Theoretical basics of the air quality monitoring for urban areas: Thermodynamical characteristics of atmospheric pollution

Urban air pollution is caused by a combination of different sources. Their contribution to the air quality must be evaluated based on quite reliable data collected by the optimal net of the monitoring points. Under these conditions, the data on special marker compounds are to be obtained. But the selection of marker compounds and optimal places for control points requires to justify the distribution pathways of the pollutants. Thus, it is necessary to study the mechanisms of the accumulation of marker compounds in the environmental media as a result of their sedimentation from the atmosphere. As marker compounds we consider polycyclic aromatic hydrocarbons (PAHs) - relative stable in the environment compounds, owning the justified toxic properties and “connected” with specific anthropogenic or natural processes. Thus, indicator ratios of these compounds can be evidences of origin of the pollution. The presence of several PAHs is strongly connected with a specific source. To understand the mechanisms of the pollution, we processed a wide set of initial data (over 140 samples) reflecting the pollution of different environmental media with PAHs. Studying the thermodynamic characteristics of the pollution (entropy, enthalpy, Gibbs energy of a set of PAHs in each sample) we identify the leading factors for the formation of a several level of pollutions. For the processing of data collected, the classic multivariate statistical procedures have been applied - cluster analyses as well as correlation analyses. The result of our studies is a preliminary classification of the pollution conditions in different environmental media and under various level of anthropogenic pressure. The dendrogramms obtained as a result of cluster analyses allow to identify visible differences in the accumulation mechanisms for the PAH pollution in plant samples, in snow cover samples and soils contacting with the polluted air. These results allow us to distribute accents in the environmental monitoring of air pollution and to shift from the only air pollution measurements to the complex atmospheric pollution monitoring, including the study of a set of consequences of the atmospheric pollution. © 2019 International Multidisciplinary Scientific Geoconference. All rights reserved.