Relative contributions of different sources of urban aerosols: Application of a new estimation method to multiple sites in Chicago

Abstract

Information on the relative contributions of various types of pollution sources is required by pollution control strategists in planning for cleaner air. A new method for estimating the percentage contributions (source coefficients) of various sources to the total atmospheric aerosol content has recently been published. It requires detailed data on the chemical composition of (1) the urban aerosol and (2) emissions from the various sources considered. Enough data are now available for Chicago to permit a tentative estimation of source coefficients for the following aerosol sources: automobiles, fuel oil burning, cement manufacturing, iron and steel manufacturing, coal burning, and wind-raised soil dust. Comparison of estimated source coefficients for Chicago and published results for the Los Angeles area indicates that the method gives reasonable results. This paper also examines the possibility of applying the method to multiple stations within a single city or region. Results show significant variations in the contributions of the various sources to aerosol concentrations within the city. They also suggest that the method may provide help in locating unknown sources.