ABSTRACT
Central Asian cities are one of the hotspots for air pollution worldwide. There are limited studies and knowledge regarding air quality variation in this region. This study investigated PM2.5 temporal variations and the influence of meteorological parameters on PM2.5 concentrations for six major cities in Central Asia: Almaty and Astana (Kazakhstan), Ashgabat (Turkmenistan), Bishkek (Kyrgyzstan), Dushanbe (Tajikistan), and Tashkent (Uzbekistan). The results show severe air quality deterioration in the cities with annual PM2.5 concentrations up to ten-fold higher than the limits. A clear seasonal pattern with winter peaks was observed in Almaty, Bishkek, and Astana, whereas winter and summer were highly polluted in Tashkent and Dushanbe. Based on the pollution profiles, cities were classified into several clusters. Episodes with high PM2.5 concentrations were evaluated for regional pollutant transportation using the HYSPLIT model. The results of this investigation highlight a significant discrepancy in official emissions inventory studies. While previous studies have suggested that transportation is the primary source of air pollution, the approach to estimate the share of emission sources was based on an outdated methodology that obscures information on the most hazardous pollutants, including PM2.5. This study shows that coal combustion is the primary source of PM2.5 pollution in most cities, offering policymakers critical insights into the sources of air pollution in the region. These findings demonstrate the need for policymakers to take swift action to address coal use and adopt effective measures to mitigate PM2.5 pollution, thereby improving the health and well-being of the population.
ABSTRACT
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 NO2 and CO levels was observed in 5 and 3 cities, respectively (out of 8). Total Suspended Particles and SO2 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. Highlights Response of air quality to COVID-19 lockdown in eight cities of Kazakhstan was examined The positive effect of the COVID-19 lockdown on NO2 and CO was observed in 5 and 3 cities, respectively The effect of the quarantine measures on SO2 and TSP was different in different cities Industrial cities were not affected by the lockdown, but seasonal changes were significant NO2 and SO2 concentrations exceeded the WHO limits during the COVID-19 lockdown period Supplementary Information The online version contains supplementary material available at 10.1007/s40710-022-00603-w.