Chemical composition of PM10 in Switzerland: An analysis for 2008/2009 and changes since 1998/1999

In this study, the chemical composition of PM10 at various sites in Switzerland during a one year period in 2008/2009 and changes since the time of a similar characterisation campaign in 1998/1999 are investigated. The concentrations of main components of PM10 were found to be similar at different site types north of the Alps (i.e. urban background, suburban and rural sites). Secondary inorganic PM10 components (nitrate, sulphate and ammonium) constituted the largest PM10 mass fraction, followed by carbonaceous matter (OM and EC), while the abundance of mineral dust and trace elements was small (both <10%). At a rural site south of the Alps the concentrations of secondary inorganic components were much lower and the concentrations of OM and EC clearly higher than north of the Alps. Enhanced concentrations of EC, trace elements and to a lesser extent of OM and mineral dust were found at an urban roadside site. At this site, typical traffic related trace elements like Cu, Fe, Mo, Sb and Ba were highly enriched.This paper indicates clear positive effects of emission reduction strategies for PM10 and precursors implemented during the past ten and more years. The concentrations of sulphate and EC declined during the considered time period, EC reductions were especially strong at the urban roadside site (−2.4 μg m−3). In contrast, the concentration of nitrate slightly increased at all of the considered sites (0.2–0.5 μg m−3). Large reductions in the concentrations of many trace elements in PM10 during the past ten years are evident. As an example, the observed relative decrease of Pb is about −80%, which is a success of the ban of leaded gasoline in Switzerland and in the EU.

► Chemical composition of PM10 at different site types in Switzerland is investigated.
► The results are compared with data from ten years before. 
►  Sulphate, elemental carbon and various trace elements declined during past ten years.
► In contrast, nitrate concentrations slightly increased.
► The observed changes allow an assessment of implemented emission control measures.