Impact of Outdoor Air Pollution on Indoor Air Quality in Low-Income Homes during Wildfire Seasons

Shrestha, Prateek; Humphrey, Jamie L.; Carlton, Elizabeth J.; Adgate, John L.; Barton, Kelsey E.; Root, Elisabeth Dowling; Miller, Shelly L.

doi:10.3390/ijerph16193535

Cited by 104 publications

(67 citation statements)

References 72 publications

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“…However, the building spaces nurture relatively conspicuous diversity and abundance of microorganisms that can be harmful as soon as the immunity fails. Homes and other built environments are supposed to be safe protecting us from all undesirable and harmful outdoor air pollutants [3] but indoor concentrations of some pollutants are often two to five times greater than the outdoor ones [4]. Both types of pollutants with indoor and outdoor origins deteriorate the indoor air quality and they are associated with a plethora of health concerns regarding respiratory, cardiovascular, skin, allergy, and even increased mortality [5].…”

Section: Introductionmentioning

confidence: 99%

Microbial, environmental and anthropogenic factors influencing the indoor microbiome of the built environment

2021

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A built environment is a human‐made environment providing surroundings for human occupancy, activities, and settlement. It is supposed to safeguard humans from all undesirable and harmful pollutants; however, indoor concentrations of some pollutants are much greater than that of the outdoors. Bioaerosols infiltrate from the outdoors in addition to many indoor sources of bioaerosols including the use of various chemicals as well as activities like cooking, smoking, cleaning, or even normal movement. They are also associated with a number of serious health concerns. Various ecological factors associated with the generation, the persistence as well as the dispersal of these microbial components of indoor bioaerosols, are discussed in this review, that have not been considered all together till now. The factors like microbial taxa, environmental factors, and anthropogenic activities (human occupancy, activities, and impact of urbanization) are addressed in the review. Effects of both indoor environmental factors like architectural design, lighting, ventilation, temperature, humidity, indoor/outdoor ratio, particulate matter, indoor chemistry as well as outdoor environmental factors like geography, seasons, and meteorology on the microbial concentrations have been discussed. Efforts are underway to design selective pressures for microbes to create a healthy symbiotic built microbiome as the “right” indoor microbiome is a “healthy” indoor microbiome.

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Section: Introductionmentioning

confidence: 99%

Microbial, environmental and anthropogenic factors influencing the indoor microbiome of the built environment

2021

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“…Exposure to elevated levels of wildfire smoke specifically has been linked to many adverse health outcomes [7][8][9][10][11]. During wildfire smoke episodes, air pollutant concentrations can increase substantially, and low-income homes, which typically have high rates of uncontrolled air leakage, are particularly vulnerable [12]. Filtration can be cost-effectively applied to reduce exposures and health impacts of wildfire smoke in buildings [13,14].…”

Section: Introductionmentioning

confidence: 99%

Wildfire Smoke Adjustment Factors for Low-Cost and Professional PM2.5 Monitors with Optical Sensors

Delp

Singer

2020

Sensors

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Air quality monitors using low-cost optical PM2.5 sensors can track the dispersion of wildfire smoke; but quantitative hazard assessment requires a smoke-specific adjustment factor (AF). This study determined AFs for three professional-grade devices and four monitors with low-cost sensors based on measurements inside a well-ventilated lab impacted by the 2018 Camp Fire in California (USA). Using the Thermo TEOM-FDMS as reference, AFs of professional monitors were 0.85 for Grimm mini wide-range aerosol spectrometer, 0.25 for TSI DustTrak, and 0.53 for Thermo pDR1500; AFs for low-cost monitors were 0.59 for AirVisual Pro, 0.48 for PurpleAir Indoor, 0.46 for Air Quality Egg, and 0.60 for eLichens Indoor Air Quality Pro Station. We also compared public data from 53 PurpleAir PA-II monitors to 12 nearby regulatory monitoring stations impacted by Camp Fire smoke and devices near stations impacted by the Carr and Mendocino Complex Fires in California and the Pole Creek Fire in Utah. Camp Fire AFs varied by day and location, with median (interquartile) of 0.48 (0.44–0.53). Adjusted PA-II 4-h average data were generally within ±20% of PM2.5 reported by the monitoring stations. Adjustment improved the accuracy of Air Quality Index (AQI) hazard level reporting, e.g., from 14% to 84% correct in Sacramento during the Camp Fire.

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“…In addition, the levels of BC, CO, and NO2 were consistently higher in homes closer to roads compared to those further away (i.e., > 200m), reflecting the importance of traffic emissions on air quality. Furthermore, activities such as opening a window increased levels of BC, however decreased CO concentrations, suggesting an internal source of CO emissions (such as a gas pilot light) [44]. These studies highlight the variability of PM2.5 levels in buildings with mechanical and natural ventilation systems.…”

Section: Monitoring Studiesmentioning

confidence: 67%

“…The study found median indoor levels of PM2.5 were 4.6 times higher than outdoors. Homes that used mechanical ventilation systems with low efficiency filters had indoor-outdoor ratios that were 18% higher for PM2.5 than those that did not [44], indicating that the outdoor pollutants are brought indoors through ventilation supply air even when filters were in place. This study also evaluated levels of black carbon (BC), CO, and NO2 and found that indoor levels of BC during wildfires were about twice the levels recorded when no wildfire smoke was present.…”

Section: Monitoring Studiesmentioning

confidence: 99%

“…The results showed that a mechanically ventilated building was more resilient to outdoor pollution with lower indoor-outdoor concentration ratios and lower indoor PM2.5 levels. A study conducted in Denver (CO, USA) during the 2016/2017 wildfires season used laser-based optical particle counters (Dylos-1700) to evaluate levels of particulate matter within 28 low-income homes [44]. The study found median indoor levels of PM2.5 were 4.6 times higher than outdoors.…”

Section: Monitoring Studiesmentioning

confidence: 99%

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Improving the Indoor Air Quality of Residential Buildings during Bushfire Smoke Events

Rajagopalan

Goodman

2021

Climate

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Exposure to bushfire smoke is associated with acute and chronic health effects such as respiratory and cardiovascular disease. Residential buildings are important places of refuge from bushfire smoke, however the air quality within these locations can become heavily polluted by smoke infiltration. Consequently, some residential buildings may offer limited protection from exposure to poor air quality, especially during extended smoke events. This paper evaluates the impact of bushfire smoke on indoor air quality within residential buildings and proposes strategies and guidance to reduce indoor levels of particulates and other pollutants. The paper explores the different monitoring techniques used to measure air pollutant and assesses the influence of the building envelope, filtration technologies, and portable air cleaners used to improve indoor air quality. The evaluation found that bushfire smoke can substantially increase the levels of pollutants within residential buildings. Notably, some studies reported indoor levels of PM2.5 of approximately 500µg/m3 during bushfire smoke events. Many Australian homes are very leaky (i.e., >15 ACH) compared to those in countries such as the USA. Strategies such as improving the building envelope will help reduce smoke infiltration, however even in airtight homes pollutant levels will eventually increase over time. Therefore, the appropriate design, selection, and operation of household ventilation systems that include particle filtration will be critical to reduce indoor exposures during prolonged smoke events. Future studies of bushfire smoke intrusion in residences could also focus on filtration technologies that can remove gaseous pollutants.

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Impact of Outdoor Air Pollution on Indoor Air Quality in Low-Income Homes during Wildfire Seasons

Cited by 104 publications

References 72 publications

Microbial, environmental and anthropogenic factors influencing the indoor microbiome of the built environment

Microbial, environmental and anthropogenic factors influencing the indoor microbiome of the built environment

Wildfire Smoke Adjustment Factors for Low-Cost and Professional PM2.5 Monitors with Optical Sensors

Improving the Indoor Air Quality of Residential Buildings during Bushfire Smoke Events

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