The association between air pollution and childhood asthma: United States, 2010-2015

The current population-based study examines the association between county-level ambient air pollution and childhood asthma. Data from the nationally representative 2010–2015 National Health Interview Survey were linked to nationwide fine particulate matter (PM2.5) air pollution data at the county-level from the National Environmental Public Health Tracking Network which utilizes air quality monitoring stations and modeled PM2.5 measurements (Downscaler model data) and adjusted by county-level socioeconomic characteristics data from the 2010–2015 American Community Survey. Multilevel modeling techniques were used to assess the association between PM2.5 annual concentrations (quartiles < 8.11, 8.11–9.50, 9.51–10.59, ≥ 10.60 µg/m3) and current childhood asthma along with two asthma outcomes (episode in the past year, emergency room (ER) visit due to asthma). From 2010 to 2015, there were significant declines in PM2.5 concentrations and asthma outcomes. In unadjusted models, children living in areas with higher PM2.5 concentrations were more likely to have current asthma, ≥1 asthma episode in the past year, and ≥1 ER visit due to asthma compared with children living in areas with the lowest quartile (< 8.11 µg/m3). After adjusting for characteristics at the county, geographic, and child and family-level, significant associations remained for asthma episode, and ER visit among children living in areas with PM2.5 annual concentrations between 9.51 and 10.59 µg/m3 (3rd quartile) compared with children living in areas with the lowest quartile. This study adds to the limited literature by incorporating nationally representative county-, child-, and family-level data to provide a multi-level analysis of the associations between air pollution and childhood asthma in the U.S.