Elemental carbon as an indicator to monitor the effectiveness of traffic related measures on local air quality

Even when European standards on air quality are met, health effects occur near busy roads because of the increased exposure to tailpipe emissions. For a proper assessment of these effects, an additional indicator is available: elemental carbon (EC). This is a sensitive indicator for particulate matter from combustion emissions by road traffic. Currently, the concentrations of EC along busy roads are still significantly increased relative to the background, in contrast to PM10 and PM2.5. Therefore, the effectiveness of traffic measures on local air quality and associated health effects can be better assessed with EC than with PM mass. This paper discusses the relevance of EC as an indicator in the assessment of air quality and health. This is illustrated with two pilot studies in the Dutch cities of Arnhem and Helmond where traffic measures were evaluated with EC measurements. Also model calculations of the effect of 80 km/h speed limit zones on Dutch motorways on the health risks of local residents are presented. It is concluded that the assessment of EC through monitoring and/or modelling is a powerful policy instrument to analyse the impact of local traffic measures on air quality and health. Typically, people living close to busy road transport may live 1 to 6 months longer when measures like enhancing traffic flow, speed limiting and environmental zoning are implemented