Air pollution and daily mortality in three US counties

I used generalized additive models to analyze the time-series of daily tota l nonaccidental and cause-specific (cardiovascular, cerebrovascular, and ch ronic obstructive pulmonary disease) deaths over the period 1987-1995 in th ree major U.S. metropolitan areas: Cook County, Los Angeles County, and Mar icopa County. In all three counties I had monitoring information on particu late matter less than or equal to 10 mu m (PM10), carbon monoxide, sulfur d ioxide, nitrogen dioxide, and ozone. In Los Angeles, monitoring information on particulate matter less than or equal to 2.5 mu m (PM2.5) was available as well. I present the results of both single and multi-pollutant analyses . Air pollution was associated with each of the mortality end points. With respect to the individual components of the pollution mix, the results indi cate considerable heterogeneity of air pollution effects in the different g eographic locations. In general, the gases, particularly CO, but not ozone, were much more strongly associated with mortality than was particulate mat ter. This association was particularly striking in Los Angeles County.