Prevent smog episodes in Europe: Air quality impact of engine-emitted volatile, semi volatile and secondary particles

The impact of transport emissions on air quality and health is relatively well known as far as direct pollutants emission are concerned, i.e. particulate, NOx, hydrocarbons etc. However, some of the emissions from engines and combustion processes in general are also leading to further formation of health impacting compounds due to atmospheric aerosol chemistry, and the specific impact of these compounds is less understood (except for ozone, whose chemistry has been widely studied for other reasons). Also, in fields where regulation limits particles emissions (cars, trucks, aircraft, non-road mobile machinery) current engine particles emissions count only assesses the number of solid particles, disregarding the so-called volatile and semi-volatile particles, thus underestimating the impact on air quality and health.

Proposals should assess in detail engines emissions in Real Driving Emissions (RDE)-compliant testing conditions (based on currently used fuels) leading to volatile and semi-volatile and secondary particulate, taking into account the wide available literature and results from projects issuing from topics LC-MG-1-1-2018 and GV-02-2016, prioritise them according to available information and assess their health impact with relevant modelling and in vitro and in vivo testing.

After assessing the risks associated to each emission, proposals should define a robust and transparent measurement and modelling system in order to determine an equivalent total particles emissions index for each engine encompassing all these emissions, to complement the direct solid particles emissions count currently in use to better quantify the total externalities of combustion engines in all transport fields and related fuels.

In line with the Union’s strategy for international cooperation in research and innovation, international cooperation is encouraged.