National Committee on Ecology and Climate Change of the Republic of Uzbekistan

This warming contributed to the advance of westerly pre-frontal winds from a cold anticyclone with a central pressure of up to 1028 hPa, which was moving across the Caspian Sea on the night of 21 September.

During the day on 21 September and in the morning of 22 September, strong westerly winds in the eastern part of Navoi region and around the Aydarkul lake system shifted direction, originating from the Chardarya Reservoir and moving northward. In the second half of 22 September, dust masses lifted from eastern Kyzylkum, the Aydarkul area and southern Kazakhstan reached Tashkent.

From 15:00 on 22 September, concentrations of fine particulate matter (PM2.5 and PM10) began  to increase in the southwestern districts of the capital. The Horiba automatic station near the Uchtepa district administration recorded  142 µg/m³ of PM2.5 — four times higher than the national standard (35 µg/m³).

By 16:00, southwesterly winds at 4 m/s carried the dust particles into the central and northeastern parts of the city. At the “Yangi Uzbekistan” Park, the monitoring station recorded PM2.5 levels twice the permissible concentration (68 µg/m³). At the same time, visibility at Tashkent International Airport decreased to 5 km.

By 18:30, readings from automatic stations across the city showed a sharp increase in PM2.5 concentrations, reaching 150 µg/m³ — five times the national standard. Visibility at the airport further declined to 4 km.

Forecast

A cold anticyclone with a pressure of up to 1025 hPa is passing over the central regions of the republic and will determine weather conditions until 24 September. However, it will not be able to completely clear Tashkent’s atmosphere of accumulated particles. On the contrary, airflows are expected to gradually deposit them closer to the surface. During the morning and evening hours of 23–24 September, inversions may cause PM2.5 levels to rise again. Only on the night of 24 September, with the departure of the anticyclone and the arrival of new cyclonic systems, is a rapid improvement in air quality in the capital expected.