The National Committee on Ecology and Climate Change of Uzbekistan reported that the atmospheric air quality in Tashkent may temporarily worsen during nighttime and morning hours until the end of the current week.
According to the agency's data, on October 6, the air quality level across most of Tashkent was rated as 'moderate' according to the international AQI index. However, after 8:00 PM, indicators began to deteriorate, and during nighttime and morning hours, a level considered 'unfavorable for sensitive groups' was recorded over a wider area. In some districts, a brief 'unhealthy' pollution level was observed.
Between 5:00 PM on October 6 and 10:00 AM on October 7, the average concentration of fine particulate matter PM2.5 in the city reached 43.5 µg/m³, and PM10 reached 97.2 µg/m³. The average AQI for this period was 117, corresponding to the 'unfavorable for sensitive groups' category. Under national indexing, the PM2.5 concentration was within the 'green' level, while PM10 was at the 'yellow' level.
By 10:00 AM on October 7, the average PM10 level in the city rose to the 'orange' level. The Committee explained the air quality deterioration due to unfavorable meteorological conditions that restricted the dispersion process of pollutants. Factors included low wind speed, around 1 m/s, and strong nocturnal temperature inversion, which led to reduced air exchange and vertical mixing.
Temperature inversion was observed between 11:00 PM on October 6 and 8:00 AM on October 7. The temperature difference in the inversion layer reached 1.8–6.7 degrees, which is classified as strong inversion. Under such conditions, a layer of warmer air forms above the cold air near the surface, hindering the vertical dispersion of pollutants, the committee explained. Committee representatives warned that such phenomena may occur periodically during nighttime and morning hours until the end of the week.