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| Titel |
Observation of atmospheric aerosols at Mt. Hua and Mt. Tai in central and east China during spring 2009 – Part 1: EC, OC and inorganic ions |
| VerfasserIn |
G. Wang, J. Li, C. Cheng, S. Hu, M. Xie, S. Gao, B. Zhou, W. Dai, J. Cao, Z. An |
| 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. 9 ; Nr. 11, no. 9 (2011-05-06), S.4221-4235 |
| Datensatznummer |
250009700
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| Publikation (Nr.) |
 copernicus.org/acp-11-4221-2011.pdf |
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| Zusammenfassung |
PM10 and size-segregated samples were simultaneously collected at Mt. Hua (2060 m a.s.l.) and Mt. Tai (1545 m a.s.l.) in central and east coastal
China during spring, 2009 including an intensive dust storm event occurring
on 24 April, and determined for EC, OC and inorganic ions. During the
non-dust storm period particles, EC, OC and ions except for SO42−
were 2–10 times more abundant at Mt. Tai than at Mt. Hua. SO42− (13 ± 7.1 μg m−3) at Mt. Hua was the dominant ion,
followed by NO3− (5.0 ± 3.9 μg m−3),
NH4+ (2.5 ± 1.3 μg m−3) and Ca2+ (1.6 ± 0.8 μg m−3). In contrast, at Mt. Tai NO3− was most
abundant (20 ± 14 μg m−3), followed by SO42−
(16 ± 13 μg m−3), NH4+ (12 ± 8.9 μg m−3) and Ca2+ (3.9 ± 2.1 μg m−3). The
fact of NO3− exceeding over SO42− at Mt. Tai may suggest
the changes in chemical composition of the atmosphere over east China due to
sharply increasing vehicle emission. pH values of the water-extracts of
PM10 samples indicate that at the two mountain sites aerosols
transported from the south regions are more acidic than those from the north
and more acidic at Mt. Tai than at Mt. Hua during the non-dust storm period.
During the dust storm event particle mass, OC, Na+, K+, Mg2+
and Ca2+ at both sites increased by a factor of 1–9, while EC,
NO3− and NH4+ decreased by 20–80 %. However,
SO42− concentrations (13 ± 7.7 μg m−3 at Mt. Hua and 15 ± 5.6 μg m−3 at Mt. Tai, respectively) at the two
sites during the episode were comparable and did not change significantly
compared to those in the non-dust storm period, probably due to a similar
level of free tropospheric SO2 in central and east China.
Compared with those at Mt. Hua the coarse modes (>2.1 μm) of K+ and
SO42− at Mt. Tai during the non-event period were more abundant
and the coarse mode of NO3− was less abundant. When the dust storm
was present all ions significantly moved toward coarse particles, except for
NH4+, with a disappeared peak in fine mode (<2.1 μm) for NO3−.
Linear regression for ion equivalents in fine particles indicates that
ammonium exists in the forms of NH4NO3 and NH4HSO4 at
Mt. Hua and NH4NO3 and (NH4)2SO4 at Mt. Tai during
both the nonevent and the event periods. While the regression for coarse
mode of Ca2+ suggests a close coupling of dust with nitrate during the
nonevent time and with sulfate during the dust-storm period. pH values of
the size-resolved samples further suggest that during the nonevent period
most acidic particles at Mt. Hua are in the range of 0.7–1.1 μm, while
those at Mt. Tai are in the range of 1.1–2.1 μm. Aerosols at both sites
became alkaline during the event, but the Mt. Tai particles still showed a
lower pH value. |
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