Reasons behind Tashkent’s air pollution revealed

Earlier, it was reported that Tashkent had ranked first in the world for air pollution. The Ministry of Ecology, Environmental Protection, and Climate Change provided an explanation regarding this situation.

According to the report, on September 21 of this year, a low-pressure atmospheric zone with a weak gradient, where the central pressure dropped to 1010 hPa, caused daytime air temperatures to rise to 34–35°C in Samarkand, Jizzakh, Syrdarya, and Tashkent regions. In some southern stations of the Tashkent region, maximum air temperatures exceeded 35°C.

This warming phenomenon on the night of September 21 was followed by the entry of cold anticyclonic activity from the Caspian Sea, where central atmospheric pressure rose to 1028 hPa, accompanied by persistent westerly winds in the region.

The strong and sustained westerly winds blowing across the eastern Navoi region on September 21 and the morning of September 22, and the Aydarkul lake system slightly shifted their direction northward, starting from the Choradara Reservoir area. By the afternoon of September 22, dust-laden air masses that had risen over eastern Kyzylkum, the Aydarkul area, and southern regions of Kazakhstan moved directly into Tashkent city.

Starting from 3:00 pm in Tashkent, concentrations of fine particulate matter PM2.5 and PM10 began to increase in the southwestern and western parts of the city. For instance, the Horiba automated station installed in front of the Uchtepa district administration building recorded PM2.5 levels of 142 µg/m³ during that period. This figure is four times higher than the national permissible standard, which is set at 35 µg/m³ for PM2.5.

At 4:00 pm, southwesterly winds in the capital were blowing at a speed of 4 meters per second, causing a rapid accumulation of fine particulate matter moving from the southwest toward the city center and northeast. During this period, PM2.5 and PM10 levels in central Tashkent also exceeded national permissible standards. Even in the eastern part of the city, at the automated monitoring station installed in the ’’New Uzbekistan’’ park, PM2.5 concentrations were recorded at 68 µg/m³, twice the national limit. As a result, dust-filled air began to spread across the city. From 4:00 pm, a dust phenomenon was also observed at Tashkent International Airport, where visibility was reduced to just 5 kilometers.

At 6:30 pm, data from several automated stations installed in Tashkent by Uzgidromet recorded a sharp increase in fine particulate matter, with PM2.5 levels reaching around 150 µg/m³. Such readings meant that air pollution across much of the city was up to five times higher than the national permissible standard. At the same time, visibility at Tashkent International Airport deteriorated further, dropping to 4,000 meters.

Forecast

A cold anticyclone with central atmospheric pressure rising to 1025 hPa is currently passing through the central part of the country. This system will influence the country’s weather until September 24, but it does not have the capacity to fully ’’clear’’ the fine particulate matter accumulated in Tashkent’s air on September 23–24. On the contrary, this air current is likely to gradually press the suspended particles closer to the ground. Due to temperature inversion during the morning and evening hours of September 23–24, concentrations of fine particulate matter in the air may increase further. However, by the night of September 24, with the complete retreat of the anticyclone from the region and the arrival of another low-pressure atmospheric system, Tashkent’s air may rapidly clear of fine particles.