MEASUREMENTS OF NO2 CONCENTRATIONS IN THE AIR USING PASSIVE PALMES SAMPLERS .1. LABORATORY STUDIES AND QUALITY DESIGN

NO2 concentrations were measured in the air of a test chamber using pa ssive samplers according to Palmes. The Palmes tubes were exposed over different sampling intervals and at different air temperature, air hu midity and air velocity. The results were compared with NO2 concentrat ions determined by automatic monitors. Good agreement was found betwee n the results of the Palmes tube and those of the monitor measurements . The passive samplers can be used for exposure intervals between two and 13 days. Higher air velocity and, sometimes, also high air tempera ture together with high air humidity, result in slightly higher passiv e sampler concentrations as compared to the automatic monitor. Low air temperatures (< 0 degrees C) resulted in lower passive sampler concen trations.