The ambient air quality limit value for NO2 for the year 2010 is currently exceeded in many busy streets in Europe. Despite the reductions of NO(x) emissions, the concentrations of NO2 have hardly decreased in the past years; increases have been observed at some traffic sites. Causes for the development of NO2 concentrations in streets in Germany are primarily the increase of primary NO2 emissions from modern diesel passenger cars and in addition their increased mileage share. NO2 formation by atmospheric chemical reactions of emitted NO still has a considerable share on NO2 concentrations in streets, though. Results of new projects in Germany give a clearer picture of the reasons for high NO2 concentrations in streets and the effectiveness of reduction measures. The contribution of primary NO2 emissions and atmospheric chemical NO2 formation to NO2 air pollution was analysed with several methods for a busy major street in the city of Stuttgart. The impact of more stringent exhaust emission limits on future air quality was calculated by using a chemical box model. At the analysed location, the future NO2 limit value can only be met with a considerable reduction of primary NO2 exhaust emissions from vehicles in addition with reduction of atmospheric chemical NO2 formation in the street and in the urban background.
High NO2 concentrations in urban streets - causes and impact of measures
2008
10 Seiten, 13 Bilder, 12 Quellen
Aufsatz (Konferenz)
Englisch
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