Long-term health effects of air pollution incorporating horizontal and vertical spatial variations of PM2.5 concentrations

摘要

Background Previous long-term studies have estimated the horizontal spatial variation of particulate matter (PM) based on geospatial dispersion model and satellite information. None has incorporated vertical spatial variation in estimations of exposures and health effects for people living in high rising buildings. Aim To assess the effects on mortality attributable to long-term exposure to PM2.5, incorporating heights of residential addresses for a cohort of older people in Hong Kong enrolled in Elderly Health Centres (EHC). Methods The height above mean sea level and coordinates of 66,820 residents (aged 65+) enrolled between 1998-2001 in 18 EHC in Hong Kong were derived from address data. Individual's annual mean exposures to PM2.5 were modelled (R2=0.94) using NASA's satellite surface extinction coefficients (SEC) linked with the coordinates, inverse heights of residents, and ambient temperatures. Cox regression using subject's age as time-scale was used to assess the hazard ratios (HR) associated with annual mean exposures to PM2.5 on mortality after adjustment for gender, smoking, alcohol, exercise, regular medications, social welfare assistance and education. Results Mean annual exposures to PM2.5 among all subjects were 31-40 μg/m3 in 1998-2011. The excess risk (%; 95% CI) of mortality (HR-1) per 10 μg/m3 increase of PM2.5 was 9.2 (6.3,12.1) for all-natural causes [ICD10:A00-R99]; 12.5 (7.1,17.9) for cardiovascular diseases [100-199] and 21.7 (13.4, 30.1) for ischemic heart diseases [120-125]; 8.2 (1.4,15.1) for respiratory diseases [J00-J47] and 10.8 (2.7,19.0) for influenza and pneumonia [J9-J18]. Conclusions Long-term exposures to PM2.5, taking into account the three-dimensional scale, are strongly associated with mortality for all-natural causes and cardio-respiratory diseases among the older Chinese population in Hong Kong. Acknowledgement We thank Wellcome Trust for fnding of this study.