TY - JOUR
T1 - Distinctions in source regions and formation mechanisms of secondary aerosol in Beijing from summer to winter
AU - Duan, Jing
AU - Huang, Ru-Jin
AU - Lin, Chunshui
AU - Dai, Wenting
AU - Wang, Meng
AU - Gu, Yifang
AU - Wang, Ying
AU - Zhong, Haobin
AU - Zheng, Yan
AU - Ni, Haiyan
AU - Dusek, Uli
AU - Chen, Yang
AU - Li, Yongjie
AU - Chen, Qi
AU - Worsnop, Douglas R.
AU - O'Dowd, Colin D.
AU - Cao, Junji
PY - 2019/8/14
Y1 - 2019/8/14
N2 - To investigate the sources and evolution of haze pollution in different seasons, long-term (from 15 August to 4 December 2015) variations in chemical composition of PM1 were characterized in Beijing, China. Positive matrix factorization (PMF) analysis with a multi-linear engine (ME-2) resolved three primary and two secondary organic aerosol (OA) sources, including hydrocarbon-like OA (HOA), cooking OA (COA), coal combustion OA (CCOA), local secondary OA (LSOA) and regional SOA (RSOA). The sulfate source region analysis implies that sulfate was mainly transported at a large regional scale in late summer, while local and/or nearby sulfate formation may be more important in winter. Meanwhile, distinctly different correlations between sulfate and RSOA or LSOA (i.e., better correlation with RSOA in late summer, similar correlations with RSOA and LSOA in autumn, and close correlation with LSOA in early winter) confirmed the regional characteristic of RSOA and local property of LSOA. Secondary aerosol species including secondary inorganic aerosol (SIA - sulfate, nitrate, and ammonium) and SOA (LSOA and RSOA) dominated PM1 during all three seasons. In particular, SOA contributed 46% to total PM1 (with 31% as RSOA) in late summer, whereas SIA contributed 41% and 45% to total PM1 in autumn and early winter, respectively. Enhanced contributions of secondary species (66 %-76% of PM1) were also observed in pollution episodes during all three seasons, further emphasizing the importance of secondary formation processes in haze pollution in Beijing. Combining chemical composition and meteorological data, our analyses suggest that both photochemical oxidation and aqueous-phase processing played important roles in SOA formation during all three seasons, while for sulfate formation, gas-phase photochemical oxidation was the major pathway in late summer, aqueous-phase reactions were more responsible during early winter and both processes had contributions during autumn.
AB - To investigate the sources and evolution of haze pollution in different seasons, long-term (from 15 August to 4 December 2015) variations in chemical composition of PM1 were characterized in Beijing, China. Positive matrix factorization (PMF) analysis with a multi-linear engine (ME-2) resolved three primary and two secondary organic aerosol (OA) sources, including hydrocarbon-like OA (HOA), cooking OA (COA), coal combustion OA (CCOA), local secondary OA (LSOA) and regional SOA (RSOA). The sulfate source region analysis implies that sulfate was mainly transported at a large regional scale in late summer, while local and/or nearby sulfate formation may be more important in winter. Meanwhile, distinctly different correlations between sulfate and RSOA or LSOA (i.e., better correlation with RSOA in late summer, similar correlations with RSOA and LSOA in autumn, and close correlation with LSOA in early winter) confirmed the regional characteristic of RSOA and local property of LSOA. Secondary aerosol species including secondary inorganic aerosol (SIA - sulfate, nitrate, and ammonium) and SOA (LSOA and RSOA) dominated PM1 during all three seasons. In particular, SOA contributed 46% to total PM1 (with 31% as RSOA) in late summer, whereas SIA contributed 41% and 45% to total PM1 in autumn and early winter, respectively. Enhanced contributions of secondary species (66 %-76% of PM1) were also observed in pollution episodes during all three seasons, further emphasizing the importance of secondary formation processes in haze pollution in Beijing. Combining chemical composition and meteorological data, our analyses suggest that both photochemical oxidation and aqueous-phase processing played important roles in SOA formation during all three seasons, while for sulfate formation, gas-phase photochemical oxidation was the major pathway in late summer, aqueous-phase reactions were more responsible during early winter and both processes had contributions during autumn.
KW - POSITIVE MATRIX FACTORIZATION
KW - RESOLVED CHEMICAL-CHARACTERIZATION
KW - SOURCE APPORTIONMENT
KW - ORGANIC AEROSOL
KW - HIGH-RESOLUTION
KW - SEASONAL-VARIATIONS
KW - SPECIATION MONITOR
KW - FINE PARTICLES
KW - HAZE POLLUTION
KW - AIR-POLLUTION
U2 - 10.5194/acp-19-10319-2019
DO - 10.5194/acp-19-10319-2019
M3 - Article
SN - 1680-7316
VL - 19
SP - 10319
EP - 10334
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 15
ER -