Zunyi is a city seriously polluted by acid rain in southwest China. Few studies have been performed in the region to investigate the respiratory health impact of meteorological conditions. In this study, we did an ecological time-series study to examine the association between climatic parameters (mainly of temperature) and daily numbers of hospital outpatient visits for respiratory diseases in Zunyi. Daily pulmonary morbidity and meteorological data from 1 January 2007 to 1 January 2010 in Zunyi were obtained. A generalized additive model (GAM) in a Poisson regression was used to model the relationship between air temperature and pulmonary morbidity.
For respiratory admissions, there was a linear association. For a 1ºC increase in daily average temperature below a threshold (10ºC), the number of hospital outpatient visits for respiratory morbidity increased by 1.05009331-fold, whereas for a 1ºC increase in daily average temperature above a threshold (10ºC), the number of hospital outpatient visits for respiratory morbidity decreased by 0.99032897-fold over the past year.
Our study offers the first statistically significant evidence in an acid rain-plagued region of China that ambient air temperature has an adverse effect on population respiratory health. The effects should be considered in planning health actions to prevent respiratory diseases and minimize the established health risks.