2013年1月29日11时,来自北京各监测站点实时数据显示:全市PM2.5近一小时均值突破350μg/m3,质量状况为“严重污染”。这是2013年1月以来雾霾第四次侵扰京城,当天北京发布霾黄色预警,预计大部分地区将维持能见度小于3000米的霾。而持续雾霾天气造成的空气污染,使得舆论对“污染源”的讨论持续发酵。北京市环保局大气处处长于建华在 At 11:00 on January 29, 2013, real-time data from all monitoring stations in Beijing showed that the average PM2.5 in the whole city exceeded 350 μg / m3 in the past hour and the quality condition was “serious pollution”. This is the fourth haze of the haze that has invaded the capital since January 2013, when Beijing issued a yellow haze warning. It is estimated that haze will be maintained in most areas with a visibility of less than 3,000 meters. The air pollution caused by the continuous haze weather, making the public opinion on “pollution source ” discussion continues to ferment. Beijing Municipal Environmental Protection Bureau Director of Atmosphere at Jianhua Yu