Time-series studies on air pollution and daily outpatient visits for allergic rhinitis in Beijing, China.

To investigate the effects of urban air quality change on health, we carried out a time-series analysis of daily general practitioner consultations for allergic rhinitis (AR) in Beijing, China. Non-parametric generalized additive model (GAM) was used to analyze the highly non-linear or non-monotonic exposure-response relationship between three air pollutants (namely PM₁₀, SO₂ and NO₂) and daily outpatient visits for AR, after controlling for long term trends, the 'day of the week' effect and confounding meteorological factors. The objective of this study was to assess the possible effects of air pollutants on outpatient visits caused by AR in Beijing during the period 2009-2010. Our work indicates that strong associations exist between daily concentration of the three air pollutants and the daily number of outpatients for AR.