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| Titel |
Effect of the summer monsoon on aerosols at two measurement stations in Northern India – Part 1: PM and BC concentrations |
| VerfasserIn |
A.-P. Hyvärinen, T. Raatikainen, D. Brus, M. Komppula, T. S. Panwar, R. K. Hooda, V. P. Sharma, H. Lihavainen |
| 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. 16 ; Nr. 11, no. 16 (2011-08-15), S.8271-8282 |
| Datensatznummer |
250010003
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| Publikation (Nr.) |
 copernicus.org/acp-11-8271-2011.pdf |
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| Zusammenfassung |
| Particulate matter (PM) and equivalent black carbon (BCe) concentrations were
measured at two locations in northern India during 2006–2010. The first
measurement station was a background site in Mukteshwar, about 350 km
northeast of New Delhi, in the foothills of the Indian Himalayas. The second
measurement site was located in Gual Pahari, about 25 km south of New Delhi.
Here we focused on resolving the effects of the Indian summer monsoon on the
particulate matter and equivalent black carbon concentrations at two
stations. The average monsoon time concentrations were decreased by
55–70 % compared to the pre-monsoon average concentrations at both
stations, decreasing as a function of the total local rainfall during the
monsoon season. In Mukteshwar during the monsoon, the 24 h PM2.5
concentrations were nearly always below the Indian National Air Quality
Standard of 60 μg m−3. In Gual Pahari, 13 % of days
exceeded this level during the monsoon season. However, the 24 h guideline
of 25 μg m−3 given by the World Health Organization was more
difficult to meet. In addition to loss processes, aerosol concentrations
during the early monsoon were found to be affected by primary emissions, most
likely from dust events
from the Thar Desert. This resulted in elevated fractions of the coarse mode,
PM2.5–10 at both stations. In Mukteshwar, additional dust contribution
came from east of the station, from the Himalayan region. We also determined
the characteristic transition times between the pre-monsoon, monsoon and
post-monsoon. The onset and withdrawal transitions occurred faster in
Mukteshwar than in Gual Pahari, both being typically less than 10 days.
Transition periods in Gual Pahari took between 17 and 31 days. The shorter
transition times in Mukteshwar were probably related to the more intense
rains due to the mountain location, and the fact that the station was most of
the time in the free troposphere. |
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