In November 2024, China experienced weaker cold air activity and higher temperatures. The prevailing southeast winds not only pushed regional pollutants into northern China but also raised humidity levels, resulting in smog drifting toward the west and north. A total of 81 cities, including Beijing and Shijiazhuang, saw their PM2.5 concentrations rise by 5 micrograms or more compared to the same period last year. Due to factors such as straw burning, cities like Suihua, Harbin, Daqing, and Qiqihar experienced relatively severe pollution, with PM2.5 concentrations rebounding. In Suihua, the monthly average PM2.5 level reached 111 μg/m3, a 127.5% year-on-year surge. In central China, cities such as Xiangtan, Yiyang, and Changsha also saw significant increases in pollution levels. In contrast, the prevalence of southeast winds contributed to notable improvements in the Yangtze River Delta and Pearl River Delta regions. Nationwide, a total of 122 cities saw PM2.5 concentrations drop by 5 micrograms or more, with improvements mainly in areas such as Sichuan, Anhui, Zhejiang, and Jiangsu.

From October to early November, many northern regions experienced three rounds of pollution, occurring one to two weeks earlier than the five-year average. Experts from the China National Environmental Monitoring Center, led by Wang Wei, summarized it as arriving early, lasting longer, and being more severe. According to #Blue Map# hourly dynamics, changes in meteorological conditions showed significant regional transmission of haze. Professor Wang Shuxiao from Tsinghua University’s School of Environment explained that under the sustained weak pressure system, southerly winds and high humidity caused long-distance transmission of regional pollution and local accumulation. Analysis of the nitrate proportion in PM2.5 components during the pollution process suggests that emissions of NOx from key industrial sectors and diesel trucks, along with their chemical transformation, remain the main causes of the pollution.

In September, conditions were generally favorable for diffusion in northern regions, with Beijing’s monthly PM2.5 concentration at just 17 micrograms, a 40.4% decrease compared to the same period last year. Meanwhile, the Yangtze River Basin experienced an unusually prolonged heatwave. The southern autumn typhoon season was notably active, with Typhoons "Capricorn," "Bebinca," and "PraSan" following one after another, and their intensity surpassing historical averages for the same period.

In August, precipitation in the Haihe River Basin in North China was 78.5% above average, and rainfall also exceeded normal levels in the Liaohe, Songhua, and Yellow River basins. Correspondingly, particulate matter concentrations in key northern regions generally decreased year-on-year. In contrast, precipitation in the southern regions—specifically the Yangtze, Huaihe, and Pearl River basins—was below average, with the Yangtze River Basin experiencing a 45.3% shortfall, the second-lowest in history, surpassed only by 2022. As a result, the south endured prolonged high temperatures, driving the national average temperature in August 1.5°C above the average, marking the highest level since 1961.

In July, extreme heat and heavy rain alternated, significantly impacting urban air quality due to meteorological factors. National PM2.5 concentrations dropped to 16 micrograms, with 68 cities reporting levels below 10 micrograms. In the northeast, particulate matter levels were elevated due to smoke from Siberian wildfires, with cities like Daqing, Daxing'anling, Harbin, and Heihe recording their highest monthly PM2.5 concentrations since 2015. Meanwhile, national ozone concentrations decreased to 131.8 micrograms, marking the lowest level for the same period since 2015.

In June, continuous rainfall in the south led to widespread air quality improvements. However, some regions experienced flooding disasters. Statistics show that the monthly PM2.5 concentration in 100 cities nationwide reached its lowest level on record, with the average monthly PM2.5 in 28 southern cities falling below 10 micrograms. Meanwhile, in the north, high temperatures caused repeated ozone spikes in key areas, and PM2.5 levels in the Beijing-Tianjin-Hebei region and surrounding areas also saw a year-on-year rebound.

The 2023 China Ecological Environment Bulletin has been released, showing that the national air quality continues to improve over the long term. In 2023, the average PM2.5 concentration across 339 cities was 30 micrograms. In key air pollution control regions such as the Beijing-Tianjin-Hebei area and the Fenwei Plain, the average PM2.5 concentration dropped by 2.3% and 6.5% year-on-year, respectively. #BlueMap features dynamic air quality maps based on data from over 9,000 monitoring stations, providing hourly visualizations of air quality in May.