PRECISION OF OUTDOOR BENZENE CONCENTRATION MEASUREMENT, FOR SHORT SAMPLING TIME, BY PASSIVE AND ACTIVE PERSONAL SAMPLERS

摘要

The precision of two analytical methods for the measurement of benzene concentrations in outdoor atmosphere, collected for short sampling time (six hours), by Perkin Elmer (P.E.) passive tubes and by active personal samplers, was tested in the field. Multiple simultaneous samplings, for each sampling method, were carried out at six different days along a traffic street of Genoa, Italy. Data proved that the mean precision of each method (evaluated as percent differences of each sample, respecting the mean value of simultaneous measurements) was 2.7 ± 1.6, using active sampling, and 4.6 ± 3.2 with the passive method. The precision of passive sampling mainly depends on blank samples variability (0.4 ± 0.2 ng of benzene). Benzene concentrations measured simultaneously by the two sampling methods were linearly correlated (r = 0.905; 0.01 < p < 0.05) with the angular coefficient not different from 1. These results confirmed the possibility to use P.E. passive samplers to measure outdoor benzene also for short sampling time, reducing at minimum the contamination of sampling tubes during their conditioning and storage.