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| Titel |
Contribution of local sources to Megacities air quality |
| VerfasserIn |
A. G. Megaritis, C. Fountoukis, S. N. Pandis, The MEGAPOLI Team |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250058715
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| Zusammenfassung |
| Abstract
The ongoing urbanization over the past decades has led to an increasing number of large
urban agglomerations around the world, now hosting more than half of the world’s population
(UN 2007). These large urban areas with more than 10 million inhabitants, also known as
Megacities (Gurjar and Lelieveld 2005) are substantial sources of anthropogenic pollutants
having adverse effects on human health, visibility and ecosystems. Development of
emissions control strategies to improve Megacities air quality requires quantification
of the fraction of the pollution originating from local and regional sources and to
determine to which extent Megacities emissions influence the air quality of surrounding
areas.
PMCAMx-2008 (Murphy and Pandis, 2009; Fountoukis et al., 2011), a three dimensional
chemical transport model (CTM) was applied in Europe, to quantify the influence of
emissions in European Megacities (Paris, London, Rhine-Ruhr, PoValley) on the
concentration of the major PM2.5 components. Different emissions scenarios were applied
(e.g. an “annihilation” scenario zeroing all anthropogenic emissions in Megacities), and the
impact of Megacities emissions on air quality within Megacities and also their contribution
on the air quality in the surrounding regions was investigated. Two simulation periods were
used, summer 2009 and winter 2010, to study the seasonal effect of Megacities
emissions.
The results show that the impact of the local emissions on the concentration of
total PM2.5within Megacities is quite variable in space and time. In Po Valley, total
PM2.5was found to be largely local in both periods (over 50% in summer and more
than 60% during winter), while in Paris and Rhine-Ruhr the contribution of local
sources is significant mainly during winter. On the contrary, London emissions
have a much smaller effect on local PM2.5 and long range transport of pollutants
dominates.
Megacities emissions are important for local black carbon (BC) levels. In both
periods BC is found to originate from local sources in all the Megacities (more than
40%), while in Po Valley local sources accounted for approximately 90% of BC.
Sulfate and secondary organics concentrations on the other hand are dominated by
sources outside the major urban areas. At the same time, Megacities do not only
influence their own air quality, but they also impact areas several hundred kilometres
away.
References
Fountoukis C., Racherla P. N., Denier van der Gon H. A. C., Polymeneas P.,
Charalampidis P. E., Pilinis C., Wiedensohler A., Dall’Osto M., O’Dowd C., and S. N. Pandis
(2011) Evaluation of a three-dimensional chemical transport model (PMCAMx) in the
European domain during the EUCAARI May 2008 campaign, Atmos. Chem. Phys., 11,
10331-10347.
Gurjar B. R., Lelieveld J, (2005) New directions: megacities and global change. Atmos.
Environ., 39, 391-393
Murphy B. N. and S. N. Pandis (2009) Simulating the formation of semivolatile primary
and secondary aerosol in a regional chemical transport model, Environ. Sci. Tech., 43,
4722-4728.
United Nations Population Fund, UNFPA, State of the world population (2007) Unleashing
the potential of urban growth, available at: http://www.unfpa.org/swp/2007/presskit/pdf/
sowp2007 eng.pdf. |
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