Passive sampling of aromatic volatile organic compounds (VOC) in ambient air in Switzerland

Concentrations of benzene, toluene and m-xylene (BTX) were measured at urban, suburban, rural and alpine sites in Switzerland by means of passive sampling. Sampling time was two weeks and the sampling period was six months in succession. Concentrations ranged between 0.8 and 6 pg m(-3) for benzene, between 2.9 and 14 mu g m(-3) for toluene and between 0.9 and 7.4 mu g m(3) for m-xylene. The ratios between benzene toluene and m-xylene concentrations were on average 1:3:1.1. Passive samplers have been found to be a useful tool for the synchronical determination of VOC in different regions. Comparison with continuous monitors showed some systematic bias, however. Correlation of VOC with other air pollutants were strong with CO and NO.