to evaluate the relative importance of various measures of particulate and gaseous air pollution as predictors of daily mortality in inchon , south korea , the association between total daily mortality and air pollution was investigated for a 20-month period ( january 1995 through august 1996 ) . 
 poisson regression was used to regress daily death counts on each air pollutant , controlling for time trends , season , and meteorologic influences such as temperature and relative humidity . 
 regression coefficients of a 5-day moving average of particulate matter less than or = to 10 microm in aerodynamic diameter ( pm(10 ) ) on total mortality were positively significant when considered separately and simultaneously with other pollutants in the model . 
 pm(10 ) remained significant when the models were confined to cardiovascular or respiratory mortality . 
 sulfur dioxide ( so(2 ) ) and carbon monoxide ( co ) were significantly related to respiratory mortality in the single - pollutant model . 
 ozone exposure was not statistically significant with regard to mortality in the above models , and graphic analysis showed that the relationship was nonlinear 
 . a combined index of pm(10 ) , nitrogen dioxide , so(2 ) , and co seemed to better explain the exposure - response relationship with total mortality than an individual air pollutant . 
 pollutants should be considered together in the risk assessment of air pollution , as opposed to measuring the risk of individual pollutants.imagesfigure 1figure 2figure 3figure 4