Comparative study of outdoor air pollution in Ulaanbaatar and Darkhan

Abstract

Background: In 2018, the Government of Mongolia approved Resolution No. 62 “Prohibiting the use of raw coal” and began to implement it from May 15, 2019. According to this law, households in Ulaanbaatar use processed coal, but Darkhan city still uses raw coal. The paucity of air pollution studies comparing the use of processed coal with raw coal prompted this study. Aim: To compare outdoor air pollutants PM2.5, PM10 and NO2 in 2014-2021 in Ulaanbaatar and Darkhan cities. Materials and Methods: The research was carried out using a fact-finding model based on the integrated statistical data of the Ministry of Education and Culture. The pollutants of PM2.5, PM10 and NO2 particles in the air of the cities of Ulaanbaatar and Darkhan compared to before and after the 2014-202, Covid-19 pandemic. In Ulaanbaatar 18 and 2 in Darkhan air quality monitoring stations were shown to monitor the air condition and pollutants. Analysis of quantitative air quality data was performed using statistical processing software R. Results: In the winter of 2020, the average concentration of fine particles in the air of Ulaanbaatar city decreased by 82.4 μg/m3 or 59.6% compared to the average concentration in the same period of the previous year. The concentration of fine particles in the air of Darkhan increased by 18.9 μg/m3 or 35.6% compared to the same period of the previous year. In the winter of 2020, the average concentration of large particles in the air of Ulaanbaatar city decreased by 121 μg/m3 or 65.7% compared to the average concentration in the same period of the previous year. The concentration of large particles in the air of Darkhan increased by 49.6 μg/m3 or 37.3% compared to the same period of the previous year. NO2 concentration in the air of Ulaanbaatar and Darkhan tend to increase in the future. Darkhan city’s average NO2 concentration is 25.48μg/ m3 and Ulaanbaatar city’s yearly concentration was 25.80μg/m3. Conclusions: According to the aggregated data from air quality monitoring stations in Ulaanbaatar and Darkhan cities, fine PM2.5 particles are caused by the burning of raw coal and processed coal. Since the curfew was imposed, the number burning coal increased and the amount of air pollutants has increased. However, PM10 particles contain more soil-derived elements, which decreased due to reduced and stopped trafÏc during the pandemic.