Potential sources of reactive gases for the West of Moscow Oblast

Abstract

A.M. Obukhov Institute of Atmospheric Physics (OIAP) of Russian Academy of Sciences (RAS) performs regular measurements of the integral tropospheric content of such reactive gases as nitrogen dioxide (NO2) and formaldehyde (HCHO) by the MAX-DOAS method at the Zvenigorod Scientific Station (ZSS) since 2009. For each average hourly gas contents in the troposphere at ZSS in 2009-2017 the backward trajectories of the air particles were calculated using the trajectory model NOAA HYSPLIT_4 and the grid meteorological data NOAA NCEP GDAS0p5. Using the backward trajectories, the PSCF (potential source contribution function) method was used to calculate detailed (resolution 0.1°×0.1°) fields of probability of the transport to ZSS of air masses which are extremely polluted with formaldehyde and nitrogen dioxide from a potential source. Similarly, using the CWT (concentration weighted trajectory) method, detailed fields of the average contribution of the potential source to the tropospheric NO2 and HCHO contents at ZSS were reconstructed. The relative influence of the Moscow megacity and the industrialized region in the east of the Moscow Oblast on the contamination of the lower troposphere of the Western Moscow Oblast with nitrogen dioxide and formaldehyde is specified.