PNNL

Abstract

Background: Individuals with respiratory conditions, such as asthma, are particularly susceptible to adverse health effects associated with higher levels of ambient air pollution and temperature exposures. We used a panel study to evaluate whether hourly levels of fine particulate matter (PM2.5) and dry bulb globe temperature (DBGT) are associated with the lung function of adult participants with asthma. Methods: Global positioning system (GPS) location, respiratory function, and self-reports of asthma medication usage and symptoms were collected as part of the Exposure, Location, and Lung Function (ELF) study. Hourly ambient PM2.5 and DBGT exposures were estimated by integrating air quality and temperature public records with time-activity patterns using GPS coordinates for each participant.. The relationships between acute PM2.5, DBGT, rescue bronchodilator use, and lung function were analyzed by multivariate regression. Results: Increasing levels in PM2.5, but not DBGT, were associated with rescue bronchodilator use. After removing the measurements following rescue bronchodilator usage, PM2.5 concentrations at all exposure time frames were not associated with a decrease in lung function, measured as lower FEV1, while DBGT was found to have a significant positive association with lung function. When DBGT was taken into account, the strongest association between cumulative PM2.5 exposures and the use of rescue bronchodilator was identified at the 0-24 (OR=1.030; 95% CI= 1.012-1.049; p-value=0.001) and 0-48 hours (OR=1.030; 95% CI=1.013-1.057; p-value=0.001) prior to lung function measure. When PM2.5 was taken into account, DBGT exposure at hour 0 (b=3.257; SE=0.879; p-value>0.001) and 0-6 (b=2.885; SE=0.903; p-value=0.001) hours before a reading were associated with FEV1. No significant interactions between DBGT and PM2.5 were observed for rescue bronchodilator use or lung function. Conclusions: Short-term increases in PM2.5 was associated with increased rescue bronchodilator use, while DBGT was associated with higher lung function (i.e. FEV1). Further studies are needed to continue to elucidate the mechanisms of acute exposure to PM2.5 and DBGT on lung function in asthmatics.