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Blue Sky Recovery: How zero-emission vehicles and reduced car use will allow cities to keep lockdown low levels of air pollution

18-03-2021

The air quality changes brought about by the unprecedented lockdown of European cities during the early stages of the Covid-19 pandemic can be replicated through changes to mobility policies, research by AQC has shown. AQC has published its analysis, commissioned by the Brussels based NGO Transport and Environment, of policy scenarios to show how the air quality benefits seen during the most stringent phase of Covid-19 lockdowns could be achieved through changes to mobility policies.

The air quality changes brought about by the unprecedented lockdown of European cities during the Covid-19 pandemic can be replicated through changes to mobility policies, research released today by AQC has shown. The report can be found here.

The response to Covid-19 across Europe has resulted, as a side effect, in a significant improvement in urban air quality. European sustainable transport NGO, T&E, commissioned Air Quality Consultants to quantify the air quality improvement across several European cities and see whether the same improvement could be achieved by changing the vehicle fleet and modal shifts.

AQC used a de-weathering model (boosted regression tree) to quantify the “real” improvements between the most severe phase of lockdown in early 2020 and previous years for six cities – Berlin, Brussels, Budapest, London, Madrid and Paris. This revealed reductions in mean NO2 of between 3.2µg/m3 (Budapest) and 27.3 µg/m3 (Central London), with Paris showing the highest city-average improvement, at 20.6 µg/m3.

The report goes on to estimate the traffic contribution, based on a combination of air quality monitoring data and traffic data derived from emission inventories, and then to test how a series of scenarios based on conversion of the vehicle fleet to zero exhaust emission alternatives, plus a combination of increased walking, cycling and home working, could produce the same effects.

Two types of scenarios were investigated: Two that rely on a switch to zero exhaust vehicles (ZEV) only, and three that look at a combination of ZEVs with modal shift and demand reduction. The findings show that, other than in Madrid and Paris, both types of scenarios can achieve reductions equivalent to lockdown levels: focusing on cars only, between 42% (Budapest) and 92% (London) of all car-km need to be shifted to ZEVs. When using a combination of ZEVs with more walking, cycling, public transport and reduced car use, the necessary shift to zero-emission cars can be achieved more rapidly, with a need to shift between 6% (Budapest) and 74% (London) of all car-km need to zero exhaust emissions.

In two of the cities (Madrid and Paris), which have seen particularly strong reductions of traffic-related NOx emissions during lockdowns, only a mix of both strong modal shift and a switch to ZEVs more widely (including also vans and trucks) can deliver the targeted reductions. In Paris 67% of all vehicle-km need to be switched to ZEVs. In Madrid, 10% of all km travelled by light and heavy-goods vehicles as well as 94% of car-km need to convert to ZEV.

For further information, contact TimWilliamson@aqconsultants.co.uk

T&E’s own report on the project can be found here.



© Air Quality Consultants 2021