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| Titel |
Measurements of gaseous H₂SO₄ by AP-ID-CIMS during CAREBeijing 2008 Campaign |
| VerfasserIn |
J. Zheng, M. Hu, R. Zhang, D. Yue, Z. Wang, S. Guo, X. Li, B. Bohn, M. Shao, L. He, X. Huang, A. Wiedensohler, T. Zhu |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 15 ; Nr. 11, no. 15 (2011-08-03), S.7755-7765 |
| Datensatznummer |
250009974
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| Publikation (Nr.) |
 copernicus.org/acp-11-7755-2011.pdf |
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| Zusammenfassung |
| As part of the 2008 Campaign of Air Quality Research in
Beijing and Surrounding Regions (CAREBeijing 2008), measurements of gaseous
sulfuric acid (H2SO4) have been conducted at an urban site in
Beijing, China from 7 July to 25 September 2008 using atmospheric pressure
ion drift – chemical ionization mass spectrometry (AP-ID-CIMS). This
represents the first gaseous H2SO4 measurements in China. Diurnal
profile of sulfuric acid is strongly dependent on the actinic flux, reaching
a daily maximum around noontime and with an hourly average concentration of
5 × 106 molecules cm−3. Simulation of sulfuric acid on the
basis of the measured sulfur dioxide concentration, photolysis rates of
ozone and nitrogen dioxide, and aerosol surface areas captures the trend of
the measured H2SO4 diurnal variation within the uncertainties,
indicating that photochemical production and condensation onto preexisting
particle surface dominate the observed diurnal H2SO4 profile. The
frequency of the peak H2SO4 concentration exceeding
5 × 106 molecules cm−3 increases by 16 % during the period of the
summer Olympic Games (8–24 August 2008), because of the implementation of
air quality control regulations. Using a multivariate statistical method,
the critical nucleus during nucleation events is inferred, containing two
H2SO4 molecules (R2 = 0.85). The calculated condensation rate
of H2SO4 can only account for 10–25 % of PM1 sulfate
formation, indicating that either much stronger sulfate production exists at
the SO2 source region or other sulfate production mechanisms are
responsible for the sulfate production. |
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