今年前8个月北京PM2.5平均浓度同比下降17.2% 中新网北京9月15日电 (记者 陈杭)记者15日从北京市生态环境局获悉，今年1-8月，北京市细颗粒物 (PM2.5)平均浓度为25.6微克/立方米，同比下降17.2%；优良天数198天，同比增加20天。其中，8月份全 市PM2.5月均浓度16.7微克/立方米。 车械新能源化显著提速 北京市生态环境局表示，北京市组织实施小汽车以旧换新、国四及以下排放标准老旧货车和大中型客车 报废更新等政策，推动5000余辆国四及以下老旧客货车申请"油换电"补贴。持续实施本市五环路内新能 源物流配送车辆优先通行政策，激励货车新能源化。通过资金激励、重点领域先行带动等方式，推动城 市配送、商超等重点领域新能源化，建立主要由新能源车组成的清洁运输车队，多家大型物流企业实现 城市配送的轻型车新能源化。全市新能源汽车保有量达到116万余辆。 加快实施非道路移动机械清洁化工作方案，持续开展新一轮扩大高排放非道路移动机械禁用区政策宣传 解读，促进老旧机械淘汰。非道路移动机械新能源化率提升至40%以上。 企业提级创绿步伐加快 北京市综合运用清洁生产审核、"一厂一策"治理、绿色绩效评价等措施 ...

联合国官员：北京空气污染治理为世界提供宝贵经验 中新网北京9月4日电 (记者 官逸伦)"北京的空气污染治理历程为世界各地致力于获得清洁空气的城市和 国家提供了宝贵经验。"联合国驻华协调员常启德4日在北京如是说。 9月4日，联合国驻华协调员常启德在北京出席2025年"国际清洁空气蓝天日"主题活动并作开幕致辞。 (联合国环境规划署驻华代表处供图) 由联合国环境规划署驻华代表处主办的2025年"国际清洁空气蓝天日"主题活动当日在中国北京举行。 常启德表示，作为中国在空气污染治理方面取得进展的例证之一，北京的空气质量较数十年前有了明显 提升。"在北京，政府、社区和其他利益相关方经过数十年的坚定努力，已经证明清洁空气是可以实现 的。" 编辑：万可义 广告等商务合作，请点击这里 本文为转载内容，授权事宜请联系原著作权人 中新经纬版权所有，未经书面授权，任何单位及个人不得转载、摘编或以其它方式使用。 关注中新经纬微信公众号(微信搜索"中新经纬"或"jwview")，看更多精彩财经资讯。 在常启德看来，北京取得的进步源于持续的投资、有力的政策，"最重要的是，非常坚定的政治意愿"。 他呼吁全球相关方加快采取集体行动，寻找应对空 ...

Core Viewpoint - Air pollution is a global environmental issue with significant impacts on air quality, climate, ecosystems, and human health. China's severe smog pollution, characterized by high PM2.5 concentrations, has shown improvement since 2013 due to regulatory measures [2][3]. Group 1 - The unique formation mechanism of smog in China involves both high-intensity primary pollutant emissions and efficient secondary transformation processes [2][3]. - The current stage in China is marked by a mix of agricultural and industrial societies, leading to high emissions of secondary aerosol precursors from various sources, including ammonia from agricultural activities and nitrogen oxides from industrial activities [3][4]. - A recent review published in the journal Science highlights the complex interactions of multiple atmospheric factors contributing to the unique formation mechanism of secondary organic aerosols (SOA) in urban China [4][10]. Group 2 - Despite significant progress in environmental pollution control over the past decade, uncertainties remain regarding the precursors, formation processes, and impacts of SOA on radiation budgets and human health in Chinese cities [6][9]. - The substantial decrease in PM2.5 concentrations in urban China has led to a significant increase in ground-level ozone concentrations, which facilitates SOA formation [6][9]. - Understanding the sensitivity of ozone-nitrogen oxides-volatile organic compounds in urban areas is crucial for developing economically effective strategies to control precursors that lead to high concentrations of both SOA and ozone [6][9]. Group 3 - The study identifies that high atmospheric oxidation capacity in winter results from various factors, including high concentrations of gas-phase nitrous acid photolysis and nitrogen oxides participating in olefin ozonolysis [7][9]. - The increase in nitrate proportions has also enhanced the liquid water content of aerosols, further promoting the generation of liquid-phase SOA [7][9]. - Future research should focus on exploring unknown oxidation pathways, characterizing precursors and multi-generation oxidation products at the molecular level, and understanding the corresponding generation and aging mechanisms [7][9]. Group 4 - The paper summarizes the scientific status of SOA formation in urban China, emphasizing the dominant role of anthropogenic precursors, the main mechanisms of SOA formation, and the importance of multi-pollutant and multiphase processes in SOA evolution [9][10]. - This research deepens the understanding of the formation mechanisms of haze pollution in China and provides a reference for global atmospheric pollution studies, offering important scientific basis for future air pollution control and policy-making [10].