 |
| Titel |
Impacts of aerosols on the chemistry of atmospheric trace gases: a case study of peroxides and HO2 radicals |
| VerfasserIn |
H. Liang, Z. M. Chen, D. Huang, Y. Zhao, Z. Y. Li |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 22 ; Nr. 13, no. 22 (2013-11-20), S.11259-11276 |
| Datensatznummer |
250085824
|
| Publikation (Nr.) |
 copernicus.org/acp-13-11259-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| Field measurements of atmospheric peroxides were obtained
during the summer on two consecutive years over urban Beijing, which highlighted the impacts of aerosols on the chemistry of peroxide compounds and
hydroperoxyl radicals (HO2). The major peroxides were determined to be
hydrogen peroxide (H2O2), methyl hydroperoxide (MHP), and
peroxyacetic acid (PAA). A negative correlation was found between
H2O2 and PAA in rainwater, providing evidence for a conversion
between H2O2 and PAA in the aqueous phase. A standard gas phase
chemistry model based on the NCAR Master Mechanism provided a good
reproduction of the observed H2O2 profile on non-haze days but
greatly overpredicted the H2O2 level on haze days. We attribute
this overprediction to the reactive uptake of HO2 by the aerosols,
since there was greatly enhanced aerosol loading and aerosol liquid water
content on haze days. The discrepancy between the observed and modeled
H2O2 can be diminished by adding to the model a newly proposed
transition metal ion catalytic mechanism of HO2 in aqueous aerosols.
This confirms the importance of the aerosol uptake of HO2 and the
subsequent aqueous phase reactions in the reduction of H2O2. The
closure of HO2 and H2O2 between the gas and aerosol phases
suggests that the aerosols do not have a net reactive uptake of
H2O2, because the conversion of HO2 to H2O2 on
aerosols compensates for the H2O2 loss. Laboratory studies for the
aerosol uptake of H2O2 in the presence of HO2 are urgently
required to better understand the aerosol uptake of H2O2 in the
real atmosphere. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|