Ravkat Mukhtarov ^a, Olga P. Ibragimova ^a, Anara Omarova ^{a b}, Madina Tursumbayeva ^{a c}, Kazbek Tursun ^a, Aset Muratuly ^a, Ferhat Karaca ^{d e}, Nassiba Baimatova ^{a b}

Abstract
PM_2.5 pollution is a severe problem in most cities in Kazakhstan and is a leading cause of premature deaths globally. This study examines the temporal variation of PM_2.5 levels and the effect of air mass transportation dynamics on episodic air pollution in Kazakhstan's two largest cities. In 2021 annual PM_2.5 concentrations in Astana (22.5 μg m⁻³) and Almaty (35.3 μg m⁻³) exceeded the annual WHO limit by 4.5 and 7.1 times, respectively. The daily limits surpassed 151 days in Astana and 217 days in Almaty. PM_2.5 levels were highest in winter averaging 35.3 μg m⁻³ (Astana) and 76.0 μg m⁻³ (Almaty) over the heating season, with coal combustion as a main contributor. The HYSPLIT model was used to assess the impact of air mass trajectories on pollution episodes and clean air events. Cluster and concentration-weighted trajectory analyses showed that air pollution episodes in both cities were associated with the anticyclone-blocking effect. While both cities were exposed to the influence of long-range transported pollutants, Astana was more frequently impacted by distant sources. Given the transboundary nature of air pollution in both cities and the complex relationship between meteorology and emission sources, a regional integrated air quality improvement strategy is needed.
https://doi.org/10.1016/j.uclim.2023.101541

Aiymgul Kerimray ^a, Nassiba Baimatova ^a, Olga P. Ibragimova ^a, Bauyrzhan Bukenov ^a, Bulat Kenessov ^a, Pavel Plotitsyn ^b, Ferhat Karaca ^{c d}


Abstract
Number of cities worlwide experienced air quality improvements during COVID-19 lockdowns; however, such changes may have been different in places with major contributions from nontraffic related sources. In Almaty, a city-scale quarantine came into force on March 19, 2020, which was a week after the first COVID-19 case was registered in Kazakhstan. This study aims to analyze the effect of the lockdown from March 19 to April 14, 2020 (27 days), on the concentrations of air pollutants in Almaty. Daily concentrations of PM_2.5, NO₂, SO₂, CO, O₃, and BTEX were compared between the periods before and during the lockdown. During the lockdown, the PM_2.5 concentration was reduced by 21% with spatial variations of 6–34% compared to the average on the same days in 2018–2019, and still, it exceeded WHO daily limit values for 18 days. There were also substantial reductions in CO and NO₂ concentrations by 49% and 35%, respectively, but an increase in O₃ levels by 15% compared to the prior 17 days before the lockdown. The concentrations of benzene and toluene were 2–3 times higher than those during in the same seasons of 2015–2019. The temporal reductions may not be directly attributed to the lockdown due to favorable meteorological variations during the period, but the spatial effects of the quarantine on the pollution levels are evidenced. The results demonstrate the impact of traffic on the complex nature of air pollution in Almaty, which is substantially contributed by various nontraffic related sources, mainly coal-fired combined heat and power plants and household heating systems, as well as possible small irregular sources such as garbage burning and bathhouses.
https://doi.org/10.1016/j.scitotenv.2020.139179

Abstract
Metal-organic frameworks have drawn increasing attention in the field of solid-phase microextraction due to their unique porous structure. Solid-phase microextraction coatings based on metal–organic frameworks exhibit large surface area (up to 1458 m²/g), high selectivity, stability (up to 270 extraction/desorption cycles), and extraction efficiency. Although there have been numerous studies on the synthesis of such fibers, many are not commercially available. In situ deposition from solution, chemical vapor deposition, electrodeposition, adhesion, sol-gel, and chemical bonding techniques are discussed among the methods reported to prepare coatings based on a metal–organic framework. Applications of these coatings for the measurement of volatile organic compounds, polycyclic aromatic hydrocarbons, persistent organic pollutants, phenols, and polychlorinated biphenyls are reviewed and critically discussed. The concluding remarks outline technical challenges and future potential of metal–organic framework based solid-phase microextraction fibers.

https://doi.org/10.1016/j.microc.2021.107147

Abstract
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.
https://doi.org/10.3390/atmos12121592
Keywords:
air quality; ambient air pollution; volatile organic compounds; monitoring; Almaty; Kazakhstan

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 PM_2.5 temporal variations and the influence of meteorological parameters on PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5. This study shows that coal combustion is the primary source of PM_2.5 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 PM_2.5 pollution, thereby improving the health and well-being of the population.
https://doi.org/10.1016/j.atmosenv.2023.119901

Abstract
Quantification of unsymmetrical dimethylhydrazine transformation products in solid samples is an important stage in monitoring of environmental pollution caused by heavy rockets launches. The new method for simultaneous quantification of unsymmetrical dimethylhydrazine transformation products in sand samples using vacuum-assisted headspace solid-phase microextraction without addition of water followed by gas chromatography-mass spectrometry is proposed. Decreasing air evacuation time from 120 to 20 s at 23 °C resulted in increased responses of analytes by 25–46% and allowed obtaining similar responses as after evacuation at −30 °C. The best combination of responses of analytes and their relative standard deviations (RSDs) was achieved after air evacuation of a sample (m = 1.00 g) for 20 s at 23 °C, incubation for 30 min at 40 °C, and 30-min extraction at 40 °C by Carboxen/polydimethylsiloxane (Car/PDMS) fiber. The method was validated in terms of linearity (R²=0.9912–0.9938), limits of detection (0.035 to 3.6 ng g⁻¹), limits of quantification (0.12–12 ng g⁻¹), recovery (84–97% with RSDs 1–11%), repeatability (RSDs 3–9%), and reproducibility (RSDs 7–11%). It has a number of major advantages over existing methods based on headspace solid-phase microextraction—lower detection limits, better accuracy and precision at similar or lower cost of sample preparation. The developed method was successfully applied for studying losses of analytes from open vials with model sand spiked with unsymmetrical dimethylhydrazine transformation products. It can be recommended for analysis of trace concentrations of unsymmetrical dimethylhydrazine transformation products when studying their transformation, migration and distribution in contaminated sand.
https://doi.org/10.1007/s11356-021-17844-1