Modern trends in changes in the content of climatically and ecologically important impurities in the atmosphere of the Volga Federal District.

The problem of atmospheric air quality is one of the main environmental challenges of our time, being in the center of attention of specialists and international organizations. This paper presents a study of the spatio-temporal distribution of impurities in the atmosphere in the Volga Federal District (VFD) based on EAC4 (CAMS) reanalysis data for the period 2003-2022. 

Based on information published in annual environmental reviews by territorial divisions of Roshydromet in the Volga Federal District, the author selected the following pollutants for study that make a significant contribution to air pollution: formaldehyde (CH₂O); sulfur dioxide (SO₂); nitrogen dioxide (NO₂). WMO classifies these pollutant ingredients as important climate variables, including those that contribute to the formation of aerosols and ozone.

The paper analyzes the seasonal variation of the average fields of content of selected air pollutant ingredients; conducts a trend analysis; identifies significant correlations between pollutant fields and key meteorological factors based on ERA5 reanalysis data.

The following conclusions were made during the study.

The distribution of average values ​​of the total CH₂O reserve in the atmospheric column of the VFD has a pronounced seasonal variability with maximums in the summer months and minimums in the winter. Inverse seasonal dependence was revealed in the distributions of the SO₂ and NO₂ content. The standard deviation of the average content of impurities has a similar seasonal dependence.

For CH₂O and NO₂, the tendency to accumulation prevails throughout most of the year. For SO₂, the tendency is negative everywhere in the winter period, and positive only in places in the summer.

The nature of the correlation links with the temperature of the surface air layer for the average content of the studied impurities in the atmospheric column is different. Positive links are noted with CH₂O (throughout the year) and SO₂ (from May to September); negative links – with SO₂ (in January-February) and NO₂ (throughout most of the year). In the field of the u-component of wind speed, there are close negative links with SO₂ throughout the year. In the field of the v-component, there are close positive links for SO₂ and NO₂ (April – October). In the field of large-scale precipitation, there are close positive links with CH₂O in the winter months; with NO₂ – in individual winter and spring months. Significant negative links were revealed with CH₂O in July, with NO₂ in July-September, with SO₂ in individual months throughout the year (the closest ones – in February and August).