Insight into characteristics and sources of PM2.5 in the Beijing-Tianjin-Hebei region, China

As the world's second-largest economy, China has experienced severe air pollution with unprecedentedly high levels of PM_(2.5), i.e. particulate matter smaller than 2.5 μm in diameter. The Ministry of Environmental Protection of China released an air pollution monitoring report for the year 2013 for the 74 largest cities of China. The Beijing-Tianjin-Hebei (BTH) region was classified as having the poorest air quality. The annual average PM_(2.5) concentration of the 13 cities in the BTH region was 106 μg/m~3. None of these cities met the new annual China Ambient Air Quality Standard (CAAQS), and 10.4-79.2% of the total days in 2013 met the daily CAAQS. Seven cities ranked in the top 10 with poorest air quality in the country. In January 2013, there were severe regional haze events in the BTH region, with the highest hourly PM_(2.5) concentration in Beijing exceeding 900 μg/m~3.SCI(E)中国科学引文数据库(CSCD)EDITORIAL MATERIALminhu@pku.edu.cn; songguo@geos.tamu.edu3257-258