CHARACTERIZATION OF PARTICULATE AIR-POLLUTION IN URBAN AND NONURBAN AREAS IN THE NETHERLANDS

During the winters of 1992/1993, 1993/1994 and 1994/1995 a monitoring study was performed in three urban and three non-urban areas in the Ne therlands. PM10, black smoke (BS), sulfate, nitrate, ammonium (non-org anic secondary aerosols, ''NOSA'') and aerosol acidity were measured o n a daily basis in both the urban and non-urban areas. During the thir d winter, PM2.5 was measured as well. The elemental composition of PM1 0 was analyzed for one-third of the filters collected during the winte r of 1993/1994 with inductively coupled plasma (ICP). PM10 and BS conc entrations were on average 13% and 19% higher in the urban areas than in the non-urban areas. NOSA concentrations were on average 8% lower i n the urban areas. PM2.5 concentrations were similar in the urban and non-urban area. Higher elemental concentrations in PM10 were found in the urban area for all elements except Si. The contrast between elemen tal concentrations in PM10 was for most elements larger than for PM10 mass concentration. The small contrast in particle concentrations betw een urban and non-urban areas in the Netherlands is probably a result of the small size of the country, the high population density, the lac k of small-scale geographical and meteorological differences, and the importance of long-range transport of air pollutants. Both the absolut e concentrations of PM10, BS and NOSA and the urban-non-urban differen ces depended strongly on wind direction. Easterly winds resulting in a n influx of air masses from Central and Eastern Europe were associated with high concentrations and minimal urban-non-urban differences. Win ds from the sea resulted in low concentrations but larger relative dif ferences between urban and non-urban areas. (C) 1998 Elsevier Science Ltd. All rights reserved.