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Titel |
Seasonal variation of ozone and black carbon observed at Paknajol, an urban area in the Kathmandu Valley, Nepal |
VerfasserIn |
Davide Putero, Paolo Cristofanelli, Angela Marinoni, Bhupesh Adhikary, Rocco Duchi, Sunil Das Shrestha, Gian Pietro Verza, Tony Christian Landi, Francescopiero Calzolari, Maurizio Busetto, Giacomo Agrillo, Fabio Biancofiore, Piero Di Carlo, Arnico Panday, Maheswar Rupakheti, Paolo Bonasoni |
Konferenz |
EGU General Assembly 2016
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Medientyp |
Artikel
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Sprache |
en
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 18 (2016) |
Datensatznummer |
250133412
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Publikation (Nr.) |
EGU/EGU2016-14021.pdf |
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Zusammenfassung |
The Kathmandu Valley in the Himalayan foothills, considered as one of the global “hot
spots” for what concerns air pollution, is currently facing severe air quality problems
due to rapid urbanization processes, dramatic land use changes, socioeconomic
transformation and high population growth. In this work, we present the first full year
(February 2013 – February 2014) analysis of simultaneous measurements of two
short-lived climate forcers/pollutants (SLCF/P), i.e. ozone (O3) and equivalent
black carbon (BC), and aerosol number concentration at Paknajol (27∘43′4′′ N,
85∘18′32′′ E, 1380 m a.s.l.), in the city center of Kathmandu. These observations were
carried out in the framework of the SusKat-ABC (A Sustainable Atmosphere for the
Kathmandu Valley – Atmospheric Brown Cloud) campaign in Nepal. The diurnal
behavior of BC and aerosol number concentration indicated that local pollution
sources represent the major contribution to air pollution in this city. In addition to
photochemistry, the planetary boundary layer (PBL) dynamic plays an important role in
determining O3 variability, as suggested by the analysis of seasonal changes of
the diurnal cycles and the correlation with meteorological parameters and aerosol
properties. Especially during pre-monsoon, high values of O3 were observed during
the afternoon/evening. This could be related to mixing and entrainment processes
between upper residual layers and the PBL. During this season, the high O3 appeared
well related to the impact of major open vegetation fires occurring in Nepal. On a
synoptic-scale perspective, westerly and regional atmospheric circulations appeared
to be especially conducive for the occurrence of the high BC and O3 values. The
very high values of the SLCF/P, detected during the whole measurement period,
indicated persisting adverse air quality conditions, dangerous for the health of over 3
million residents of the Kathmandu Valley, and the environment. Consequently, all of
this information may be useful for implementing control measures to mitigate the
occurrence of acute pollution levels in the Kathmandu Valley and the surrounding area. |
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