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| Titel |
Heterogeneous reaction of peroxyacetic acid and hydrogen peroxide on ambient aerosol particles under dry and humid conditions: kinetics, mechanism and implications |
| VerfasserIn |
Q. Q. Wu, L. B. Huang, H. Liang, Y. Zhao, D. Huang, Z. M. Chen |
| 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 ; 15, no. 12 ; Nr. 15, no. 12 (2015-06-23), S.6851-6866 |
| Datensatznummer |
250119845
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| Publikation (Nr.) |
 copernicus.org/acp-15-6851-2015.pdf |
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| Zusammenfassung |
| Hydrogen peroxide (H2O2) and organic peroxides play important roles
in the cycle of oxidants and the formation of secondary aerosols in the
atmosphere. Recent field observations have suggested that the budget of
peroxyacetic acid (PAA, CH3C(O)OOH) is potentially related to the
aerosol phase processes, especially to secondary aerosol formation. Here, we
present the first laboratory measurements of the uptake coefficient of
gaseous PAA and H2O2 onto ambient fine particulate matter
(PM2.5) as a function of relative humidity (RH) at 298 K. The results
show that the PM2.5, which was collected in an urban area, can take up
PAA and H2O2 at the uptake coefficient (γ) of 10−4,
and both γPAA and γH2O2 increase
with increasing RH. The value of γPAA at 90 % RH is
5.4 ± 1.9 times that at 3 % RH, whereas
γH2O2 at 90 % RH is 2.4 ± 0.5 times that
at 3 % RH, which suggests that PAA is more sensitive to the RH variation
than H2O2 is. Considering the larger Henry's law constant of
H2O2 than that of PAA, the smaller RH sensitivity of the
H2O2 uptake coefficient suggests that the enhanced uptake of
peroxide compounds on PM2.5 under humid conditions is dominated by
chemical processes rather than dissolution. Considering that mineral dust is
one of the main components of PM2.5 in Beijing, we also determined the
uptake coefficients of gaseous PAA and H2O2 on authentic Asian Dust
storm (ADS) and Arizona Test Dust (ATD) particles. Compared to ambient
PM2.5, ADS shows a similar γ value and RH dependence in its
uptake coefficient for PAA and H2O2, while ATD gives a negative
dependence on RH. The present study indicates that, in addition to the
mineral dust in PM2.5, other components (e.g., soluble inorganic salts)
are also important to the uptake of peroxide compounds. When the
heterogeneous reaction of PAA on PM2.5 is considered, its atmospheric
lifetime is estimated to be 3.0 h on haze days and 7.1 h on non-haze days,
values that are in good agreement with the field observations. |
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