Modelling elemental carbon at regional, urban and traffic locations in The Netherlands

The annual concentration of elemental carbon (EC) has been derived for The Netherlands in 2011. National emissions contribute 55% to the average EC concentration in the Netherlands. About 65% of the national contribution comes from emissions from road traffic and about 35% from other mobile sources (15%), households (14%), shipping (4%) and other combustion sources (2%). Conversion factors were established to compare different methods of EC measurement such as Black Smoke, Black Carbon and thermal analysis. The measured regional and urban background concentrations and variability were 0.5 ± 0.1 and 0.9 ± 0.1 μg EC per m3, respectively. The ratios between modelled and measured regional and urban background concentrations were 1.6 ± 0.5 and 1.8 ± 0.4, respectively. The modelled values are likely to be overestimated. The modelled and measured traffic contributions to EC concentrations near motorways and in street canyons were in the range 1.1–1.3 μg m−3 with total EC concentrations of 2.0 and 2.2 μg m−3, respectively. Our study showed that EC concentrations near intense traffic are increased with a factor 2–4 as compared to the urban and regional background, respectively. Consequently there is a similar variation in exposure and potential health effects in the population. More measurements of EC are required to improve modelling of EC concentrations in particular at urban background and near traffic locations.