Validation of a diffusive sampler for NO2

A diffusive sampler for NO2, Willems badge, was validated in laboratory exp eriments and held tests. The collecting reagent for NO2 in the sampler is t riethanolamine, and the analysis is based on a modified colorimetric method , the Saltzman method. The analysis was performed by a flow injection analy sis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 ml min(-1). There was no effect of NO2 concentration or relative humi dity on sampling rate, and the influence of sampling time was found to be s mall. The detection limit was 4 mu g m(-3) for a 24 h sample. The capacity is high enough to allow sampling of 150 mu g m(-3) for 7 days, which is twi ce the recommended Swedish short-term (24 h) guideline value as a 98-percen tile over 6 months. In held tests, the sampler performed well, even at wind speeds higher than 2 m s(-1), and at low temperatures. The overall uncerta inty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2-8 h in working environments.