The Beijing-Tianjin-Hebei region and surrounding cities have been experiencing persistent air pollution since 23 October, according to The Paper.
Wang Wei, a senior engineer at China’s National Environmental Monitoring Centre, said that this pollution episode began 1-2 weeks earlier than usual. By 30 October, the “2+36” cities – Beijing, Tianjin, and 36 surrounding cities for which air pollution control is prioritised – had cumulatively experienced 31 days of moderate to heavy pollution.
Before this pollution had fully cleared, the region experienced another episode of moderate to heavy pollution, from 31 October to 2 November.
Wang Shuxiao, a professor at Tsinghua University’s School of Environment, told the media that low wind speeds and high humidity in the region have created conditions that make it difficult to clear smog.
In the last episode of pollution, PM2.5 particles were found to contain high levels of nitrates and other secondary ions, that are produced via atmospheric reactions of gases such as nitrogen oxides (NOx), reaching 38% and over 50% respectively. This indicates that NOx, which are emitted from industrial activities and diesel vehicles, rapidly converted under static, high-humidity conditions, and were a significant contributor to the pollution.
To mitigate the pollution, local governments enacted strict emissions controls on key industries and diesel trucks. By 3 November, air quality in Beijing and surrounding areas had improved significantly, although the central and southern regions continued to experience moderate pollution which is expected to persist until mid-November, according to China Environment News.
Since China implemented its “Air pollution prevention and control action plan” in 2013, air quality has improved considerably. However, Qiu Chengcheng, an analyst at the Centre for Research on Energy and Clean Air (CREA), pointed out that after falling for a decade, China’s PM2.5 levels rebounded in 2023 due to increased human activity and unfavourable weather conditions.
Qiu also noted that the national standard for PM2.5 concentration, at 35 µg/m3, is still more relaxed than the World Health Organization’s recommended level of 5 µg/m3. While she welcomed the government’s plans to set Beijing’s target at 32µg/m3 by 2025, Qiu highlighted that “the central government will need strict enforcement to improve air quality and to adjust to a sustainable and high-quality development model” to achieve this.
Read Dialogue Earth’s earlier report on how climate change complicates China’s ‘battle for blue skies’