Modeling the Residential Infiltration of Outdoor PM_2.5in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air)

Abstract

Background: Epidemiologic studies of fine particulate matter [aerodynamic diameter ≤ 2.5 μm (PM2.5)] typically use outdoor concentrations as exposure surrogates. Failure to account for variation in residential infiltration efficiencies (Finf) will affect epidemiologic study results.Objective: We aimed to develop models to predict Finf for > 6,000 homes in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), a prospective cohort study of PM2.5 exposure, subclinical cardiovascular disease, and clinical outcomes.Methods: We collected 526 two-week, paired indoor–outdoor PM2.5 filter samples from a subset of study homes. PM2.5 elemental composition was measured by X-ray fluorescence, and Finf was estimated as the indoor/outdoor sulfur ratio. We regressed Finf on meteorologic variables and questionnaire-based predictors in season-specific models. Models were evaluated using the R2 and root mean square error (RMSE) from a 10-fold cross-validation.Results: The mean ± SD Finf across all communities and seasons was 0.62 ± 0.21, and community-specific means ranged from 0.47 ± 0.15 in Winston-Salem, North Carolina, to 0.82 ± 0.14 in New York, New York. Finf was generally greater during the warm (> 18°C) season. Central air conditioning (AC) use, frequency of AC use, and window opening frequency were the most important predictors during the warm season; outdoor temperature and forced-air heat were the best cold-season predictors. The models predicted 60% of the variance in 2-week Finf, with an RMSE of 0.13.Conclusions: We developed intuitive models that can predict Finf using easily obtained variables. Using these models, MESA Air will be the first large epidemiologic study to incorporate variation in residential Finf into an exposure assessment.

Association Between Air Pollution and Coronary Artery Calcification Within Six Metropolitan Areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): A Longitudinal Cohort Study

“…9 Responses, meteorology, and an outdoor PM 2·5 tracer (particulate sulphur assessed in concurrent samples inside and outside selected homes) were used to predict the fraction of ambient PM 2·5 infiltrating homes. 10 Indoor PM 2·5 exposures were calculated as the predicted fortnight's outdoor PM 2·5 concentration multiplied by the weather-specific and residence-specific infiltration fraction. An individually-weighted exposure to ambientderived PM 2·5 (PM 2·5iwa ) for each fortnight was calculated by time-weighting the outdoor concentration by time spent outdoors, and indoor exposure by time spent indoors.…”

Evaluating the Sensitivity of the Mass-Based Particle Removal Calculations for HVAC Filters in ISO 16890 to Assumptions for Aerosol Distributions

“…Indoor aerosols are most commonly a mixture of aerosols that transport from outdoors, and are emitted from indoor sources [41][42][43]. This section explores the impact of the outdoor-to-indoor transport of ambient aerosols alone (i.e., in the absence of indoor sources), while the subsequent section explores the impact of indoor distributions resulting from a combination of both indoor and outdoor sources.…”

Air pollution and public health in a megalopolis: a case study of Moscow

“…Mosecomonitoring (a municipal air quality monitoring service of the Moscow Environmental Protection Department) reported that annual average levels of nitrous dioxide in Moscow air have dropped by a factor of 4, while PM 10 , SO 2 and ozone levels have decreased by a factor of 2 since 2002. PM 10 is an important indicator of air pollution and health effects [13,14,15,16,17,18,19,20,21]. However, a downward trend in NO 2 concentrations has lately flattened off because of rapid growth in traffic intensity [12].…”