Appendix A

Study Approach and Methods

In response to a request by the National Institute for Occupational Safety and Health (NIOSH), the Environmental Protection Agency, and the Department of State, the National Academies of Sciences, Engineering, and Medicine convened the Committee on Respiratory Protection for the Public and Workers Without Respiratory Protection Programs at Their Workplaces. This committee was charged with making recommendations for a framework of responsibilities and authorities that would provide a unified and authoritative source of information and effective oversight for the development, approval, and use of respiratory protection. The committee’s report presents an overview of considerations and needs for use of respiratory protective devices by the public and certain worker groups, along with conclusions and recommendations to address the need for oversight and guidance related to respiratory protection.

STAKEHOLDER ENGAGEMENT AND INFORMATION GATHERING

The committee deliberated from November 2020 to October 2021 and held eight virtual meetings (two meetings in November 2020, followed by meetings in January, April, June, July, August, and October 2021). The two November 2020 meetings and the meetings in January, July, and October 2021 included portions that were open to the public (see the section on Public Session Agendas below). The remainder of the committee meetings were held in closed session.

To inform its deliberations, the committee used several mechanisms to gather information: (1) a 2-day workshop in January 2021 with open public sessions to hear from federal agencies, public health and air quality agencies, worker-oriented nonprofit organizations and research institutions, labor unions, manufacturers, and others; (2) public meetings with sessions on third-party testing and certification of respiratory protective devices, models for federal agency roles and structures for coordinating cross-agency activities, and processes and systems for evaluating infectious agents transmissible by inhalation routes and determining the need for public use of respiratory protection; (3) a request to NIOSH for information on considerations regarding use of third-party testing laboratories and voluntary consensus standards; (4) a series of comprehensive and targeted reviews of factors that influence the effectiveness of respiratory protective devices for their intended use (see the section on Research Methods and Appendix B); and (5) an assessment of authoritative guidance (e.g., from governmental, national labor union, and other prominent worker organization sources) on the use of respiratory protective devices by the public and selected worker groups to identify gaps.

PUBLIC SESSION AGENDAS

First Committee Meeting
Public Session Agenda

Thursday, November 5, 2020
12:30–3:40 p.m. ET
Zoom

OPEN SESSION

Session Objective: To present and clarify as needed the charge to the committee.

Session Objective: To provide additional context for the study, including an overview of the current regulatory environment for respiratory protective devices, with a focus on variable processes for conformity assessment and diversity of key stakeholders.

Second Committee Meeting
Public Session Agenda

Tuesday, November 24, 2020
12:45–1:45 p.m. ET

OPEN SESSION

Third Committee Meeting
Public Session Agenda

Day 1: Monday, January 25, 2021
10:30 a.m.–4:30 p.m. ET

OPEN SESSION

Moderator: Stephanie Holm, Committee Member

Moderator: Robert Harrison, Committee Member

Day 2: Tuesday, January 26, 2021
11:00 a.m.–12:45 p.m. ET

OPEN SESSION

Sixth Committee Meeting
Public Agenda

Friday, July 9, 2021
11:30 a.m.–2:00 p.m. ET

OPEN SESSION

Session Objective: To gather information on the considerations related to third-party certification in the conformity assessment process for respiratory protection.

Session Objective: To explore considerations and lessons learned related to the establishment of new federal organizations.

Session Objective: To explore federal agency roles and coordination mechanisms in a framework to ensure access to and effective use of respiratory protection.

Eighth Committee Meeting
Public Session Agenda

Wednesday, October 6, 2021
3:00–4:00 p.m. ET

RESEARCH METHODS

To address the charge, the committee, guided by input from the study sponsors, identified nine high-priority use scenarios (see Table 1-1) for respiratory protective devices and, for each scenario, conducted a comprehensive or targeted literature review to assess what is currently known regarding the factors that influence the effectiveness of respiratory protective devices. Six of these use scenarios were selected as the focus of comprehensive reviews of the literature, while three were explored via targeted reviews. The methods of the comprehensive reviews are described below. Although literature searches and data extraction were conducted separately for each of the review topics, findings were combined into a single narrative synthesis that describes cross-cutting and unique findings across the use scenarios (see Appendix B). The committee uses the term comprehensive review to address the “deep dives” requested by the sponsors, and notes that the reviews were not systematic reviews, using, for example, Cochrane or other established methods. With the constraints of time and available resources, formal systematic reviews were not feasible.

Additionally, other targeted searches of peer-reviewed and gray literature were carried out to address information needs and support the committee’s conclusions and recommendations. This review effort included the collection of highly cited, foundational articles related to filtration efficiency, breathing resistance, fit, comfort, and usability of respiratory protective devices to provide contextual information for the discussion of findings from the comprehensive reviews. Targeted research also included nonexhaustive collection of public- and worker-oriented guidance from authoritative sources (e.g., federal agencies, national-level unions, and prominent workers organizations) on the selection and use of respiratory protective devices, as well as research on the scope and effectiveness of respiratory protection programs in the United States. Additionally, an analysis of citation data from the Occupational Safety and Health Administration (OSHA) related to the Respiratory Protection Standard (1910.134) was undertaken to inform challenges related to compliance with the standard (methods and data tables included below).

High-Priority Topics for the Comprehensive Reviews

Use Scenario Topics for Comprehensive Review

The selection of the six high-priority use scenario topics for comprehensive review, listed below, was guided by the priority populations and hazards identified by the study sponsors (see Table 1-1). The committee conducted literature searches for air pollution separately from wildfire

smoke, and communicable biological agents separately from noncommunicable biological agents, resulting in 10 separate literature reviews, which were synthesized with a narrative approach.

Comprehensive review topics included:

• Wildland firefighters
  • Wildfire smoke
  • No review conducted on ambient air pollution due to the specific interest in wildfire smoke for this worker population.
• Outdoor workers
  • Air pollution
  • Wildfire smoke
• Outdoor workers
  • Noncommunicable biological agents
• Indoor workers
  • Noncommunicable biological agents
  • Communicable biological agents
• Public
  • Air pollution
  • Wildfire smoke
  • Noncommunicable biological agents
  • Communicable biological agents

The differentiation of indoor workers and outdoor workers for the purposes of the literature searches was driven by the matrix of priority populations and hazards (see Table 1-1), but the committee acknowledges that these distinctions are not always relevant and that many workers perform job functions (and are exposed to inhalation hazards) both indoors and outdoors. The findings presented in the synthesis describe occupation type and location of work, when possible, rather than referring to the broad categories of indoor versus outdoor workers.

Targeted Review Use Scenario Topics

Certain use scenarios were selected for targeted rather than comprehensive review because search terminology overlapped with some of the use scenario topics covered by comprehensive reviews (e.g., search terminology for outdoor workers included some search terms oriented to emergency responders). Targeted reviews were conducted for the use scenarios involving paid and volunteer emergency responders. Findings from these targeted reviews were integrated into Chapter 3 and into the narrative synthesis (see Appendix B).

Comprehensive Review Protocol

Research Question

What is known about the factors that influence the effectiveness of respiratory protection for TARGET POPULATIONS exposed to HAZARDS OF INTEREST? Target populations and hazards of interest are captured in the bulleted list above.

Research Goal and Factors of Interest

The purpose of the 10 individual literature reviews was not to assess the evidence of the effectiveness of respiratory protective devices as measured by distal health outcomes, but rather to review the state of the evidence on the spectrum of factors within the system of respiratory protection (see Figure 1-4 in Chapter 1) that influence the effectiveness of such devices for their intended use. Factors of interest include filtration efficiency; breathing resistance; fit; antimicrobial properties, cleaning, and disinfection; comfort and usability; knowledge, attitudes, beliefs, and perceptions; sociodemographic characteristics of users; communication, education, and training; accessibility; cultural norms; and oversight and enforcement.

Search Strategy and Article Selection Method

Literature searches for each of the 10 review topics were conducted for articles published in English between 1980 and April 2021 in PubMed, Scopus, and EMBASE using the search terms listed below. The literature searches on factors of interest were broken into three overlapping search categories—device, user, and system factors. These delineations, however, are not reflected in the final narrative synthesis, which is organized by factor type (see Appendix B). Records were extracted to EndNote. Article titles and abstracts were screened for further full-text assessment based on the criteria of interest (population and hazard) described above. Additional articles were identified for inclusion for full-text review through reference mining, targeted searches, and committee input. During full-text review, studies that did not address factors affecting the use of respiratory protective devices by the population for the hazard of interest were excluded. Studies that used surrogates rather than the specific hazard of interest (e.g., viable viral particles) to assess such factors as filtration efficiency and fit were not excluded. Table A-1 shows the numbers of articles captured in the searches and remaining after screening for each review. Following the initial screening based on the criteria of interest, committee members applied judgment in selecting articles for ultimate inclusion in the synthesis

TABLE A-1 Articles Captured and Remaining After Screening for Relevance to the Review Topics

and excluded those that had limited relevance or applicability to the U.S. context, as well as those for which there were concerns regarding major methodological limitations (e.g., failure to use reproducible test methods and controls).

Of note, a large body of research on particle and respiratory protection science exists, which includes studies that are not specific to the hazards and populations identified by the high-priority hazard use scenarios. This body of literature was not captured in the committee’s narrowly targeted searches but was reviewed separately (see the section below on targeted reviews of fit, filtration, and other factors). In some cases, key articles were discussed in the introductory section for a given factor to provide context for the findings from the committee’s literature reviews.

Search Terms

Respiratory protective devices: “Respiratory protection”, respirator, facemask, mask, face cover*, filtering facepiece, FFR, N95, N-95, KN95, respiratory protective device, respiratory protective equipment, RPD, elastomeric respirator, particulate respirator, P2, P3, FFP2, FFP3, DS1 and respirator, DS2 and respirator, “community mask”, “barrier mask”, cloth mask, PAPR, APR, air purifying respirator, “breathing apparatus”, SCBA

Populations of interest:

• Public: Public, general public, resident, citizen, non-occupational, pregnan*, child*, communit*, elderly, immunocompromised
• Wildland firefighters: Wildland/wildfire/bush/forest firefight*, wildland fire fight*, firefight*/fire fight*, hotshot crew, hotshot and wildfire
• Indoor workers: Grocery, worker/employee; supermarket, worker/employee; domestic worker; housekeep*; “domestic labor”; “home healthcare”; “home health care”; home care workers; home, aide; factory worker; warehouse worker; meatpacking; confined feeding operation, poultry worker/processing, food manufacturing; food processing; retail worker; residential care workers; food service; shift worker; transit workers; bus drivers; corrections workers; personal care aides; emergency medical technicians; subway workers; ambulance drivers; flight attendants; sanitation workers; security guards; day care workers; social workers; restaurant workers; teachers; janitors; environmental services; building and grounds maintenance and cleaning; emergency responders
• Outdoor workers: “Day laborers”; laborers, outdoor; workers, outdoor; “outdoor work”; agricultural workers (mesh); migrant worker (mesh); undocumented worker (mesh); “seasonal worker”;

• farmworker, farm worker, farmer; forestry, worker; fishery, worker; fruit sorting and packing; crop production; “construction workers”, outdoor, worksite; construction AND jobsite; outdoor, workplace, tradespersons; “construction trades”; asphalt AND workers; highway AND crew; road workers paving contractors; masons; roofer; police (mesh); traffic enforcement; trash/waste/garbage collectors; landscapers; utility workers; postal AND worker; school personnel (i.e., maintenance staff working outdoors)

Hazards of interest:

• Air pollution: Air pollution, dust, particulate matter, particulate air pollution, PM_2.5, air quality (outdoor)
• Wildfire smoke: wildfire smoke, smoke and wildfire/bushfire/forest fire, bushfire smoke, wildland fire smoke
• Communicable biological agents: Virus; influenza; MERS; SARS (SARS-CoV-1, SARS-CoV-2); H1N1; COVID-19; infectious aerosols; viral aerosols; viral droplets; bioaerosol; respiratory infection; TB, tuberculosis, Mycobacterium tuberculosis
• Noncommunicable biological agents: mold; anthrax; aspergill*; fungal bioaerosol; Stachybotrys chartarum, black mold

Respiratory protection factors:

• Device factors: Performance, penetration, leakage, leak, resistance, protection factor, filter, loading, work rate, fit, “fit factor”, pass rate, fit test panel, “fit capability”, airflow, faceseal, face-seal, seal, strap, fabric, material, efficiency, filtration, stability, exertion, dead space, characteristics, features, anthropometr*, breathability, pressure drop
• User factors: Thermal, temperature, heat, moisture, warmth, sweat*, aesthetics, physiological impacts/effects/responses, psychological impact/effects/response, subjective, cleaning, disinfection/decontamination/laundering, glasses, eyewear, fogging, shortness of breath/out of breath, limitations, barriers, reuse/disposal/replacement, communication, interference, intelligibility, weight, age, seal check, fit check, usability, wearability, comfort, discomfort, ease of use, don*, doff*, facial hair, beard, risk perception, heart/cardiovascular, oxygen deficiency, headache, claustrophobic, anxiety, stress, distress, skin irritation, dermatitis, acne, adherence, compliance, acceptability, steriliz*, perception, expression, storage, movement, instructions, access*, knowledge, attitudes, practices
• System factors: Policy, education, training, communication, messaging, cost, supply, instruction, label*, sizing, guidance, risk perception, knowledge, attitude, behavior, production and manufacturing, access/accessibility, availability, belief, trust, distrust, fit testing,

• capacity, compliance, adherence, safety culture, culture, safety and practices, respiratory protection program (RPP), implementation, enforcement, medical screening/clearance

Data Extraction and Narrative Synthesis

For each review, the following baseline information was extracted from included articles to aid in the synthesis of the material: author, title, year, country, setting, study type, data collection method, population, exposure, exposure detail (e.g., particle size, duration of exposure), device factors detailed, user factors detailed, system factors detailed, and qualitative themes (where applicable). The extracted data were used in the development of the narrative synthesis, which summarizes the evidence and describes patterns and themes across the selected literature. Key findings were identified for each of the syntheses and were incorporated into the relevant report chapters to support the committee’s conclusions and recommendations.

Collection of Standards and Authoritative Guidance

As noted above, the committee carried out a separate assessment of the landscape of standards and authoritative guidance on respiratory protection for selected use scenarios to determine where gaps may exist. Guidance included written, visual, or auditory information provided directly to the user or to other stakeholders with roles in disseminating guidance (e.g., employers, public health agencies, clinicians) for the purpose of supporting the selection, proper use, care, and disposal of respiratory protection for the hazard of interest. Standards and guidance were collected through a search of the gray literature, including PPE-info, consensus standards organizations, and reports and webpages of federal agencies, labor unions, professional associations, and academic and nonprofit institutions.

Additionally, a small, nonrandom sample of guidance was also collected from webpages of local, state, tribal, and territorial public health agencies and regional air quality agencies. The sampling process used four dimensions (Federal Emergency Management Agency [FEMA] region, jurisdiction type, jurisdiction demographic, and agency type) to guide the selective sampling of publicly available guidance from the webpages of 10 public health and air quality agencies in a manner that reflects the organizational heterogeneity and regional and demographic diversity in which these agencies operate throughout the United States. This guidance was evaluated to describe the variability of public-focused guidance on respiratory protection, including the hazards addressed, messages used, and recommendations provided. A discussion of the guidance landscape, gaps, and variability can be found in Chapters 3 and 4.

Targeted Review of Fit, Filtration, and Other Factors

A targeted literature review of articles describing fit, filtration, breathing resistance, comfort, and other factors related to usability was conducted to provide context for the committee’s comprehensive reviews. This review focused on highly cited articles that were not restricted in the search by user type or exposure. These searches were conducted in PubMed with no date restrictions. Selected device and user search terms from the comprehensive reviews were used for targeted searches. Within each subject matter search, the top 10 most published authors on the topic were selected and then the relevant titles from the top 50 most cited articles were saved to Endnote for review. Additional articles were included based on committee member input.

Analysis of OSHA Citation Data

As part of its efforts to understand the effectiveness and limitations of workplace respiratory protection programs (see Chapter 3), and specifically, challenges related to compliance with the Respiratory Protection Standard, the committee initiated an analysis of OSHA data on violations issued between January 1, 2015, and December 31, 2020, citing any provision of 1910.134(c)(1) of OSHA’s Respiratory Protection Standard. Data were requested from and provided by OSHA in April 2021, in the form of Excel spreadsheets.¹ Data elements included the name of the cited establishment, site address, date of the citation, North American Industry Classification System (NAICS) code for the cited establishment, inspection type (e.g., whether the inspection was programmed or complaint driven), the violation description, the gravity of the violation, and the penalty amount, among others. Frequency tables (see Tables A-2 through A-4) were generated by a committee consultant from the California Department of Public Health for industry type (NAICS code), gravity, and inspection type data fields for federal OSHA violations.² Mean and median values were generated for the penalty data element (see Table A-5).

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¹ Original data files are available by request through the National Academies’ Public Access Records Office.

² The analysis did not include violations of state OSHA requirements.

TABLE A-2 Frequency of OSHA Respiratory Protection Standard Citations by Industry Type (NAICS Code)

TABLE A-3 Frequency of OSHA Respiratory Protection Standard Citations by Gravity

* There were 687 missing fields for the gravity variable.

TABLE A-4 Frequency of OSHA Respiratory Protection Standard Citations by Inspection Type

TABLE A-5 Summary Statistics on Penalties for OSHA Respiratory Protection Standard Citations

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