Seasonal Characteristics of Biogenic Secondary Organic Aerosols Over Chichijima Island in the Western North Pacific: Impact of Biomass Burning Activity in East Asia. Issue 12 (15th June 2021)

• Record Type: Journal Article
• Authors: Verma, Santosh Kumar; Kawamura, Kimitaka; Deshmukh, Dhananjay Kumar; Haque, Md. Mozammel; Pavuluri, Chandra Mouli
• Is Part Of: Journal of geophysical research. Volume 126:Issue 12(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-15
• Subjects: biogenic SOA tracers -- biomass burning -- continental influence -- remote marine aerosols; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2020JD032987
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: To better understand the formation processes of biogenic secondary organic aerosols (SOAs) over remote oceanic regions, aerosol samples were collected from 2010 to 2012 at Chichijima Island in the western North Pacific (WNP). The samples were analyzed by gas chromatography‐mass spectrometry for SOA tracers, which are produced by the photochemical oxidation of biogenic volatile organic compounds (BVOCs), including isoprene, monoterpenes, and sesquitepenes. Although no seasonal trend was identified for the isoprene‐derived SOA tracers, we observed higher levels of the monoterpene‐derived and sesquiterpene‐derived SOA tracers in winter/spring and lower levels in summer/autumn. We found a significant correlation ( r = 0.87) of β ‐caryophyllinic acid with levoglucosan, the latter being a specific tracer of biomass burning (BB). This suggests that the β ‐caryophyllene accumulated in higher plants is evaporated by BB followed by atmospheric oxidation during long‐range transport from the Asian continent over the WNP. The biogenic secondary organic carbon concentration estimated using a tracer‐based approach ranged from 0.11 to 174 ngC m −3 (avg. 34.8 ± 38.2 ngC m −3 ), accounting for 0.02%–32.0% (avg. 6.11% ± 6.42%) of the measured organic carbon. Our results indicate that SOAs are formed by the photooxidation of BVOCs. The backward trajectories of air masses further support their transport from the central Pacific during mid‐spring to mid‐autumn, whereas BB aerosols are transported from the Asian continent during mid‐autumn to mid‐spring over the WNP. Positive matrix factorization analyses of the SOA tracers suggest that organic aerosols of Chichijima are mostly related to BVOC emissions, with BB's additional contributions especially in winter and spring. Key Points: Monoterpene SOA tracers are significant sources for BSOAs, followed by isoprene and β‐caryophyllene SOA tracers in Chichijima aerosols High‐NOx BSOA tracers (2‐MGA, 3‐HGA, and 3‐MBTCA) are influenced by the long‐range transport of anthropogenic air masses from East Asia Low‐NOx BSOA tracers (2‐MTLs and C5 ‐alkenetriols) are produced mainly by the oxidation of locally emitted isoprene