Ecological Systems and Devices Annotation << Back A Physic-Chemical Model of Nitrogen Dioxide Sorption Processes in Passive Sampling Poddubny V.A. Yushketova N.A. In NO2 passive sampling measurements aqueous triethanolamine (TEA) solutions are widely used as absorbing media. Nitrogen dioxide sampled is accumulated as nitrite-ions. The results of methodological passive sampling measurements of NO2 showed that application of the model commonly used to describe passive sampling processes might lead to substantial random as well as systematical uncertainties. Presented in the article is a new physico-chemical model of the process of NO2 passive sampling using TEA solutions which is based on available experimental data on interaction between NO2 and solutions of TEA. The key principles underlying the model are: 1) when absorbed by trapping solution, NO2 forms nitrite ion only on the condition that TEA is hydrated; 2) coefficient of conversion of NO2 to NO–2 is equal to one when reacting with hydrated TEA; 3) the fraction of hydrated TEA molecules depends on air humidity at the moment of measurement. Validation of the model was made using the data of the field measurements carried out in the Middle Urals in 2007–2009. It was shown that the new model eliminates statistical significance between the NO2 concentrations obtained from passive sampling measurements and those measured by reference methods and improves the agreement between these datasets. Keywords: nitrogen dioxide; air pollution monitoring; passive sampling; diffusion tube; triethanolamine; physic-chemical model. Contacts: E-mail: yushketova@gmail.com Pp. 21-32.