Sampling of nitrogen dioxide in a coal dust atmosphere

The purpose of the study was to determine if coal dust would affect the collection of nitrogen dioxide by an active and two passive personal samplers (TEA tube, Palmes' tube, and DuPont Pro-Tek© badge, respectively). The study was designed to expose an equal number of the three samplers to a mixture of nitrogen dioxide (5 ppm) 3 and coal dust (2 mg/m total dust). Results from these experiments were compared to the results of sampling done under the same conditions without the coal dust present. The sampling was done during eight two-hour sampling periods, four in the presence of coal dust and four in the absence of coal dust, in an enclosed chamber in which humidity, temperature, air velocity, pressure, coal dust concentration, and nitrogen dioxide concentration could be monitored. No statistical differences were seen in the collection of nitrogen dioxide in the presence of coal dust with the three samplers at the stated conditions. The sampling results from the Palmes' tube suggested an increased collection of nitrogen dioxide in the coal dust atmosphere; however, results may have been influenced by the sampling location. The sampling results from the DuPont Pro-Tek© badge were highly variable, and individual results from this sampler are considered questionable. The sample results from the TEA tube were accurate but not precise and again were thought to possibly be affected by the sampling location. It can be concluded that, due to its accuracy, preciseness, and low cost, the Palmes' tube was the most effective device tested for personal sampling of nitrogen dioxide under the experimental conditions.