To investigate the lag effects and seasonal differences of urban air quality change on human health, we carried out a time-series analysis of daily general practitioner consultations for allergic rhinitis (AR) in Beijing, China. In earlier publications we had assessed the relative risks of air pollutants on AR in Beijing during the period 2009-2010. This article analyzes for the same time period the lag effects of air pollutants and the seasonal effects on daily number of outpatient with allergic rhinitis; differences among age groups and gender groups were also taken into consideration. The results show that, the largest effect RRs of PM(10) were at lag01, lag0, lag01, lag01, and lag01 for the total population, male, female, young/middle aged people (20-60 years age group), and old people (more than 60 years age group), respectively. The largest associations of SO(2) were observed at lag3, lag1, lag3, lag0 and lag0 for the total population, male, female, young people/middle aged people (20-60 years age group), and old people (more than 60 years age group), respectively. The strongest effects of NO(2) were found at lag03 for the total population, female and the young/middle aged people; at lag0 for male and lag03 for elder people. RRs of the three pollutants for AR have shown a decreasing relevance from NO(2) to PM(10) to SO(2). The seasonal effect models show that PM(10), SO(2), and NO(2) had higher risk for AR in the warm season than in the cold season.
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