Abstract Number: 681 Working Group: Remote and Regional Atmospheric Aerosols
Abstract One of the least understood characteristics of aerosols is the source and contribution of the organics. Our recent observation revealed that submicron aerosol particles in Northeast Asia have a variable but relatively high mass fraction (approximately 50%) of carbonaceous matter throughout the year. In order to investigate on their source and transport pathways, we analyzed the radio carbon isotope (14C) concentration within fine carbonaceous particles.
We collected weekly PM2.5 samples at NOTO Ground-based Research Observatory (NOTOGRO, 37.45ºN, 137.36ºE) from 26th Jun, 2014 to 17th June, 2015. The analysis of 14C was conducted using AMS 14C system (High Voltage Engineering Europe, Model 4130-AMS). In addition, the other parameters including concentrations of specific organic compounds, stable carbon isotope (δ13C), black carbon, PM2.5 and back trajectory analysis were combined to better constrain the carbon sources.
The results showed that contribution of carbonaceous matter originating from fossil fuel burning is generally small (30 pMC; percent modern carbon), whereas that from modern biological activity and/or biomass burning is large (70 pMC). Concentration of 14C in autumn samples were the highest in all seasons (90 pMC), and there were indications that large scale agricultural waste burning in Northeast China is the likely source. The lowest 14C concentrations in winter samples (55 pMC) can be linked to combustion of fossil fuel for domestic heating and little biological activity. In summer, active secondary organic aerosol formation was suggested, but a sporadic peak of modern carbon was observed which can be attributed to the plume from Siberian forest fire.