Method of passive sampling for measurement of nitrogen dioxide in atmospheric air
V.A. Poddubnyi, N.A. Yushketova
Institute of Industrial Ecology Ural branch of RAS, 20a, str. Sof'i Kovalevskoj, GSP-594, 620219, Ekaterinburg
Keywords: nitrogen dioxide, air pollution monitoring, low cost monitoring methods, passive sampling, physico-chemical model
Abstract
Passive sampling is a simple low-cost method for assessment of concentrations of gases in air. In comparison with standard methods, the precision of the results of passive sampling measurements is more influenced by meteorological and methodological factors. Results of theoretical and experimental studies of a number of factors, which influence the precision of the results of passive sampling measurements of ambient NO2 are presented. Comparison of passive sampling method and reference methods (sorption tubes, chemiluminescent gas analyzer) under moderate continental climate conditions demonstrated systematical statistically significant underestimation of concentrations, measured by passive samplers method. It was shown that the difference observed is accounted for the drawbacks of the model commonly used for treatment of passive sampling data; the model does not take into account particularities of interaction between NO2 and sorbent solution that are related to the influence of relative humidity. A new NO2 passive sampling model based on available data on interaction between NO2 and a sorbent solution was developed. Application of the model allowed us to improve agreement between NO2 concentrations calculated from passive sampling data and those measured by reference methods, to eliminate systematical and statistically significant difference between the datasets.
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