Abstract
Three passive samplers are now commercially available for NO2. This field validation, conducted in an underground mine, attempted to address both the precision and accuracy of the three now commercially available. The probable sources of NO2 were identified as diesel engines and blasting operations. Comparative sampling was conducted with the passive samplers versus the standard “baseline” impingement method. The three NO2 samplers were as follows: 1) PRO-TEK® (DuPont); 2) Palmes® (MDA); 3) VaporGard® (MSA). Three sets of data consisting of impingers and passive sampler results were taken on top of a moving diesel vehicle over a three-day period. An expanded metal screen was welded in a “free standing” plane above the vehicle to serve as a sampling platform. The evaluation of concentration data suggested that correlations of accuracy and precision versus the impinger method were best for the Palmes and VaporGard samplers. The PRO-TEK sampler does not seem to produce accurate data, but it is somewhat precise. Factors of sensitivity, accuracy, precision, cost, ease of analysis, and stability must be weighed.