• PM 2.5 concentration reduced by 21% with spatial variations of 6-34% compared to the average of the same days in 2018-2019 • CO and NO 2 concentrations reduced by 49% and 35%, respectively • O 3 concentrations increased by 15% compared to the preceding 17 days before the lockdown • Concentrations of benzene and toluene were 2-3 times higher than in the same seasons of 2015-2019.

Air pollution is one of the primary sources of risk to human health in the world. In this study, seasonal and spatial variations of multiple volatile organic compounds (VOCs) were measured at six sampling sites in Almaty, Kazakhstan. The seasonal and spatial variations of 19 VOCs were evaluated in 2020, including the periods before and after COVID-19 lockdown. The concentrations of 9 out of 19 VOCs had been changed significantly (p < 0.01) during 2020. The maximum concentrations of total VOCs (TVOCs) were observed on 15, 17, and 19 January and ranged from 233 to 420 µg m−3. The spatial distribution of TVOCs concentrations in the air during sampling seasons correlated with the elevation and increased from southern to northern part of Almaty, where Combined Heat and Power Plants are located. The sources of air pollution by VOCs were studied by correlations analysis and BTEX ratios. The ranges of toluene to benzene ratio and benzene, toluene, and ethylbenzene demonstrated two primary sources of BTEX in 2020: traffic emissions and biomass/biofuel/coal burning. Most of m-, p-xylenes to ethylbenzene ratios in this study were lower than 3 in all sampling periods, evidencing the presence of aged air masses at studied sampling sites from remote sources.

The objective of this study was to investigate the impact of COVID-19 lockdown on different air pollutants in eight cities of Kazakhstan by employing the data from the National Air Quality Monitoring Network. We selected eight cities located in different regions of the country with varied climatic and geographic conditions and emissions sources, providing good conditions for studying the differences in responses of air quality to COVID-19. Due to severe winters, the heating season in Kazakhstan has a significant impact on air quality; therefore, annual winter/spring changes in air quality were also compared. The positive effect of the COVID-19 lockdown (spring 2020) on NO 2 and CO levels was observed in 5 and 3 cities, respectively (out of 8). Total Suspended Particles and SO 2 exhibited a more complicated response to COVID-19 lockdown: cities had a varying effect. No impact of lockdown measures was observed in industrial cities (Ust-Kamenegorsk and Karagandy), but seasonal changes were significant. In addition, despite some improvements during the lockdown period, the air quality in seven out of eight cities was still below the safety levels. The atmospheric quality in urban areas of Kazakhstan has not improved significantly due to the lockdown measures. This study underscores the importance of imposing stricter air quality emission control over industrial enterprises and coal-fired power plants. Supplementary Information The online version contains supplementary material available at 10.1007/s40710-022-00603-w.

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