Seasonal and Spatial Variation of Volatile Organic Compounds in Ambient Air of Almaty City, Kazakhstan

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.

Distribution and temporal variation of total volatile organic compounds concentrations associated with health risk in Punjab, India

“…The highest value of BTEX was observed at Amritsar, while the lowest was in Khanna. The high level at Amritsar during the lockdown may be because of the stubble or biomass burning cases, rubber and pharmaceutical industries, and limited transportation activities of essential duty and supply vehicles (Truc & Oanh, 2007;Ibragimova et al, 2021;Rathod et al, 2021;Sahu et al, 2022).…”

“…A less than 1 T/B ratio shows non-tra c sources such as coal burning, biomass, and bio-fuel, while the value of T/B ratio is more than 1, it indicates the major contribution of tra c-related sources. When vehicle emissions act as a major BTEX source which is commonly seen, the T/B ratio was reported low (Ibragimova et al, 2021). Before the pandemic, the toluene and benzene (T/B) ratio was calculated for the different monitoring stations and were observed, 0.57 µg/m 3 for Amritsar, 1.38 µg/m 3 for Ludhiana and 2.97 µg/m 3 for Patiala, which indicates non-tra c related sources such as biomass, coal burning and biofuel in Amritsar and Ludhiana (Ibragimova et al 2021).…”

“…A Higher T/B ratio was found in Patiala (2.97 µg/m 3 ) before the pandemic, which may indicate vehicle (tra c) emission sources and evaporative emission of solvent (Sarp et al, 2020;Ibragimova et al, 2021).…”

Seasonal Variations and Effect of COVID-19 Lockdown Restrictions on the Air Quality in the Cities of Kazakhstan

“…In Kazakhstan, the impact of COVID-19 restriction measures on air quality was studied in two cities: Almaty (Kerimray et al 2020b ; Ibragimova et al 2021 ) and Ust-Kamenogorsk (Assanov et al 2021b ). Assanov et al ( 2021b ) reported that the concentration of Total Suspended Particles (TSP) increased by 13–21%, while SO 2 and NO 2 levels did not change significantly in Ust-Kamenogorsk (Kazakhstan) during the lockdown.…”

“…In Almaty (Kazakhstan), concentrations of CO, NO 2, and PM 2.5 decreased by 49, 35 and 21%, respectively, with an insignificant increase of SO 2 (Kerimray et al 2020b ). The changes of volatile organic compound concentrations during the lockdown in Almaty showed an increase in the levels of benzene and toluene by 2–3 times (Kerimray et al 2020b ) and in the levels of ethylbenzene and benzaldehyde by 2–5 times (Ibragimova et al 2021 ). Thus, air pollution could be substantially improved during the lockdown in the cities where transport was a major source.…”