Associations of particulate matter and daily mortality in Bangkok, Thailand

The association between airborne particles and daily mortality has been reported in many locations, but mainly in western countries. There is a need to investigate the association in locations where the emission sources, weather, and other environmental conditions differ from those in western countries. In this study, the acute effects of PM10 and visibility on daily mortality in Bangkok, Thailand, from 1992 to 1997, were examined. A Poisson regression model was developed to estimate the excess daily mortality associated with PM10 and visibility, while controlling for long-term trends, season, and variations in weather. It was found that increasing PM10 and decreasing visibility levels were independently associated with increasing daily mortality from all non-external causes, cardiovascular, respiratory, and other diseases. The observed associations were stronger for respiratory diseases than for cardiovascular and other diseases and were stronger for persons aged > or = 65 years than for those in the younger age group. The results of the PM10/mortality and visibility/mortality models were consistent, suggesting that visibility may be considered as a surrogate marker for the assessment of the adverse health effects of fine particulate matter when data from direct gravimetric measurements are not available.