Real-time measurement of the size fractionation of aerosol black carbon during the South Coast Air Quality Study, June 13--September 4, 1987, Claremont College, Claremont, California: Final report: Revision

Abstract

During the periods June 13 to July 28 and August 17 to September 4, 1987, the Atmospheric Aerosol Group of Lawrence Berkeley Laboratory participated in the South Coast Air Quality Study conducted at Claremont College, Claremont, California. We used a multi-channel aethalomether preceded by size-selective inlets to determine the concentration of aerosol black carbon in two size ranges in real time. In this report we present our results from this study in the form of one-hour and periodic (typically 12-hour) averages of carbon concentrations for the total suspended aerosol and for the fraction having aerodynamic diameter smaller than approximately 0.3 ..mu..m. The total concentration results show daily mean values generally ranging from 1 to 4 ..mu..g/m/sup 3/, with a diurnal cycle showing little variation during nighttime hours and a pronounced peak between the hours of 8 am and 10 am. The results for the size fractionation show that the great majority of the aerosol black carbon was found in the size range smaller than 0.3 ..mu..m: however, this fraction showed a systematic diurnal variation with a decline in the morning and the mid-day periods. 13 refs., 26 figs., 9 tabs.