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National Institute of Environmental Health Sciences

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Your Environment. Your Health.

Publication Detail

Title: Reductions in particulate matter concentrations resulting from air filtration: A randomized sham-controlled crossover study.

Authors: Bennett, Deborah H; Moran, Rebecca E; Krakowiak, Paula; Tancredi, Daniel J; Kenyon, Nicholas J; Williams, Jeffery; Fisk, William J

Published In Indoor Air, (2022 Feb)

Abstract: One-hundred seventy-two households were recruited from regions with high outdoor air pollution (Fresno and Riverside, CA) to participate in a randomized, sham-controlled, cross-over study to determine the effectiveness of high-efficiency air filtration to reduce indoor particle exposures. In 129 households, stand-alone HEPA air cleaners were placed in a bedroom and in the main living area. In 43 households, high-efficiency MERV 16 filters were installed in central forced-air heating and cooling systems and the participating households were asked to run the system on a clean-air cycle for 15 min per hour. Participating households that completed the study received true air filtration for a year and sham air filtration for a year. Air pollution samples were collected at approximately 6-month intervals, with two measurements in each of the sham and true filtration periods. One week indoor and outdoor time-integrated samples were collected for measurement of PM2.5 , PM10 , and ultrafine particulate matter (UFP) measured as PM0.2 . Reflectance measurements were also made on the PM2.5 filters to estimate black carbon. True filtration significantly improved indoor air quality, with a 48% reduction in the geometric mean indoor PM0.2 and PM2.5 concentrations, and a 31% reduction in PM10 . Geometric mean concentrations of indoor/outdoor reflectance values, indicating fraction of particles of outdoor origin remaining indoors, decreased by 77%. Improvements in particle concentrations were greater with continuously operating stand-alone air cleaners than with intermittent central system filtration. Keeping windows closed and increased utilization of the filtration systems further improved indoor air quality.

PubMed ID: 35225392 Exiting the NIEHS site

MeSH Terms: Air Filters*; Air Pollutants*/analysis; Air Pollution, Indoor*/analysis; Cross-Over Studies; Environmental Monitoring; Humans; Particulate Matter/analysis

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