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Title: Effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events

In this study, the effect of heterogeneous aqueous reactions on the secondary formation of inorganic aerosols during haze events was investigated by analysis of comprehensive measurements of aerosol composition and concentrations [e.g., particular matters (PM 2.5), nitrate (NO 3), sulfate (SO 4), ammonium (NH 4)], gas-phase precursors [e.g., nitrogen oxides (NOx), sulfur dioxide (SO 2), and ozone (O 3)], and relevant meteorological parameters [e.g., visibility and relative humidity (RH)]. The measurements were conducted in Beijing, China from Sep. 07, 2012 to Jan. 16, 2013. The results show that the conversion ratios of N from NOx to nitrate (N ratio) and S from SO 2 to sulfate (S ratio) both significantly increased in haze events, suggesting enhanced conversions from NOx and SO 2 to their corresponding particle phases in the late haze period. Further analysis shows that N ratio and S ratio increased with increasing RH, with N ratio and S ratio being only 0.04 and 0.03, respectively, when RH < 40%, and increasing up to 0.16 and 0.12 when RH reached 60–80%, respectively. The enhanced conversion ratios of N and S in the late haze period is likely due to heterogeneous aqueous reactions, because solar radiation and thus the photochemicalmore » capacity are reduced by the increases in aerosols and RH. This point was further affirmed by the relationships of N ratio and S ratio to O 3: the conversion ratios increase with decreasing O 3 concentration when O 3 concentration is lower than <15 ppb but increased with increasing O 3 when O 3 concentration is higher than 15 ppb. The results suggest that heterogeneous aqueous reactions likely changed aerosols and their precursors during the haze events: in the beginning of haze events, the precursor gases accumulated quickly due to high emission and low reaction rate; the occurrence of heterogeneous aqueous reactions in the late haze period, together with the accumulated high concentrations of precursor gases such as SO 2 and NOx, accelerated the formation of secondary inorganic aerosols, and led to rapid increase of the PM 2.5 concentration.« less
 [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [3] ;  [1]
  1. Beijing Key Lab. of Cloud, Beijing (China); Institute of Urban Meteorology, Beijing (China)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Beijing Key Lab. of Cloud, Beijing (China)
Publication Date:
Report Number(s):
Journal ID: ISSN 1352-2310; R&D Project: 2015-BNL-EE631EECA-Budg; KP1703020
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Atmospheric Environment (1994)
Additional Journal Information:
Journal Name: Atmospheric Environment (1994); Journal Volume: 122; Journal Issue: C; Journal ID: ISSN 1352-2310
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; Beijing hazes; heterogeneous aqueous reactions; inorganic aerosol; particles size
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1250933