Abstract |
In October of 1976, aerosol particulate samples were collected while driving on Los Angeles freeways and were analyzed for sulfate, nitrate, and elemental composition. The measurements indicate that neither nitrate nor sulfate concentrations increased significantly over the roadway. The mean nitrate concentration in the fine particle fraction was 0.2 microgram/cu m and was not above the mean background value. The mean background sulfate concentration was 7.9 microgram/cu m, and the in-roadway sulfate increment was less than 1.5 microgram/cu m. However, the mean in-roadway lead concentration of 10.9 microgram/cu m exceeded the mean background value by a factor of more than 6. The optical attenuation of the collected aerosol deposits was measured: the mean in-roadway value exceeded the background value by a factor of 4. (Copyright (c) Pergamon Press Ltd., 1979.) |