Size-segregated analysis of PM10 at two sites, urban and rural, in Münster (Germany) using five-stage Berner type impactors

Airborne particulate matter was collected at two sites, using five-stage Berner type impactors. Their different exposures to the emission sources in Münster, Germany, was examined during a campaign in January 2006. The scope of this project was to identify the sources of particulate material with the help of size- and time-resolved chemical characterisation of the particle components. The major ions such as Ca2+, Cl−, Mg2+, Na+, NH4+, NO3−, SO42−, and carbon were analysed. The mean mass concentration of particulate matter was higher at the urban roadside than at the regional background (rural site). The main difference exists for the carbon concentration, which is in the city 1.8 times higher than in the surrounding area. The ion concentrations showed identical concentration levels at both sites, with slightly higher concentrations at the roadside, due to Na+, Cl−, and Ca2+. The mass concentrations of particulate matter vary both between the sites and with time. At daytime, clearly higher amounts of particulate matter can be found at the roadside. Slightly enhanced concentrations of the secondary ions NH4+ and NO3− were found at night, but the difference is smaller than the daily increase of the particle mass due to carbon.