Priority among air pollution factors for preventing chronic obstructive pulmonary disease in Shanghai.

The problems that city environmental protection planners face are how important the air pollution exposures are in relation to chronic obstructive pulmonary disease (COPD) in local residents and which factor should be controlled most urgently. The purpose of our study is to determine the control priority among ambient sulphur dioxide (SO2) inhalable particulates (IP) and indoor use of coal to prevent COPD in residents of the city. Ambient air pollution is mainly from SO2 and IP(< 10 nm). Indoor air pollution is mainly from the use of coal for heating and/or cooking. Distribution of ambient SO2, and IP concentrations were described using a quartic trend surface simulation. When stratified by two extreme levels of ambient SO2 and IP and types of fuel used indoors, eight local area populations in four communities with different combinations of exposure levels were selected. In each community a local area population mostly using coal and one mostly burning gas was chosen. Chronic obstructive pulmonary diseases (COPD, ICD 490-493) including chronic bronchitis, asthma and emphysema, are a major cause of death in residents of Shanghai. The relationship between the three air pollution factors and their health effects were analyzed at the level of mortality (1978-1987, 232,459 person-years), prevalence of symptoms (12,037 persons) of COPD, lung function and non-specific immunologic function (514 women). The results show that indoor use of coal has stronger associations with health than estimated exposure to ambient SO2 or IP.