TY - JOUR
T1 - Molecular characteristics of organic compositions in fresh and aged biomass burning aerosols
AU - Li, Jianjun
AU - Li, Jin
AU - Wang, Gehui
AU - Zhang, Ting
AU - Dai, Wenting
AU - Ho, Kin Fai
AU - Wang, Qiyuan
AU - Shao, Yue
AU - Wu, Can
AU - Li, Li
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/11/1
Y1 - 2020/11/1
N2 - Biomass burning (BB) is the most important source of primary organic aerosols (OA) in the atmosphere that has significant impact on local/regional air quality and human health. However, few studies paid attention to the evolution of molecular characteristics of BB OA in the atmospheric aging processes. In this study, both fresh and aged PM2.5 aerosols from burning of rice, maize, and wheat straws were collected from a combined system of combustion chamber and oxidation flow reactor, and were analyzed for >100 organic species. The emission factors (EFs) of anhydrosugars and some fatty acids showed slight variations between fresh and aged samples, indicating that these compounds are relatively stable. However, the EFs of n-alkanes, fatty alcohols, and parent-PAHs decreased 8–57% from fresh to aged samples, suggesting that they can undergo further oxidation to form other organic materials in the atmosphere. Phthalic acids, nitrophenols and isoprene-derived products were mainly secondarily formed by aging processes. Thus their EFs increased by 2–23 times from fresh to aged samples. Levoglucosan was the most abundant individual organic tracer, and its EF varied slightly between fresh and aged samples, proving its indicative role on BB emission. Moreover, the ratio of vanillic acid to levoglucosan and p-hydroxybenzoic acid to levoglucosan increased 2–13 times from fresh to aged samples. Therefore they can be used to investigate the impact of aging processes on BB aerosols in the atmosphere. RO2 + HO2 pathway derived 2-methyltetrols (2-MTs) predominated the EFs of isoprene-derived products (SOAi) in the fresh samples. However, RO2 + NO pathway derived 2-methylglyceric acid (2-MGA) increased by >30 times and became comparable with 2-MTs in aged particles. The ratio of 2-MGA/2-MTs increased from 0.06–0.27 in fresh samples to 0.94–1.18 in aged samples, because the high loading of NOx in BB smoke enhanced the formation of SOAi through RO2 + NO reactions.
AB - Biomass burning (BB) is the most important source of primary organic aerosols (OA) in the atmosphere that has significant impact on local/regional air quality and human health. However, few studies paid attention to the evolution of molecular characteristics of BB OA in the atmospheric aging processes. In this study, both fresh and aged PM2.5 aerosols from burning of rice, maize, and wheat straws were collected from a combined system of combustion chamber and oxidation flow reactor, and were analyzed for >100 organic species. The emission factors (EFs) of anhydrosugars and some fatty acids showed slight variations between fresh and aged samples, indicating that these compounds are relatively stable. However, the EFs of n-alkanes, fatty alcohols, and parent-PAHs decreased 8–57% from fresh to aged samples, suggesting that they can undergo further oxidation to form other organic materials in the atmosphere. Phthalic acids, nitrophenols and isoprene-derived products were mainly secondarily formed by aging processes. Thus their EFs increased by 2–23 times from fresh to aged samples. Levoglucosan was the most abundant individual organic tracer, and its EF varied slightly between fresh and aged samples, proving its indicative role on BB emission. Moreover, the ratio of vanillic acid to levoglucosan and p-hydroxybenzoic acid to levoglucosan increased 2–13 times from fresh to aged samples. Therefore they can be used to investigate the impact of aging processes on BB aerosols in the atmosphere. RO2 + HO2 pathway derived 2-methyltetrols (2-MTs) predominated the EFs of isoprene-derived products (SOAi) in the fresh samples. However, RO2 + NO pathway derived 2-methylglyceric acid (2-MGA) increased by >30 times and became comparable with 2-MTs in aged particles. The ratio of 2-MGA/2-MTs increased from 0.06–0.27 in fresh samples to 0.94–1.18 in aged samples, because the high loading of NOx in BB smoke enhanced the formation of SOAi through RO2 + NO reactions.
KW - Atmospheric aging
KW - Biomass burning
KW - Molecular composition
KW - Organic aerosol
UR - https://www.scopus.com/pages/publications/85086804834
U2 - 10.1016/j.scitotenv.2020.140247
DO - 10.1016/j.scitotenv.2020.140247
M3 - 文章
C2 - 32585482
AN - SCOPUS:85086804834
SN - 0048-9697
VL - 741
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 140247
ER -
