TY - JOUR
T1 - Unexpected quenching effect on new particle formation from the atmospheric reaction of methanol with SO3
AU - Liu, Ling
AU - Zhong, Jie
AU - Vehkamäki, Hanna
AU - Kurtén, Theo
AU - Du, Lin
AU - Zhang, Xiuhui
AU - Francisco, Joseph S.
AU - Zeng, Xiao Cheng
N1 - Funding Information:
ACKNOWLEDGMENTS. X.Z. and L.D. are indebted to the National Natural Science Foundation of China (Grants 21976015 and 91644214) for the support of this research. L.L. thanks China Scholarship Council. T.K. thanks the Academy of Finland for funding. H.V. thanks the European Research Council (Grant 692891-DAMOCLES) and the University of Helsinki, Faculty of Science ATMATH project for funding. J.S.F. and X.C.Z. acknowledge the computation support of University of Nebraska Holland Computing Center.
Funding Information:
X.Z. and L.D. are indebted to the National Natural Science Foundation of China (Grants 21976015 and 91644214) for the support of this research. L.L. thanks China Scholarship Council. T.K. thanks the Academy of Finland for funding. H.V. thanks the European Research Council (Grant 692891-DAMOCLES) and the University of Helsinki, Faculty of Science ATMATH project for funding. J.S.F. and X.C.Z. acknowledge the computation support of University of Nebraska Holland Computing Center.
Publisher Copyright:
© 2019 National Academy of Sciences. All rights reserved.
PY - 2019/12/10
Y1 - 2019/12/10
N2 - Despite the high abundance in the atmosphere, alcohols in general and methanol in particular are believed to play a small role in atmospheric new particle formation (NPF) largely due to the weak binding abilities of alcohols with the major nucleation precursors, e.g., sulfuric acid (SA) and dimethylamine (DMA). Herein, we identify a catalytic reaction that was previously overlooked, namely, the reaction between methanol and SO3, catalyzed by SA, DMA, or water. We found that alcohols can have unexpected quenching effects on the NPF process, particularly in dry and highly polluted regions with high concentrations of alcohols. Specifically, the catalytic reaction between methanol and SO3 can convert methanol into a less-volatile species––methyl hydrogen sulfate (MHS). The latter was initially thought to be a good nucleation agent for NPF. However, our simulation results suggest that the formation of MHS consumes an appreciable amount of atmospheric SO3, disfavoring further reactions of SO3 with H2O. Indeed, we found that MHS formation can cause a reduction of SA concentration up to 87%, whereas the nucleation ability of MHS toward new particles is not as good as that of SA. Hence, a high abundance of methanol in the atmosphere can lower the particle nucleation rate by as much as two orders of magnitude. Such a quenching effect suggests that the recently identified catalytic reactions between alcohols and SO3 need to be considered in atmospheric modeling in order to predict SA concentration from SO2, while also account for their potentially negative effect on NPF.
AB - Despite the high abundance in the atmosphere, alcohols in general and methanol in particular are believed to play a small role in atmospheric new particle formation (NPF) largely due to the weak binding abilities of alcohols with the major nucleation precursors, e.g., sulfuric acid (SA) and dimethylamine (DMA). Herein, we identify a catalytic reaction that was previously overlooked, namely, the reaction between methanol and SO3, catalyzed by SA, DMA, or water. We found that alcohols can have unexpected quenching effects on the NPF process, particularly in dry and highly polluted regions with high concentrations of alcohols. Specifically, the catalytic reaction between methanol and SO3 can convert methanol into a less-volatile species––methyl hydrogen sulfate (MHS). The latter was initially thought to be a good nucleation agent for NPF. However, our simulation results suggest that the formation of MHS consumes an appreciable amount of atmospheric SO3, disfavoring further reactions of SO3 with H2O. Indeed, we found that MHS formation can cause a reduction of SA concentration up to 87%, whereas the nucleation ability of MHS toward new particles is not as good as that of SA. Hence, a high abundance of methanol in the atmosphere can lower the particle nucleation rate by as much as two orders of magnitude. Such a quenching effect suggests that the recently identified catalytic reactions between alcohols and SO3 need to be considered in atmospheric modeling in order to predict SA concentration from SO2, while also account for their potentially negative effect on NPF.
KW - Alcohols
KW - Atmospheric aerosol
KW - Catalytic reactions
KW - Nucleation precursors
KW - SO
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U2 - 10.1073/pnas.1915459116
DO - 10.1073/pnas.1915459116
M3 - Article
C2 - 31767772
AN - SCOPUS:85076248535
SN - 0027-8424
VL - 116
SP - 24966
EP - 24971
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 50
ER -