Remote Spectrometric Measurements of Atmospheric Nitrogen Dioxide near Urban Thermal Power Plants

Abstract

The operation of thermal power plants (TPP) is accompanied by the emission of various pollutants into the atmosphere, including nitrogen oxides. This paper presents the results of spectrometric measurements of the atmospheric NO₂ content carried out on circular routes around large urban TPPs of St. Petersburg. The spatial variability of tropospheric NO₂ content in the vicinity of a TPP is determined based on experimental data received by the DOAS (Differential Optical Absorption Spectroscopy) method and shows high values in the downwind side of stacks. The spatial distributions derived from the mobile DOAS measurements are confirmed by the results of numerical calculations of the NO₂ content field with the HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectories) model taking into account a priori information on the volume of NO_x emissions from main urban TPPs. Approximate estimates of NO_x emissions from two the largest TPPs in St. Petersburg from calculations of the total flux of NO₂ molecules through a loop-route DOAS measurements amount to ∼2–3 kt per year. These experimental data are important for determining the contribution of thermal power plants to anthropogenic atmospheric pollution.