Temporal variation of radiocarbon concentration in airborne particulate matter in Tokyo

Abstract

The temporal radiocarbon variation (in terms of percent Modern Carbon: pMC) of size-fractionated airborne particulate matter (APM) collected in Tokyo between April 2002 and February 2003 was analyzed in order to get an insight into the sources of carbonaceous particles. Results indicated significant biogenic origins (approximately 40 pMC on average). In general, the seasonal and particle size variations in pMC were relatively small, with 2 exceptions: elevated pMC in coarse particles in April and October 2002, and relatively low pMC in the finest particle size fraction collected in August 2002. The former finding could be tentatively attributed to the abundance of coarse particles of biological origins, such as pollen; the latter might be due to an increased fraction of anthropogenic secondary particles.