BACKGROUND: Ambient air pollutants (PM2.5) are components of persistent haze in Beijing during the autumn and winter seasons. MATERIALS: We collected hourly PM2.5 monitoring data for 35 days from 35 sites in Beijing during 2012. We also identified patients developing respiratory infections during the same time period in the same locale. A BME model was used to simulate environmental exposure concentrations over the course of each day. A medical accessibility analysis was performed to exclude the impact of medical availability on the analysis. A spatial analysis was included in the evaluation of the relationship between exposure duration and concentration of PM2.5 with the development of acute respiratory disease. RESULTS: A low concentration of PM2.5 (greater than 35 µg/m3 and less than 115 µg/m3) for at least 3 days was associated with an increased risk of acute respiratory disease. A high concentration of PM2.5 (greater than 115 µg/m3) was associated with an increased risk of infection even after 1 day of exposure.
BACKGROUND: Ambient air pollutants (PM2.5) are components of persistent haze in Beijing during the autumn and winter seasons. MATERIALS: We collected hourly PM2.5 monitoring data for 35 days from 35 sites in Beijing during 2012. We also identified patients developing respiratory infections during the same time period in the same locale. A BME model was used to simulate environmental exposure concentrations over the course of each day. A medical accessibility analysis was performed to exclude the impact of medical availability on the analysis. A spatial analysis was included in the evaluation of the relationship between exposure duration and concentration of PM2.5 with the development of acute respiratory disease. RESULTS: A low concentration of PM2.5 (greater than 35 µg/m3 and less than 115 µg/m3) for at least 3 days was associated with an increased risk of acute respiratory disease. A high concentration of PM2.5 (greater than 115 µg/m3) was associated with an increased risk of infection even after 1 day of exposure.