Measurement of nitrogen dioxide diffusive sampling rates for Palmes diffusion tubes using a controlled atmosphere test facility (CATFAC)

Distributions of air pollutants associated with oil and natural gas development measured in the Upper Green River Basin of Wyoming

“…Measurement surveys of the spatial distributions of species of interest were conducted using passive diffusive samplers. This technique was first developed in 1973 (Palmes and Gunnison, 1973), and has been subsequently refined and is now well established (e.g., Varns et al, 2001;Carmichael et al, 2003;Muckerjee et al, 2004;Bruno et al, 2005;Gerboles et al, 2006;Pérez Ballesta et al, 2008;Cocheo et al, 2008;Buczynska et al, 2009;Martin et al, 2014). The method, which relies on the diffusion of a pollutant species to a collection medium, typically an adsorbent material, allows a wide range of trace gas concentrations to be measured in both indoor and outdoor environments (Zabiegala et al, 2010).…”

Validation of ammonia diffusive and pumped samplers in a controlled atmosphere test facility using traceable Primary Standard Gas Mixtures

“…A modified controlled atmosphere test facility (CATFAC), consisting of a wind tunnel with an internal volume of approximately 1000 L (Martin et al, 2003;Martin et al, 2014) was employed to carry out validation tests on simultaneously exposed ammonia diffusive and pumped samplers. Here a series of test atmospheres at relevant NH 3 ambient concentrations were generated at nominally: 3, 7, 10, 15, 17, 20 and 25 µg m -3 , (where 1 µg m -3 NH 3 is equivalent to an amount fraction of 1.41 nmol mol -1 at a reference temperature of 20 °C, or 1.41 ppb (parts per billion)).…”

“…The sampling mechanism for the passive devices employed in this work is described by Fick's first law of diffusion, which has been discussed extensively in a number of publications (Martin et al, 2014). Very briefly, the ambient concentration of ammonia, [NH 3 ], either in a test chamber or in the field, may be determined from Equation 1:…”

Efficacy of passive sampler collection for atmospheric NO2 isotopes under simulated environmental conditions

“…In addition, given that turbulence was undetectable in the chamber (i.e., turbulence could shorten the total diffusion path), this indicates that higher effective sampling rates from turbulent conditions were not the cause of >100% collection efficiency . Together, this suggests that overestimated collection efficiencies are probably due to uncertainty in the theoretical concentration calculation, rather than previously documented environmental or contamination factors in studies using open NO 2(g) diffusion tubes …”

“…[55] Together, this suggests that overestimated collection efficiencies are probably due to uncertainty in the theoretical concentration calculation, rather than previously documented environmental or contamination factors in studies using open NO 2(g) diffusion tubes. [55][56][57][58] The δ 15 N-NO 2 values determined for the reference gas tank ranged from -39.5 to -40.0 ‰ (n = 3), with an average of -39.8 ± 0.2 ‰ (Fig. 2).…”