Air pollution and weather as the determinants of acute attacks of asthma: Spatiotemporal approach.

Background Although air pollution and weather changes have been identified as putative risk factors that precipitate acute attacks of bronchial asthma, so far there have been no studies that could conclusively establisha clear association. Objectives This study was carried out to investigate the effect of the concentrations of NO2, SO2, and particulate matter on exacerbation of bronchial asthma. Methods A longitudinal study was conducted during February 2014-January 2015. Sixty-one known cases of asthma were recruited from the outpatient department of a chest hospital. Data regarding weather parameter (temperature, rainfall, and relative humidity) and environmental pollution (SO2and NO2) and respirable suspended particulate matter were procured from the Indian Meteorological Department and Delhi Pollution Control Committee, respectively. Association was examined using the generalized estimation equation (GEE). Results Separate models were developed for weather parameter and pollution parameters. This study could not find a significant association between any of the weather parameters and occurrence of asthmatic attacks. In the GEE model, where average values of SO2, NO2, and PM were used, the PM was found to be significantly associated with asthmatic attacks. Conclusion PM was found to increase the risk of exacerbation of asthma three folds.