China News Service, October 26. According to the WeChat official account of the Ministry of Ecology and Environment, the Ministry of Ecology and Environment today announced to the media the national ambient air quality status in September 2026 and January to September. The specific contents are as follows:
air quality
Overall situation
In September, the average concentration of PM2.5 in 339 cities at the prefecture level and above was 19.0 micrograms/cubic meter, a year-on-year increase of 18.8%; the average PM10 concentration was 35 micrograms/cubic meter, a year-on-year increase of 12.9%; the average O3 concentration was 140 micrograms/cubic meter, a year-on-year increase of 17.6%; the average SO2 concentration was 7 micrograms/cubic meter, unchanged year-on-year; the average NO2 concentration was 13 micrograms/cubic meter, a year-on-year decrease of 7.1%; the average CO concentration was 0.7 mg/cubic meter, unchanged year-on-year.
In September, the average proportion of days with good air quality in 339 cities at the prefecture level and above across the country was 92.3%, a year-on-year decrease of 3.5 percentage points; the average proportion of days with severe and above pollution was 0.1%, a decrease of 0.5 percentage points from the same period last year. The average proportion of days exceeding the standard caused by sand and dust weather was 0.4%, of which the proportion of days with severe and above pollution was 0.1%.
From January to September, the average PM2.5 concentration in 339 prefecture-level and above cities across the country was 24.9 micrograms/cubic meter, a year-on-year decrease of 3.9%; the average PM10 concentration was 42 micrograms/cubic meter, a year-on-year decrease of 6.7%; the average O3 concentration was 139 micrograms/cubic meter, a year-on-year decrease of 2.8%; the average SO2 concentration was 7 micrograms/cubic meter, the same as the same period last year; the average NO2 concentration was 15 micrograms/cubic meter, a year-on-year decrease of 11.8%; the average CO concentration was 0.9 mg/cubic meter, the same as the same period last year.
From January to September, the average proportion of days with excellent air quality in 339 cities at the prefecture level and above across the country was 86.6%, a year-on-year increase of 2.8 percentage points; the average proportion of days with severe and above pollution was 0.7%, a year-on-year decrease of 0.4 percentage points. The average proportion of days exceeding the standard caused by sand and dust weather was 2.9%, of which the proportion of days with severe and above pollution was 0.5%.
Figure 1 Proportion of days at each level in 339 prefecture-level and above cities across the country from January to September 2026 Source: WeChat official account of the Ministry of Ecology and Environment
Figure 2 Concentrations and year-on-year changes of six indicators in 339 cities at prefecture level and above across the country from January to September 2026 Source: WeChat official account of the Ministry of Ecology and Environment
key areas
(1) Beijing-Tianjin-Hebei and surrounding areas
In September, the average concentration of PM2.5 in the "2+36" cities in Beijing-Tianjin-Hebei and surrounding areas was 28.7 micrograms/cubic meter, a year-on-year increase of 32.9%; the average O3 concentration was 180 micrograms/cubic meter, a year-on-year increase of 17.6%; the average proportion of good days was 72.0%, a year-on-year decrease of 18.2 percentage points; there were no severely polluted days or above, which was the same as the same period last year. There were no excessive days caused by sand and dust weather.
From January to September, the average concentration of PM2.5 in the "2+36" cities in Beijing-Tianjin-Hebei and surrounding areas was 37.0 micrograms/cubic meter, a year-on-year increase of 12.1%; the average O3 concentration was 169 micrograms/cubic meter, a year-on-year decrease of 2.9%; the average proportion of good days was 68.4%, a year-on-year increase of 0.9 percentage points; the average proportion of severely polluted days and above was 0.9%, a year-on-year increase of 0.1 percentage points. The average proportion of days exceeding the standard caused by sand and dust weather was 2.0%, of which the proportion of days with severe and above pollution was 0.1%.
In September, the PM2.5 concentration in Beijing was 20.1 micrograms/cubic meter, a year-on-year increase of 0.5%; the O3 concentration was 173 micrograms/cubic meter, a year-on-year increase of 21.0%; the proportion of good days was 83.3%, a year-on-year decrease of 10.0 percentage points; there were no severely polluted days or above, which was the same as the same period last year. There were no excessive days caused by sand and dust weather.
From January to September, the PM2.5 concentration in Beijing was 26.9 micrograms/cubic meter, a year-on-year increase of 8.0%; the O3 concentration was 162 micrograms/cubic meter, a year-on-year decrease of 4.7%; the proportion of good days was 82.1%, a year-on-year increase of 1.5 percentage points; there were no severely polluted days or above, a year-on-year decrease of 0.4 percentage points. The proportion of days exceeding the standard caused by sand and dust weather was 0.7%, and there were no days with severe or above pollution.
(2) Yangtze River Delta region
In September, the average concentration of PM2.5 in 31 cities in the Yangtze River Delta was 18.6 micrograms/cubic meter, a year-on-year increase of 8.8%; the average O3 concentration was 149 micrograms/cubic meter, a year-on-year increase of 2.8%; the average proportion of good days was 91.8%, a year-on-year decrease of 1.9 percentage points; there were no severely polluted days or above, which was the same as the same period last year. There were no excessive days caused by sand and dust weather.
From January to September, the average PM2.5 concentration in 31 cities in the Yangtze River Delta region was 28.0 micrograms/cubic meter, a year-on-year decrease of 5.4%; the average O3 concentration was 155 micrograms/cubic meter, a year-on-year decrease of 6.1%; the average proportion of good days was 81.6%, a year-on-year increase of 4.7 percentage points; the average proportion of severely polluted days and above was 0.1%, a year-on-year decrease of 0.1 percentage points. The average proportion of days exceeding the standard caused by sand and dust weather was 0.8%, of which the proportion of days with severe and above pollution was 0.1%.
(3) Fenwei Plain
In September, the average concentration of PM2.5 in 13 cities in the Fenwei Plain was 25.9 micrograms/cubic meter, a year-on-year increase of 23.9%; the average O3 concentration was 161 micrograms/cubic meter, a year-on-year increase of 18.4%; the average proportion of good days was 87.7%, a year-on-year decrease of 10.2 percentage points; there were no severely polluted days or above, which was the same as the same period last year. There were no excessive days caused by sand and dust weather.
From January to September, the average concentration of PM2.5 in 13 cities in the Fenwei Plain was 31.7 micrograms/cubic meter, a year-on-year increase of 1.9%; the average O3 concentration was 162 micrograms/cubic meter, a year-on-year decrease of 2.4%; the average proportion of good days was 73.1%, a year-on-year increase of 4.3 percentage points; the average proportion of severely polluted days and above was 0.8%, a year-on-year decrease of 1.2 percentage points. The average proportion of days exceeding the standard caused by sand and dust weather was 6.3%, of which the proportion of days with severe and above pollution was 0.5%.
Figure 3 Comparison of air quality across the country and key regions from January to September 2026 Source: WeChat official account of the Ministry of Ecology and Environment
key cities
The comprehensive ambient air quality index and PM2.5 concentration status of 168 key cities in September and January to September are detailed in the attached table.
