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7 Practical Mitigation Solutions for Indoor PM
Pages 179-215

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From page 179...
... . INTRODUCTION Mitigation -- as the term is used in this report -- is not just the removal of fine PM from indoor air or the limiting or elimination of exposure to that PM.
From page 180...
... While programs and codes that specified the installation of high-efficiency air filtering would help to signal the importance of this intervention, there is little evidence in the published literature regarding the effectiveness of such measures for particle reduction or the generation of health benefits, along with the challenges associated with their enforcement beyond their initial application at the time of construction or certification. Although some mitigation literature suggests that the primary health benefit of any mitigation measure comes from reducing indoor exposure to outdoor fine PM (e.g., Fisk, 2013)
From page 181...
... and localized exhausts (e.g., kitchen range hood) that remove fine PM and other indoor air pollutants to outside.
From page 182...
... addressing the range of mitigation measures under consideration.
From page 183...
... Papers that addressed PM mitigation and a health outcome and that were relevant to one or more of the four mitigation measure categories (source control, ventilation, PPE, or filtration/air cleaning)
From page 184...
... Findings are grouped by practical mitigation measure category. The purpose of this examination is to highlight what is known about the effectiveness of various mitigation approaches along with the broad themes and gaps found in the course of the literature review.
From page 185...
... US & Navajo Walker et al. Nation: AK, 461 children ages Filtration and No significant difference with education or HEPA air cleaner intervention on lower (2022)
From page 186...
... Source control Asthma daytime symptoms significantly increased in the control group and Eggleston et al. US: "inner- 100 children ages and filtration decreased in the treatment group.
From page 187...
... ages 2–16 is not clear if the health benefits were due to fine PM reduction or other indoor air Adults -- General respiratory focus pollutants, such as NO2. No statistically significant findings on respiratory or pulmonary function or Yoda et al.
From page 188...
... rhinitis Source control 35 adults with Stillerman et al. and filtration Significant improvements in nocturnal nasal and ocular allergy symptoms and US: homes perennial allergic (2010)
From page 189...
... Lin et al. Taiwan: Filtration and university Blood pressure and heart rate elevated in subjects with no filter.
From page 190...
... Denmark: 42 adults living in Indoor air filtration significantly improved microvascular function (MVF–biomarker Bräuner et al. Filtration and Copenhagen; proximity to of inflammation)
From page 191...
... China: Tianjin; 39 healthy Short-term exposure to traffic acutely affected blood pressure, heart rate, and heart Han et al. walking university PPE rate variability, but N95 mask and powered air-purifying respirator interventions (2021)
From page 192...
... Randomized crossover trial of a sham versus true air filtration intervention and estimated associations with time-weighted PM2.5 indoor and outdoor exposures. China: Higher PM2.5 exposure positively associated with the expression interleukin-1 (IL1)
From page 193...
... The effects of (2021) dormitories students air cleaning indoor air purification on lung function indicators including forced expiratory volume in one second (FEV1)
From page 194...
... China: Beijing; 44 children ages Filtration and decrease in fractional exhaled nitrogen oxide. However, heart rate variability was (2019)
From page 195...
... Examples of source-control measures at the policy and behavior level are siting a school away from busy roadways, providing residents with access to clean air shelters during wildfires, electrifying heating and cooking in homes, electrifying school buses, banning the use of candles in schools, and enacting regulatory bans or incentives to reduce the use of high-emitting materials or devices (details about these sources are in Chapter 3) , along with the banning of smoking in indoor environments (e.g., Repace, 2004)
From page 196...
... generally found evidence to indicate that some measures of interventions have health benefits through reducing occupant exposures to indoor air pollutants. However, the measures that are most likely
From page 197...
... children enrolled in NHANES III. Even though the study found that children whose parents reported using ventilation when operating their stove had higher lung function and lower odds of asthma, wheeze, and bronchitis, it was not clear if the health benefits were due to reductions in fine PM or in other indoor air pollutants, such as NO2.
From page 198...
... A room air cleaner will be less effective for removal of fine PM in a larger room and will also be less effective in a room with more ventilation because of competition with other loss processes for fine PM. There are a variety of sizing practices for room air cleaners, including an effective floor area defined in the Association of Home Appliance Manufacturers standard (AHAM, 2020)
From page 199...
... . Some electrically connected air cleaners also emit ozone, a respiratory hazard and chemical oxidant which can lead to a variety of compounds with potentially negative health outcomes, increased concentrations of odorous or irritating compounds, and increased concentrations of fine PM through secondary organic aerosol (SOA)
From page 200...
... , and aesthetics, among other factors. Many of these issues translate to phenomena and behaviors that diminish the effectiveness of air cleaners over time, and this points to a potential bias that results from short study periods in many of the investigations in the literature review because air cleaners likely have a high initial effectiveness and also points to the importance of the messaging for study participants concerning the benefits of air cleaning and effective air cleaner use.
From page 201...
... Respirator use resulted in lower blood pressure and improved heart rate variability parameters (high-frequency power, RSSD, pNN50)
From page 202...
... Participants were randomised in an open crossover trial to a highly efficient mask versus no mask. The use of the mask was associated with a reduction in symptoms, reduction in blood pressure, and improvement in heart rate variability.
From page 203...
... CONCLUSIONS AND RECOMMENDATIONS The information reviewed by the committee in the course of their work leads them to conclude that effective and practical mitigation of exposure to fine particulate matter in homes and schools is currently possible. Such mitigation is possible with a proper combination of source reduction, ventilation, central or in-room filtration, and PPE.
From page 204...
... The trials need to consider exposure scenarios related to indoor versus outdoor sources and acute versus chronic effects as well as a range of interventions, including filtration, ventilation, source control, and personal protective equipment. Researchers should characterize building factors in studies of PM mitigation to appropriately contextualize findings and add to the existing knowledge on strategies to mitigate adverse effects.
From page 205...
... 2021. Real-time measurements of PM2.5 and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes.
From page 206...
... 2011. A randomized trial of air cleaners and a health coach to improve indoor air quality for inner-city children with asthma and secondhand smoke exposure.
From page 207...
... 2019. Different cardiorespiratory effects of indoor air pollution intervention with ionization air purifier: Findings from a randomized, double-blind crossover study among school children in Beijing.
From page 208...
... 2022. Randomized clinical trial of air cleaners to improve indoor air quality and chronic obstructive pulmonary disease health: Results of the CLEAN AIR study.
From page 209...
... 2013. An indoor air filtration study in homes of elderly: Cardiovascular and respiratory effects of exposure to particulate matter.
From page 210...
... 2018. Cardiovascular benefits of short-term indoor air filtration intervention in elderly living in Beijing: An extended analysis of BIAPSY study.
From page 211...
... 2021. The effect of particulate matter reduction by indoor air filter use on respiratory symptoms and lung function: A systematic review and meta-analysis.
From page 212...
... 2017. Cardiorespiratory responses of air filtration: A randomized crossover intervention trial in seniors living in Beijing: Beijing Indoor Air Purifier StudY, BIAPSY.
From page 213...
... 2016. Primary and secondary consequences of indoor air cleaners.
From page 214...
... 2022. Sensitive inflammatory biomarkers of acute fine particulate matter exposure among healthy young adults: Findings from a randomized, double-blind crossover trial on air filtration.
From page 215...
... 2021. Indoor air quality in new and renovated low-income apartments with mechanical ventilation and natural gas cooking in California.


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