Time Series (1963-1991) of Mortality and Ambient Air Pollution in California: An Assessment with Annual Data

Abstract

This article discusses (a) a database developed from individual mortality counts from 1963 to 1991, containing monthly and annual average mortality rates for several endpoints for several California counties, and monthly and annual air pollution and climatic data, and (b) descriptive statistical analyses conducted with annual average data. The major coastal urban and nonurban counties in California are included. In the north we include Alameda, Contra Costa, Marin, San Francisco, Santa Clara, and San Mateo, and in the south Los Angeles, Orange, Riverside, San Bernardino, and San Diego counties. The air pollutants include total suspended particulate matter (TSP), Pb, O₃ and total oxidants, SO₄, NO₃, and CO, measured at several stations within these counties. The climatic data include temperature and relative humidity. The mortality rates, defined by the International Classification of Diseases (ICD, Revisions 8 and 9) and standardized by sex, race, and age to the 1980 California population, are those resulting from a number of selected “all causes,” all cancers, lung and respiratory cancers, cardiovascular diseases, and chronic obstructive pulmonary diseases, by county of residence. The population at risk is abstracted from the U.S. Bureau of the Census yearly age-, sex-, and race-specific county-level data and from intercensal estimates. The findings based on annual data indicate that, generally, the counties with less air pollution are characterized by higher mortality. These findings are counterintuitive. Therefore these results are currently being investigated on the basis of monthly average data to 1992, by extending the air-pollution database to include PM-10, nitrates, and sulfates, and by stratifying mortality by age groups.