Hourly, Daily, Seasonal, and Location-Dependent Trends of PM Exposure in Primary School Aged Children

Abstract

BackgroundFine particulate matter (PM2.5) is a significant air pollutant which has been associated with increased risk of several respiratory diseases, cardiovascular disease (CVD), cognitive impairment, and premature death. Unfortunately, many adverse health outcomes associated with PM2.5 are exacerbated in children. Most previous research on the topic, however, has looked at residential, not in-school, exposures. This study aimed to evaluate school children’s exposure to PM pollution for 48 consecutive hours.MethodsIn this cross-sectional study, we recruited 105 participants from eight middle schools and two university departments around Albany county, NYS. Using personal monitors, we measured individual exposure to PM2.5, decibels of sound, temperature, and relative humidity over a 48-hour period. In addition, we measured in-class concentrations of several other PM pollutants and collected questionnaire/activity pattern data from most participants.ResultsIn-class PM2.5 concentrations never rose above the EPA 24-hour outdoor standard of 35 µg/m3. Nearly a third (29.08%) of the in-home measurements in the fall exceeded this EPA standard, which is 12.9 and 6.6 times as many measurements as in the winter (2.26%) and spring (4.38%), respectively. PM concentrations in winter were consistently lower than in fall and spring according to both personal monitoring (winterMdn = 0.9 µg/m3; springMdn = 2.31 µg/m3; fallMdn = 2.84 µg/m3) and in-class monitoring data.ConclusionAlthough in-school PM pollution levels rarely exceeded the EPA outdoor standards, PM2.5 levels routinely exceeded these standards at home. Peak PM2.5 concentrations in each season occurred at home and after 6pm, but far more frequently and severely in the fall. This suggests that cooking is likely responsible for nighttime PM2.5 concentrations. Larger studies are needed to assess seasonal differences in student’s exposure to PM pollution and help determine if the EPA should establish indoor PM limits for homes and schools.