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| Titel |
Megacity ozone air quality under four alternative future scenarios |
| VerfasserIn |
T. M. Butler, Z. S. Stock, M. R. Russo, H. A. C. Denier van der Gon, M. G. Lawrence |
| 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 |
250060084
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| Zusammenfassung |
| The impact of the megacities of the world on global tropospheric ozone, and conversely, the
extent to which megacities are influenced by emissios of ozone precursors from outside of the
megacities is examined under the four alternative RCP (“Representative Concentration
Pathway”) emissions scenarios. Despite accounting for about 6% of present-day
anthropogenic emissions of ozone precursor species, the contribution of emissions from
megacities to global tropospheric ozone is calculated to be 0.84%. By 2100 this
contribution falls to between 0.18% and 0.62% depending on the scenario, with the
lower value being for the most-polluting of the four future emissions scenarios due
to stringent controls on ozone precursor emissions from highly populated areas
combined with a stronger tropospheric background ozone field. The higher end of
this range is from the least-polluting of the four emissions scenarios, due lower
background tropospheric ozone combined with the use of a different downscaling
methodology in the construction of the scenario. Although the absolute impact
of megacities on global ozone is small, an important result of this study is that
under all future scenarios, future air quality in megacities is expected to be less
influenced by local emissions within the cities, but instead more influenced by
emission sources outside of the cities. Air quality trends in the megacities of the
developing world are projected to be similar to observed trends in developed world
megacities over the last few decades. Assumptions made when downscaling the
emissions scenarios onto the grids used in such modelling studies can have a large
influence on these results. Future work should concentrate on the creation of spatially
explicit scenarios of urban development for use in global chemical transport models. |
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