The origin of ambient particulate matter concentrations in the Netherlands

Particulate matter poses a significant threat to human health. To be able to develop effective mitigation strategies, the origin of particulate matter needs to be established. The regional air quality model LOTOS-EUROS, equipped with a newly developed labeling routine, was used to establish the origin of PM10 and PM2.5 in the Netherlands for 2007–2009 at the source sector level, distinguishing between national and foreign sources. The results suggest that 70–80% of modeled PM10 and 80–95% of PM2.5 in the Netherlands is of anthropogenic origin. About 1/3 of anthropogenic PM10 is of Dutch origin and 2/3 originates in foreign countries. Agriculture and transport are the Dutch sectors with the largest contribution to PM10 mass in the Netherlands, whereas the foreign contribution is more equally apportioned to road transport, other transport, industry, power generation and agriculture. For the PM2.5 fraction, a larger share is apportioned to foreign and anthropogenic origin than for PM10, but the same source sectors are dominant. The national contribution to PM levels is significantly higher in the densely populated Randstad area than for the country on average and areas close to the borders. In general, the Dutch contribution to the concentration of primary aerosol is larger than for secondary species. The sectoral origin varies per component and is location and time dependent. During peak episodes, natural sources are less important than under normal conditions, whereas especially road transport and agriculture become more important.