large gaps in knowledge and practice. A Cochrane review found that computer simulation may lead to fewer errors among health care workers in donning PPE, including respiratory protection, and that face-to-face instruction, compared with written materials or video, may reduce noncompliance with donning guidance (Verbeek et al., 2020). No studies have documented the impact of training in personal use of PPE on providers’ ability to counsel patients effectively about the safety of PPE use, which may be an important area for further study.

Lack of emphasis on knowledge about respiratory protection among health care providers is not limited to medical education, but also extends to practice. Hospitals have requirements related to respiratory protection for physicians and other health care workers that may increase their knowledge and skills related to PPE. However, although most hospitals adhere to the requirement that staff undergo an initial medical evaluation and fit testing before they are allowed to wear a respirator in the workplace, only two-thirds of hospitals give employees written notification of the model and

size of the respirator for which they were fit tested (Peterson et al., 2015). Peterson and colleagues (2015), moreover, found that health care workers showed quite variable rates of specific competencies related to respirator use; for example, while 84 percent correctly positioned their respirator, only 15 percent completed seal check procedures, and only about half properly doffed and disposed of their respirators. Thus while health care providers are often pointed to as experts in public health guidance, they are challenged in this role by receiving little or no training in respiratory protection.

Role of the Public Health Community

Much like health care providers, the public health community is expected to serve as a primary resource for the public on the proper use of respiratory protective devices. Like the medical community, however, the public health community receives limited education in respiratory protection to support them in this role. Although a model training program for respiratory protection preparedness at local health departments has been developed, no data are available on the extent to which this training has been provided to public health professionals (Alfano-Sobsey et al., 2006).

There are 3,234 local, regional, and state-run public health agencies in the United States, and respiratory protection for the general population has not been a major focus for these agencies (Alfano-Sobsey et al., 2006). The public health community does focus on respiratory protection for medically vulnerable groups (e.g., the frail elderly), but primarily with an emphasis on communicable diseases, with less attention to wildfire smoke and other environmental exposures. Data from the Association of State and Territorial Health Officials (ASTHO) indicate that in 2019, state-level public health agencies in 36 states focused on indoor air quality, reflecting an increase of 28 percent over 2016. However, only 9 state public health agencies had a focus on outdoor air quality, reflecting a 31 percent decrease since 2016, and no information about the extent or quality of these programs was available (ASTHO, 2021).

Integration of Organizational Relationships to Improve Community Knowledge

Efforts to increase community knowledge of and participation in respiratory protection need to integrate a range of organizational relationships. A large number of organizational channels (e.g., parent- and family-focused organizations, schools, faith-based organizations, health-focused organizations) could be used to improve outreach and connection to different segments of the population with respect to protection against inhalation hazards. To date, these organizational connections have been sporadic and

local, and thus have had limited impact. For example, Moms Clean Air Force is a national community of parents united against air pollution and climate change (Moms Clean Air Force, 2021). With its network of state-based community organizers and more than 1 million members, this is an example of a group that could be engaged to increase respiratory protection planning among families.

Summary and Synthesis

Health care providers and public health agencies are frequently viewed as sources of advice for the public’s use of respiratory protective devices; however, these stakeholders often lack the expertise and resources to address the public’s information needs. Health care providers, who receive little or no training in providing guidance on respiratory protection to their patients, are asked to rely on their clinical judgment in determining clinical fitness for device use and addressing patients’ questions. Public health agencies, although charged with maintaining the health of their community, lack the training to develop their own evidence-based guidance and accessible messaging on the effective use of respiratory protection, and comprehensive guidance from state or federal agencies is not always available. Community organizations are also well placed to play a role in expanding public awareness and practice of respiratory protection behaviors; however, the integration of these groups into the local public health enterprise has been sporadic.

RESPIRATORY PROTECTION GUIDANCE CURRENTLY AVAILABLE FOR THE PUBLIC

If members of the public are expected to make informed decisions about their respiratory protection and that of others, they require clear, consistent guidance. Yet, both the COVID-19 pandemic and recent exposures to wildfire smoke have illustrated a landscape of confusing guidance.

Examples of Challenges in Public-Oriented Guidance for Respiratory Protection

When transmission of COVID-19 surged in the United States in March 2020, CDC initially discouraged the public from wearing any kind of respiratory protective device because of a lack of clarity as to whether the virus could be transmitted via bioaerosols and out-of-date science on airborne transmission at a time of device scarcity. The rationale at the time was based on preserving respirators (N95 FFRs) for health care workers (Cichowicz et al., 2020). In April 2020, CDC recommended that individuals wear a face covering in public to help prevent transmission of the virus, and it continued to emphasize use of face coverings for source control rather than personal respiratory protection for nearly a year (Cichowicz et al., 2020). In February 2021, CDC changed its guidance to recommend that individuals wear two devices—a cloth face covering over a surgical mask—or improve the fit of a single device to provide better source control as well as respiratory protection for themselves. Despite this shift to urging respiratory protection for the public, the agency continued to recommend that the use of N95 FFRs be prioritized for health care workers (CDC, 2021c). Meanwhile, as SARS-CoV-2 variants began to spread globally, some U.S. public health experts urged universal wearing of N95 FFRs to reduce rates of infection (Allen, 2021). In early 2021, several European countries had already begun requiring individuals to wear more protective devices (N95 FFRs, KN95s, FFP2s, or surgical masks) while in public, arguing that cloth and homemade face coverings might not offer sufficient protection against the more highly transmissible coronavirus variants (Morris and Noack, 2021). It was not until September 2021, however, that respirators were incorporated into CDC guidance to the public (CDC, 2021d).

CDC is not alone in promulgating changing guidance. WHO initially encouraged the use of medical masks (surgical or procedural masks) only by individuals with respiratory symptoms and offered no advice about source control by the public (WHO, 2020a). In April 2020, WHO updated its guidance to emphasize reserving medical masks for the medical community and symptomatic persons, and encouraged the public to use social distancing and good hand hygiene to limit the spread of SARS-CoV-2 (WHO, 2020c). It did not begin to encourage the use of fabric face coverings for source control until June 2020 (WHO, 2020b). Despite the spread of more transmissible variants, in December 2020 WHO continued to urge the public to wear only fabric face coverings for source control and restrict the use of medical masks to medical workers, people with coronavirus symptoms, those coming into contact with symptomatic people, and those over 60 or at high risk (WHO, 2020d).

As the vaccination rollout for the public began in 2021, CDC initially stated that vaccinated persons should continue wearing face coverings when around non-household members. Because evidence on the likelihood of COVID-19 transmission by vaccinated persons was not yet available, CDC followed precautionary principles in issuing its guidance. As more evidence became available, the agency released revised guidance in early March 2021, stating that vaccinated persons could gather with other vaccinated persons indoors without face coverings, and vaccinated persons could gather indoors with nonvaccinated persons without face coverings one household at a time (CDC, 2021e). CDC continued to encourage vaccinated persons to wear face coverings in public, when gathering with unvaccinated people from more than one other household, and when visiting with an unvaccinated person at increased risk of severe illness or death from COVID-19 or living with such a person (CDC, 2021e).

Developing situations by their nature require modifications in guidance as the situation changes, yet part of the issue with the above-described changing guidance is the perceived lack of a rationale for the changes. When messages need to change (e.g., transitioning from preserving masks for health care workers to “mask mandates”),¹² very clear communication about the science behind and reason for the change is essential. Because science is an iterative process, issuing guidance in real time is a challenge; rapidly evolving science necessitates rapidly evolving guidance. In the beginning of the COVID-19 pandemic, the science of airborne infectious disease transmission was outdated, and it evolved over the course of 2020 and 2021. These changes in the science and, by extension, the guidance issued can be difficult for a public that has little experience with the scientific process, and the changes can feel abrupt and arbitrary, leading to distrust and noncompliance.

Disagreements among agencies at various levels of government as to who should wear a respirator during a wildfire also left the public with conflicting and confusing advice. Local health agencies and their local governments have disagreed about whether it is appropriate to distribute respirators (e.g., N95 FFRs) to the public. During the Camp fire in 2018, for example, the City of Sacramento had a program in place for distributing N95 FFRs to the public, while supplies lasted, for protection from wildfire smoke. The respirators were dispersed to the city from the California Office of Emergency Services and the California Department of Public Health, with requests being routed through the County of Sacramento (Sacramento City Express, 2018). Sacramento County then released a statement that the

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¹² A mask mandate is an enforceable requirement for the use of a respiratory protective device in specific settings (e.g., indoors, while on transit vehicles). The requirement is not limited to use of medical masks; use of face coverings and respirators will also meet the requirement.

use of an N95 FFR for the Camp fire smoke was not recommended (Cremen and Estrada, 2018).

Disagreement and uncertainty also mark guidance on the use of respirators by children. The Environmental Protection Agency’s (EPA’s) Wildfire Smoke Guide for Public Health Officials states,

Meanwhile, the Pediatric Environmental Health Specialty Unit (PEHSU) released a factsheet stating, “some types of masks (face-coverings that go over your mouth and nose) can protect you and your children from breathing in wildfire smoke” (PEHSU, 2020, p. 1), but the EPA guidance has not yet been updated.

Gaps in Guidance on the Use of Respiratory Protection by the Public

Guidance on the use of respiratory protection by the public is developed and applied by a range of stakeholders, including federal, and state, local, tribal, and territorial (SLTT) agencies. To understand the current landscape of guidance for the public and where additional guidance is needed, the committee collected and reviewed examples of public-focused guidance on use of respiratory protective devices issued by federal agencies, and performed a targeted review of guidance developed or distributed by SLTT public health agencies and air quality agencies. The evaluation of federal guidance was used specifically to identify gaps in authoritative guidance to aid the committee in considering guidance needs, while the review of SLTT guidance allowed the committee to explore the variability of public-focused guidance developed or distributed by these agencies.

Gaps in Federal Guidance

Multiple federal agencies develop and disseminate guidance for the public on the use of respiratory protection. For example, EPA, which regulates environmental pollutants and provides air monitoring data, has produced guidance for public health officials on protecting the public from wildfire smoke, including the use of respiratory protective devices. As discussed above, CDC has published numerous guidance on the use of respiratory protection by the public during the COVID-19 pandemic. To explore

existing gaps in federal-level public-oriented guidance, the committee focused its examination on examples of authoritative guidance that is broadly targeted to the public or is used by SLTT public health agencies to develop content for guidance targeting local communities (see Box 4-7 for selected examples). These authoritative examples of guidance were considered with reference to the identified knowledge gaps outlined earlier in Box 4-1 to identify gaps in guidance on the use of respiratory protection by the public.

Generally, the committee found that hazards of concern covered by these guidance examples vary by agency, with EPA and FEMA providing guidance on wildfire smoke and air pollution and CDC offering guidance on COVID-19, as well as wildfire smoke, air pollution, and mold in some instances. These examples of guidance are intended to serve different purposes, but are all oriented to the public’s use of respiratory protection. For example, some of the information included is designed for use by SLTT public health agencies in developing consistent and comprehensive guidance on use of respiratory protection, while other examples are factsheets intended for use directly by the public. Across the guidance reviewed, the greatest variability in content relates to the level of detail on how, when, and why respiratory protection should be used for a given hazard and to the means used to enhance the accessibility of

that information for the intended audience (e.g., use of graphics, multiple languages, alternative formats). Material from one source of guidance is often used to develop another source or includes links to other foundational information from the same or other federal agencies.

An assessment of this material guided by the information needs in Box 4-1 highlighted several content gaps in some or all of these examples regardless of the hazard of concern. First, few examples of public-oriented guidance provide sufficient detail on where respiratory protection can be purchased (e.g., local drugstore, direct from manufacturers), and none of the examples provide information about the approximate cost of products. In the context of the use of respiratory protective devices as source control for COVID-19, sufficient guidance is available on what type of product to use, but no clear information is included on how these products can be accessed and how the consumer can confirm that the correct product is being purchased. Guidance on the use of respirators for protection from COVID-19 directs the reader to purchase from a “reputable seller.” Clear information for the potential users of respiratory protection about where they can find the appropriate devices, who reputable sellers are, and how they can know they are buying the right products would reduce confusion and increase the likelihood of an appropriate device being acquired.

Additionally, gaps in guidance exist around conveying all critical aspects of effective use of respiratory protective devices—specifically, how to ensure that the device fits, how to put it on and take it off correctly, when the device should be worn, when it has reached the end of its lifespan, and how it should be cared for. Relatively comprehensive sources of guidance, such as CDC’s Your Guide to Masks and Types of Masks and Respirators, are available with respect to prevention of COVID-19 transmission and are included as links on multiple CDC webpages. Yet, available FEMA guidance lacks sufficient detail to support users in knowing how and when to use respirators to prevent exposure to wildfire smoke or how long a device can be used before it should be discarded. In general, the available guidance on exposure to wildfire smoke lacks clear information on when exactly a respirator should be worn, stating, for example, that respirators should be worn during an “extended period of time in smoky air or an ash-covered area” (EPA, 2021) without defining what length of exposure or what level of air quality calls for wearing a respirator outside or even indoors. Failure to provide such specifics of use causes confusion and creates the potential for incorrect use.

Available guidance for the public also lacks sufficient detail on who can safely use what type of respiratory protective device. In a few cases, certain users, such as very young children, are directed not to use respiratory protection at all. In other cases, the guidance provides only vague information about whether individuals with certain health conditions should use

respiratory protective devices. Wildfire Smoke: A Guide for Public Health Officials notes that some users with heart and lung conditions may need to discuss respirator use with their medical provider to confirm that there are no significant health risks involved (EPA et al., 2019). Overall, the guidance offers only very limited information about the baseline health requirements for users and whether there are any risks to use.

Relatedly, the guidance lacks information on respiratory protection targeted specifically to vulnerable groups, such as children and others (e.g., pregnant women, the elderly), who are at particular risk from exposure to inhalation hazards but may be unable to find respiratory protective devices tailored to their needs. Public-oriented guidance needs to provide clarity around who can wear respiratory protective devices in what contexts, as discussed above, and evidence-based alternative precautions for reducing health risks for these groups.

Furthermore, gaps in guidance, as well as in research, relate to the degree of protection that can be expected from a respiratory protective device in different contexts of use. For occupational contexts, assigned protection factors indicate the level of protection a worker can expect when a respirator is used as part of an RPP. By contrast, no guidance for the public provides quantitative estimates of protection. For example, if a mask is worn during wildfire ash cleanup without formal fit testing, how much protection can be expected? Similarly, how much personal respiratory protection is provided by a device acting as source control? This information represents a critical research need and could be highly beneficial to users in improving their awareness of the protection they are receiving and ensuring that they select the appropriate device.

Emergency preparedness organizations at the federal and state levels could address respiratory protection more broadly and comprehensively. For example, the federal government’s ready.gov website provides a packing list for a basic disaster preparedness kit that includes only a dust mask “to help filter contaminated air” (Ready.gov, 2021). A COVID-19 addendum to the site suggests including a “mask” for all family members, but with no specificity on type or fit. New York’s preparedness website (Prepare. NY.Gov) provides two different lists of supplies for an emergency kit, one of which describes including “face masks,” and the other N95 FFRs. A multilingual brochure on this same website recommends including dust masks (New York State, n.d.). None of these sources provide any information about the different circumstances under which different types of respiratory protective devices are appropriately used. Developing one set of coordinated messages that could be used by multiple groups would reduce confusion and duplication of effort in developing such materials.

Guidance from SLTT Public Health and Air Quality Agencies

A paucity of literature addresses the extent to which public health and air quality agencies are able to reach the public, and particularly vulnerable groups, with accessible messaging. To explore this issue and understand the variability of public-focused guidance on respiratory protection across various agencies, the committee reviewed available guidance from SLTT agencies along four dimensions: (1) FEMA region;¹³ (2) jurisdiction type (e.g., state, local, regional, territorial, tribal); (3) jurisdiction demographic (e.g., urban, suburban, rural); and (4) agency type (e.g., public health versus air quality). The committee devised a sampling strategy along these dimensions to guide the selective sampling of publicly available guidance from the webpages of 13 public health and air quality agencies (Alexandria Department of Public Health, 2021; BPHC, 2021; CDPH, 2019; Deschutes County Health Services, 2020; Franklin County Kansas, 2021; Fulton County Board of Health, 2021; Navajo Nation, 2021; NM DOH, 2020; OHA, 2021; Puerto Rico Department of Health, 2021; Tri-County Health Department, 2021; Utah Department of Environmental Quality, 2020). These agencies were selected to reflect the organizational heterogeneity and regional and demographic diversity that characterize such agencies throughout the United States. The databases of the National Association of County and City Health Officials’ (NACCHO’s) Directory of Local Health Departments and the National Association of Clean Air Agencies were used for this search. The committee found that the majority of the relevant content on these websites was focused on COVID-19, with only three agencies including wildfire smoke and none including mold or other inhalation hazards.

Several overarching themes emerged from this evaluation. First, related to selection of respiratory protective devices, there was wide agreement across the guidance surveyed that in the context of COVID-19, N95 FFRs and other such respirators should not be used by the public and should be reserved for health care workers. The public was instead encouraged to make use of face coverings, and the guidance often included how to select or make homemade face coverings. In the context of wildfire smoke, the reverse was true: the guidance stated that while cloth face coverings could be used to reduce the spread of COVID-19, they would not protect individuals against wildfire smoke or other small particulate matter.

Second, with respect to variability in types of information and level of detail provided, while the information presented across the public health and air quality sites was broadly accurate, it varied in the types of information provided, level of detail, and format:

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¹³ FEMA divides the continental United States and its territories into 10 geographic regions.

• Selection: Almost all of the sites provided detailed guidance on when and where masks should be used, especially with regard to COVID-19.
• Use: About one-third of the sites addressed how to don and doff cloth face coverings safely.
• Accessibility of information: About half of the sites provided information via videos or infographics (or links to them) in addition to plain text. Only four of the sites provided translations of the guidance in multiple languages.
• Homogeneity of guidance: Despite differing levels of detail and formats, the guidance was largely consistent across the different public health and air quality websites reviewed. In the context of COVID-19, the guidance often cited CDC, and links to CDC and other federal resources were often provided.

It should be noted that this survey of public health and air quality guidance was conducted in April 2021, and that in the context of COVID-19 especially, respiratory protection guidance for the public may have been much different or more heterogeneous closer to the start of the pandemic and may have evolved as the supply of respirators increased.

Summary and Synthesis

The public requires clear guidance on when to use respiratory protective devices for protection against specific inhalation hazards, such as wildfire smoke, ambient air pollution, volcanic ash, and infectious agents. However, there is no unified, authoritative system for identifying inhalation hazards—either existing or emerging—that may warrant use of respiratory protection by the public. There also is no consistent system for evaluating the potential exposures and health risks to determine whether use of respiratory protection by the public is indicated under certain conditions. Consequently, authoritative guidance to the public on the use of respiratory protective devices has reflected the challenge of adapting to changes in the science and providing effective messaging to critical user populations. Additionally, the authoritative federal guidance that is available currently lacks sufficient information about the degree of protection provided by various devices in terms of both source control and personal respiratory protection in different use contexts that are relevant to the public. Finally, the public requires more guidance on the procurement of devices, as well as clearer statements on health risks associated with their use, to increase users’ confidence in their selection of a respiratory protective device for the hazard of concern.

CONCLUDING REMARKS

From a systems perspective, there are multiple failure points in the sequence from the selection of a respiratory protective device to achievement of the intended level of protection. There is a need for a stable supply chain with the capacity to respond to surges, and more concerted efforts to ensure equitable access to respiratory protective devices. There is an overarching need for training and education—efforts normally undertaken in the context of an RPP—on how to use respiratory protective devices to mitigate inhalation hazards, including guidance for users on length of use, donning and doffing, risks of fomite transmission, and physiologic limitations of using a device. There is a critical need for consistent messaging to the public to overcome these challenges and limitations. Above all, the committee finds that experience to date in providing respiratory protection to the public indicates the need for a systems approach that acknowledges the critical importance of addressing each failure point in a systematic way.

This need could be met by a unified and authoritative source that is empowered to ensure the availability of respiratory protective devices for diverse populations (including children), provide answers for the research priorities noted throughout this chapter, and address the knowledge gaps regarding respiratory protection for the public laid out in Box 4-1—a source that is dedicated to the health and safety of the public, especially in the event of a public health emergency. The architecture for such a framework for respiratory protection for the public is discussed in Chapter 7.

REFERENCES

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