Correlation between ambient temperature and air pollution index in Beijing

Objective To assess the impact of ambient temperature on air pollution index (API).Methods Using distributed lag nonlinear model,the relative risk of the impact of ambient temperature on API was calculated by using the API data of Beijing during 2001-2012.Results API showed a downward trend in Beijing.There is a significantly negative correlation between the ambient temperature and API,with a correlation coefficient of -0.212 (P<0.001);the relative risk is 1.85 (95 confidence interval95%CI:1.63,2.10) for high temperature (90th percentile of temperature) and 0.38 (95%CI:0.32,0.45) for cold temperature (10th percentile of temperature),and there exists a lag effect and cumulative effect.Conclusion The ambient temperature has an effect on air pollution index.