A decade of air pollution control has largely restored the blue of Beijing\u2019s skies, but underneath the seemingly clear canopy another form of air pollution is creeping invisibly into the city.<\/p>\n\n\n\n
China\u2019s ozone concentration has risen steadily in the first half of this year. On 14 June, 42.4% of cities exceeded the national secondary ozone standard of 160 micrograms per cubic metre (\u00b5g\/m3<\/sup>), mainly in the Beijing-Tianjin-Hebei and Yangtze River Delta regions. Ozone has overtaken PM2.5 as the top pollutant affecting air quality, particularly in Beijing.<\/p>\n\n\n\n Ground-level ozone pollution occurs when certain chemicals in the air \u2013 volatile organic compounds and nitrogen oxides \u2013 react in sunlight. These two pollutants come from industrial emissions, car exhaust fumes and the evaporation of organic solvents, such as spray paint. They are closely linked with industries that have both high carbon emissions and high air pollution, often referred to in China as \u201ctwo high\u201d industries.<\/p>\n\n\n\n This year has seen normal life and economic activity restart after the pandemic lockdowns. While China\u2019s 14th Five Year Plan (for 2021-2025) set targets that would see carbon intensity and total coal consumption fall, the first half of 2023 has seen many provinces take advantage<\/a> of rules allowing these factors to be ignored when deciding on approvals for \u201cspecially designated projects<\/a>\u201d. This has resulted in approvals being granted to many coal power plants and \u201ctwo high\u201d projects, which means more industrial emissions. In the future, these extra emissions may worsen ozone pollution and environmental governance challenges.<\/p>\n\n\n\n It has been a decade since China declared war on air pollution, when the State Council published the country\u2019s first overarching, ten-point action plan<\/a>. That was followed in 2018 with a three-year action plan<\/a>, focusing on key areas including in and around the Beijing-Tianjin-Hebei region, the Fen and Wei river plains, and the Yangtze Delta. This intensified the fight against air pollution and consolidated existing achievements: average PM2.5 levels fell for ten years in a row, from 72 \u00b5g\/m3<\/sup><\/a> in 2013 to 29 \u00b5g\/m3<\/sup><\/a> in late 2022, lower than the World Health Organization\u2019s recommended 35 \u00b5g\/m3<\/sup>.<\/p>\n\n\n\nOzone now a major pollutant<\/h2>\n\n\n\n