[Long-term effects of air pollution on the occurrence of respiratory symptoms in adults of Beijing].

To investigate the long-term effects of air pollution on prevalence of respiratory symptoms in adults, in Beijing. A cross-sectional study was conducted in an urban area and a suburban area with different levels of air pollution in October 2008, in Beijing. Respiratory symptoms were investigated by a standard questionnaire from the American Thoracic Society (ATS-DLD-78-A) in 9 052 adults who had lived there for at least two years. The concentrations of air pollutants for recent five years were obtained from Reports on the Quality of the Beijing Environment, Environmental Protection Bureau and Statistics Yearbook. The differences of the prevalence and standardized prevalence of respiratory symptoms in adults between the urban and suburban areas were analyzed by χ(2) test. The standardized prevalences of persistent phlegm and asthma in urban adults were significantly higher than those in suburban adults [(3.06% vs. 2.43%, P<0.05) and (0.65% vs. 0.31%, P<0.01), respectively], but lower than that of the breathless (0.75% vs. 1.12%, P<0.05). The study suggested that ambient air pollution had long-term effects on the prevalence of some respiratory symptoms in adults.