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Chemical Differences Between PM 1 and PM 2.5 in Highly Polluted Environment and Implications in Air Pollution Studies
Author(s) -
Sun Yele,
He Yao,
Kuang Ye,
Xu Wanyun,
Song Shaojie,
Ma Nan,
Tao Jiangchuan,
Cheng Peng,
Wu Cheng,
Su Hang,
Cheng Yafang,
Xie Conghui,
Chen Chun,
Lei Lu,
Qiu Yanmei,
Fu Pingqing,
Croteau Philip,
Worsnop Douglas R.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl086288
Subject(s) - aerosol , relative humidity , environmental science , environmental chemistry , pollution , air pollution , atmospheric sciences , coal combustion products , chemical composition , particulates , combustion , particle (ecology) , chemistry , meteorology , geology , physics , ecology , organic chemistry , biology , oceanography
Submicron aerosol (PM 1 ) species measured by aerosol mass spectrometers have been widely used to validate chemical transport models; however, the uncertainties due to chemical differences between PM 1 and PM 2.5 are poorly constrained. Here we characterized such differences in a highly polluted environment in north China in winter. Our results showed that the changes in PM 1 /PM 2.5 ratios as a function of relative humidity (RH) were largely different for primary and secondary species. Secondary organic and inorganic aerosol (SOA and SIA) presented clear decreases in PM 1 /PM 2.5 ratios at RH > 60% during periods with high SIA contributions (>50%), likely driven by the changes in aerosol hygroscopicity and phase states, while the traffic and coal combustion OA had limited dependence on RH. Thermodynamic modeling showed negligible impacts of PM differences on predictions of particle acidity, yet these impacts can cause a difference in aerosol water content by up to 50–70%.