Measurements of Particulate Carbon Concentration and Estimation of Secondary Formation of Organic Particulate Matter in Ambient Air over the Tokyo Metropolitan Area

Abstract

Concentrations of organic carbon (C_ao) and Elemental carbon (C_ae) in ambient particulate matter were meas-ured over the Tokyo metropolitan area on July 23, 1982. The lowest and the highest concentrations of each carbon were appeared in early morning and midday time, respectively. The every peaks of [C_ao]/[C0], [C_ao]/[CH=CH] and [C_ao]/[C_ae] were appeared in midday time or late afternoon. The half part of C_ao measured in the daytime is estimated to be formed secondarily in the atmosphere from both the above ratios and gas-to-particle conversion of nonmethane hydrocarbons to organic particulate carbon.