The impact of aviation emissions to urban air quality in Europe – Detailed airport-city analysis
Report no. 10/23:
Aviation causes emissions of NOx, SO2 and PM that have a negative impact on air quality. To investigate the extent of this impact, simulations with the chemical transport model (CTM) LOTOS-EUROS (LE) have been performed to model the atmospheric concentrations of NO2, SO2, PM10 and PM2.5 in 2018. The concentrations of these pollutants were simulated for six cities in Europe (London, Paris, Amsterdam, Frankfurt am Main, Munich and Brussels) with large airports (Heathrow, Charles de Gaulle, Schiphol, Frankfurt am Main, Munich and Zaventem).
For LE, and CTMs in general, the quality of the input data could determine to a large extent how well modelled atmospheric pollutant concentrations reflect reality. Arguably the most important of these inputs is the emission dataset, that describes how quantities of pollutants emissions are temporally and spatially represented in the model. An initial exploration into the most suitable emission dataset led to the conclusion that the GrETA (Gridding Emission Tool for ArcGIS) and ER (Emission Registration) datasets were most equipped for 1x1 km resolution simulations so should be used whenever available (i.e., Amsterdam, Frankfurt am Main and Munich). Alternatively, when this set is not available, a CAMS-REG v5.1 1x1 km dataset could be used (London, Paris and Brussels).
The results from the simulations with the selected emission datasets show:
- An average contribution from aviation to the annual NO2 concentration in the respective city centres of 2.5%.
- For SO2, PM2.5 , and PM10 the relative contributions are respectively 1.8%, 0.5% and 0.3%.
- At the airports locations, the average relative contributions from aviation to the concentration of NO2, SO2, PM2.5 , and PM10 over the six airport that were simulated are respectively 38%, 45%, 6.0% and 4.5%.
Next to NO2, also SO2 receives a high relative contribution from aviation, but in absolute values the total SO2 concentrations attributed to aviation are much lower (between 6.1 μg/m3 and 2.0 μg/m3) and of less concern than the respective NO2 concentrations (between 25 μg/m3 and 30 μg/m3). For relatively long-lived PM, the relative contribution from aviation is lower. Hence throughout this report NO2 will get most attention.
Most cities have a large number of inhabitants that live in the area between the airport and the city centre and hence are exposed to NO2 concentrations with a contribution from aviation that lies between the average city centre contribution of 2.5% and the average contribution at the airport of 40%. London is the largest city with nearly 10 million inhabitants in the city centre and it was found that:
- At Heathrow (LHR) airport the NO2 concentrations are significantly elevated with a contribution of 55% (17 μg/m3) from aviation.
- In the city centre of London the contribution is diminished to 1.6% (0.44 μg/m3).
- In addition, the densely populated regions between city centre and airport exposures will vary in this range.
- It was also found that the relative contribution of aviation drops off at a rate of 50% per 2.6 km distance from the airport.
Paris is the second largest city with 7.8 million inhabitants in the urban area, followed by Munich with 2.5 million residents. These cities as well as the smaller cities (Frankfurt am Main (2.3 million), Amsterdam (1.5 million) and Brussels (1.3 million)) show a similar trend of decreasing concentrations from airport to city centre in a comparable range.