GAW Report No. 205 - IGAC Project

CHAPTER 6 - EUROPEfrom the global inventories versus 1324 Gg(CO)/yr from the study of Gurjar et al. [2008]. A muchsmaller but still highly uncertain CO source is estimated for Istanbul (244-602 Gg(CO)/yr from theglobal inventories, with no city-specific inventory available). The discrepancies between thedatasets for NO X and NMHCs tend to be even larger. This large uncertainty – even for EuropeanMegacities, which should be among the best characterized around the world – points towards thelarge difficulty which will be inherent in assessing the role of megacities in regional and globalatmospheric pollution and climate change, and ascertaining effective mitigation strategies. On theother hand, despite the large differences in the totals, there is a notable similarity in thecharacteristics of the relative importance of various sectors for different gases. In particular, similarto most OECD nations, the emissions of CO are generally dominated by road transport, and of NO Xand NMHC by a combination of road transport and industrial processes, contrasted with the largerole of residential biofuel use for emissions from non-OECD countries.Figure 2 - (a) CO emissions for theyear 2000 based on the EDGARv3.2FT2000 database. (b) NOX emissionsfor the year 2000 based on theEDGARv3.2 FT2000 database. (c) SO2emissions for the year 2000 basedon the EDGARv3.2 FT2000 database195