Particulate matter < 10 μm (PM10) and total suspended particulates (TSP) in urban, rural and alpine air in Switzerland

Ambient concentrations of particulate matter of less than 10 μm aerodynamic diameter were measured in Switzerland for a 1 yr period in 1993 at a dozen urban, rural and alpine sites. PM10 concentrations ranged between 10 μg m−3 (alpine) and 33 μg m−3 (urban). Highest concentrations were found at Lugano, in the south of the Alps, and in urban sites of the Swiss Plateau (350–670 m.s.l.). Rural levels were one-third lower than the urban levels and relatively homogeneously distributed. Alpine sites showed considerably lower levels. The ratios between PM10 and TSP were found to be between 0.6 and 0.75, and the highest ratios were found in the most polluted urban sites. Seasonal variation of particulate pollution showed peak levels during winter and autumn, mainly during cold temperature-inversions. Statistical analyses have shown a good correlation between PM10 and NO 2 and S02, and TSP in urban areas.