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Global and Regional Impacts of HONO on the Chemical Composition of Clouds and AerosolsRecently, realistic simulation of nitrous acid (HONO) based on the HONO/NO(sub x) ratio of 0.02 was found to have a significant impact on the global budgets of HO(sub x) (OH + HO2) and gas phase oxidation products in polluted regions, especially in winter when other photolytic sources are of minor importance. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that simulating realistic HONO levels can significantly enhance aerosol sulphate (S(VI)) due to the increased formation of H2SO4. Even though in-cloud aqueous phase oxidation of dissolved SO2 (S(IV)) is the main source of S(VI), it appears that HONO related enhancement of H2O2 does not significantly affect sulphate because of the predominantly S(IV) limited conditions, except over eastern Asia. Nitrate is also increased via enhanced gaseous HNO3 formation and N2O5 hydrolysis on aerosol particles. Ammonium nitrate is enhanced in ammonia-rich regions but not under ammonia-limited conditions. Furthermore, particle number concentrations are also higher, accompanied by the transfer from hydrophobic to hydrophilic aerosol modes. This implies a significant impact on the particle lifetime and cloud nucleating properties. The HONO induced enhancements of all species studied are relatively strong in winter though negligible in summer. Simulating realistic HONO levels is found to improve the model measurement agreement of sulphate aerosols, most apparent over the US. Our results underscore the importance of HONO for the atmospheric oxidizing capacity and corroborate the central role of cloud chemical processing in S(IV) formation.
Document ID
20150001304
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Elshorbany, Y. F.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Crutzen, P. J.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Steil, B.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Pozzer, A.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Tost, H.
(Mainz Univ. Germany)
Lelieveld, J.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Date Acquired
February 3, 2015
Publication Date
February 3, 2014
Publication Information
Publication: Atmospheric Chemistry and Physics
Publisher: Copernicus Publications
Volume: 14
Issue: 2
Subject Category
Environment Pollution
Chemistry And Materials (General)
Report/Patent Number
GSFC-E-DAA-TN17891
Funding Number(s)
CONTRACT_GRANT: NNX12AD03A
Distribution Limits
Public
Copyright
Other
Keywords
HONO
atmospheric oxidizing
Global and regional impacts

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