nPETS - Nanoparticle Emissions from Transport Sector

The nPETS project focuses on sub-100 nm particle emissions from road and rail vehicles, and aircraft. These particles, commonly referred to as ultrafine particles, are known to be efficient infiltrators to human respiratory system. In addition to emissions from internal combustion engines, any part that wears during operation of a vehicle can act a source of such particles.

Particulate matter (PM) emissions from vehicles and aircraft can form a significant fraction of atmospheric aerosol burden in locations where traffic density is high, such as near arterial roads and airports. In addition to these hotspots of PM emissions from vehicles, the significance of ultrafine particles is more pronounced in nearly enclosed spaces, namely road tunnels and underground railway stations.

Non-exhaust PM emissions from motor vehicles, propelled by either internal combustion engines or electric motors, inevitably form a fraction of total emission budget of vehicle operation. With ongoing electrification of passenger vehicles and upcoming Euro7 regulations on combustion engine emissions, it can be expected that the fraction of non-exhaust PM emissions will dominate within a decade or two in the developed markets.

Passenger rail transport is mostly electrified in urban areas of the developed countries, meaning that the non-exhaust PM emissions from this source dominate. These emissions originate from rail-to-wheel contact, brake pads, and the third rail contact, for instance. In air traffic, PM emissions additional to ones from jet fuel originate from wheels during take-off and landing, brake pads and activities related to runway maintenance.

Knowledge gaps still exist on several properties of such particle types, including not only quantification of their sources but also their toxicity. In addition to the properties of primary particles, the secondary aerosol production potential from the sources on the scope remains largely an open question.

The nPETS project aims to:

1. identify and quantify ultrafine particle emissions from different modes of transportation,
2. characterise the abovementioned emissions (including secondary aerosol potential),
3. explore their toxicological effects on human health, and
4. quantify the effect of policy changes related to air quality

This project is funded by the European Union as a part of Horizon 2020 research and innovation funding programme, grant no. 954377.

KTH Royal Institute of Technology, Sweden