大気エアロゾル中の炭素フラクションと¹⁴C分析

抄録

Abstract Radiocarbon (¹⁴C) is a powerful tracer for source apportionment of carbonaceous aerosols, because it can provide a measure for estimating the ratio of carbonaceous fraction from fossil and biomass/biogenic sources. To quantify ¹⁴C concentration not only for total carbon (TC), but also organic carbon (OC), elemental carbon (EC) and water-soluble OC (WSOC) in atmospheric aerosol, separation techniques of carbonaceous fractions have been investigated so far. This paper focuses on the methods for separating carbonaceous fractions and on the intercomparison of ¹⁴C concentration measurements of each carbonaceous fraction. Recent studies on the separation of OC and EC for ¹⁴C measurements have suggested the importance of 1) extraction of WSOC before thermal separation, 2) heating temperature for the removal of refractory OC, and 3) comparison of ¹⁴C concentrations in each fraction measured with different protocols. Direct measurements of ¹⁴C concentration in WSOC have also been reported. The measurements of ¹⁴C in carbonaceous fractions help revealing the carbonaceous sources and behaviors in environments.