Vehicle Non-Exhaust Pm and Pn Emissions: A Comprehensive Assessment in European Countries

Abstract

Vehicle non-exhaust emissions contribute to adverse environmental and health consequences. The EU has recently put forward the Euro 7 standard proposal that for the first time includes vehicle non-exhaust emissions under control with limit requirements. However, in contrast to widely-studied exhaust emissions, there remains a paucity of evidence on vehicle non-exhaust emissions from various sources and in different particle sizes, and on how such emissions will change over time. This study is the first to evaluate vehicle non-exhaust Particulate Matter (PM) and Particle Number (PN) emissions in these aspects, by focusing on four European countries, namely, Germany, Spain, France, and the UK. We investigate 2016-2018 non-exhaust PM (total suspended particle, PM10, PM2.5, PM1 and PM0.1) and PN (PN10, PN2.5, PN1 and PN0.1) emissions from various vehicle categories, and on these bases, predict the emissions in 2050. The largest proportion of exhaust PM or PN emissions in the four countries are from passenger cars (PCs), followed by light-duty vehicles (LDVs), heavy-duty vehicles (HDVs), and buses. While the emission mass of ultra-fine particles (PM0.1) in the total non-exhaust PM emissions is almost negligible, the PN0.1 emissions from tyre and brake wear are incredibly high, about 155,500 times higher than the PN10 emissions. In the foreseeable 2050, the total PN0.1 emissions from the four vehicle types will increase by an average of 16.5%, 30.2%, -2.4%, and 39.6%, respectively, compared to 2018 in the four countries. In view of the rapid growth rate of non-exhaust PN emissions, mainly from LDVs and buses, and potential air pollution effects, our research findings call for an urgent need to incorporate ultra-fine PN limits in EU emission standards.

Keywords: Vehicle non-exhaust emissions, Road traffic, particulate matter, Particle Number, Europe