Loadings, Size Distributions, and Sources of Compound Classes in Los Angeles Aerosol

A low-pressure impactor, equipped with ZnSe impaction substrates, was used to sample ambient Los Angeles aerosol. This new approach to aerosol characterization provides size-resolved data on the loadings of organic and inorganic compound classes. The loadings and size distributions of sulfate, nitrate, aliphatic carbon, carbonyl, and organonitrate groups were determined and were used to investigate the sources of these aerosol components. The source resolution studies revealed that secondary aerosol formation processes contribute significantly to the loadings of several aerosol compound classes.