Why this is happening?

The graph 1 shows the higher concentration of air pollutans during winter, becase of need to heat up buildings, especially the older buildings. Also, coal combustion and fossil fuel combustion are the cheapest electricity generators compared to renewable energy sources. The Geographical location of Almaty provides the understanding of air pollution in this region. Almaty is located in the foot of Trans-Ili Alatau. Hence, the city is surrounded by mountains and hills, this location prevents horizontal movement of air. (Lars Carlsen, Bulat N. Kenessov,Nassiba Kh. Baimatova*, Olga A. Kenessova 2013). Temperature inversion is a weather phenomenon, which occurs in Almaty due to geographical location. Since Almaty lies in a valley, the bowl-shaped terrain traps cold air in the surface. Warm air lies above the cold air, preventing cold air to rise. While cold air that is locked between ground and warm air trap air pollutants near the surface, the  air pollutans such as Sulfur dioxide ( SO2), Carbon monoxide (CO) and Particulate matter (PM2.5 PM10) build up on each other, worsening the air quality. During winter, sutuation becomes worse, because the nights last longer, it allows ground to cool efficiently. Eventually, coal combustion plants and car emissions are the major contributors to air pollution. Air pollutants such as Sulfur dioxide (SO2), Nitrogen Oxides (NO) contribute to respiratory illnesses and worsen them.