Recent research for the EPHA has indicated that the average European citizen faces a welfare loss of over € 1,250 per year due to poor air quality. At present, the transport sector contributes roughly 40 to 50% to overall NOx emissions and 10 to 15% to PM emissions. On average, the current share of transport in ambient NO2 concentrations is estimated at 50%, but there are major differences among regions and cities.
This study reviews the impacts of transport-related policy measures in cities and how they affect air quality. We focus on five policy measures:
Based on a previous evaluation of social costs in 432 European cities in 2018, an estimate was made of the potential reduction of social costs due to the five selected measures in 2020.
The impact of the five selected measures on PM and NOx emission reductions is shown in Figure 1. It is clear that Congestion charging and Low-Emission Zones (LEZ) have the greatest potential to reduce transport PM and NOx emissions in cities. Based on evaluations of cities that have implemented these measures, a 10 to 20% reduction in emissions is attainable. There are major uncertainties, however, as the effectiveness of measures depends largely on the stringency with which they are enforced and the size of the zone
Parking policies can also be fairly effective, reducing PM and NOx emissions by somewhere between 5 and 10%. Car sharing and Cycling/walking policies are much less effective in terms of PM and NOx emission reduction, although particularly the latter has other benefits, such as increased health from active mobility and improved quality of city life if the space allocated to car traffic is simultaneously reduced.
The Initial costs of Congestion charging and LEZ are highest, although the costs of the former can largely be recovered from the fees collected. Cycling policies are costly if infrastructural changes are required, particularly in dense city areas where the available space is limited.
These potential ‘savings’ in social costs may encourage local/city governments to implement these measures. The findings in this study point to the fact that the relative contribution of an individual measure is rather limited: city governments aiming to reduce the social costs should consider more than just one measure.