The relationship of short-term air pollution and weather to ED visits for asthma in Japan

Abstract Introduction The incidence of asthma exacerbation has been increasing in many countries. Environmental factors may play an important role in this trend. We aimed to investigate the relationship of weather conditions and air pollution to significant exacerbation of asthma. Methods The daily number of emergency department (ED) visits by ambulance for asthma was collected through records of the Tokyo Fire Department from January 1 to December 31, 2005. We also collected daily air pollution levels and meteorological data for Tokyo during the same period. Meteorological data included minimum temperature, maximum barometric pressure, maximum relative humidity, and precipitation. Measured air pollutants included sulfur dioxide, nitrogen monoxide, nitrogen oxides, suspended particulate matter, and carbon monoxide. We performed a time series analysis using multivariable-adjusted autoregressive integrated moving average model. The analysis was conducted separately among adults and among children (