Abstract
Road transport, Emission reduction, air quality improvement, Nitrogen oxides, Particulate matter Progress in vehicle technologies and electronics as well as in fuel quality significantly reduced the emission of CO, HC, NOx, particles and SO2 in Europe. Improvements both from passenger cars and duty vehicles lowered the exhaust emissions for new registered vehicles so much that the penetration of these new vehicles in the vehicle fleet results in a significant decrease in all exhaust emissions in Europe. As a consequence air quality in European cities is improving for those components. Only adverse meteorological conditions lead to exceedances of the stringent air quality standards in a few cases. Air quality measurements show that for carbon monoxide concentrations in cities are already far below the air quality standards, for NO2 former standards have been met, the standards valid in 2010 will be met in most cases. For the secondary formed component ozone the standard of 120 µg/m3 is very close to background levels in summer. The standard will be met in cities but exceeded in rural regions due to the contribution of biogenic terpene, isoprene and ethylene emissions. Maximum O3-values even outside cities are decreasing, due to the reduction of photochemical precursors HC and NOx from all sources. Total suspended particulates are not a problem anymore, PM10 could remain a problem in areas with a higher contribution of stationary sources, elemental carbon from road transport is decreasing far enough to reach the targets set for 2010. SO2 - mainly from stationary sources has lost the leading role as pollutant. The small contribution of road transport in the past is reduced further because sulfur is banned from future fuels. Regarding particulate matter from road transport not only the mass but also the number and surface of PM-emissions is decreasing.