Abstract
Abstract. Organic aerosol (OA) simulations using the volatility basis-set approach were made for East Asia and its outflow region. Model simulations were evaluated through comparisons with OA measured by aerosol mass spectrometers in and around Tokyo (at Komaba and Kisai in summer 2003 and 2004) and over the outflow region in East Asia (at Fukue and Hedo in spring 2009). The simulations with aging processes of organic vapors reproduced the mass concentrations, temporal variations, and formation efficiencies of observed OA at all of the sites reasonably well. As OA mass was severely underestimated in the simulations without the aging processes, the oxidations of organic vapors are essential for reasonable OA simulations over East Asia. By considering the aging processes, simulated OA concentrations increased from 0.24 to 1.28 μg m−3 in the boundary layer over the whole of East Asia. OA formed from the interaction of anthropogenic and biogenic sources was also enhanced by the aging processes. The fraction of controllable OA was estimated to be 87% of total OA over the whole of East Asia, which indicated that most of the OA in our simulations were formed anthropogenically (from controllable combustion sources). A large portion of biogenic secondary OA (78% of biogenic secondary OA) was formed through the influence of anthropogenic sources. These fractions were higher than the fraction of anthropogenic emissions. An important reason for these higher controllable fractions was higher oxidant concentrations and the resulting faster oxidation rates of OA precursors by considering anthropogenic sources. Both the amounts (from 0.18 to 1.12 μg m−3) and the fraction (from 75 to 87%) of controllable OA were increased by aging processes of organic vapors over East Asia.
Highlights
Organic aerosol (OA) accounts for a significant mass fraction of submicron aerosols in the atmosphere (Kanakidou et al, 2005; Zhang et al, 2007) and influences the Earth’s climate directly and indirectly (Hallquist et al, 2009)
These results show that the emissions of S / IVOCs and the oxidation processes of organic vapors (S / IVOCs and oxidized VOCs (OVOCs)) must be considered for reasonable OA simulations in and around Tokyo: including these in the volatility basis set (VBS) scheme considerably improved the model’s ability to simulate OA absolute concentrations and their temporal variations in Tokyo and its outflow area at Kisai
AN-aging is very important for OA formation from both anthropogenic and biogenic sources. These results show that biogenic SOA (BSOA) concentrations are substantially enhanced by OA models that can represent realistic OA concentrations from anthropogenic OA in the atmosphere, even if we do not change the treatment of BSOA formation processes in the model
Summary
Organic aerosol (OA) accounts for a significant mass fraction of submicron aerosols in the atmosphere (Kanakidou et al, 2005; Zhang et al, 2007) and influences the Earth’s climate directly (by scattering/absorption of solar radiation) and indirectly (by modifying cloud microphysical properties) (Hallquist et al, 2009). Few studies have focused on OA concentrations and their spatial distributions over the whole of East and Southeast Asia and its outflow region (Han et al, 2008; Jiang et al, 2012) They underestimated observed OA and/or SOA concentrations over China. As anthropogenic and biogenic emissions are both very large over East and Southeast Asia, the interaction of anthropogenic and biogenic sources and the resulting enhancement of BSOA are very important and should be examined for this region These understandings would be useful for estimating the past, current, and future OA concentrations and their regional and hemispherical climatic impacts. The objective of this study is to understand OA concentrations and their spatial distributions over East and Southeast Asia and its outflow region with the interaction of anthropogenic and biogenic sources.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
