Abstract: In recent years, Beijing-Tianjin-Hebei urban agglomeration has been seriously affected by fog and haze pollution, especially in winter heating period, and the air quality index has been seriously exceeding the standard. In order to alleviate the severe fog and haze caused by winter heating in Beijing-Tianjin-Hebei urban agglomeration, a clean energy heating policy was implemented in 2016. The changes of air quality in Beijing-Tianjin-Hebei urban agglomeration before and after the implementation of clean energy heating policy were compared and analyzed, and Mann-Kendall model was used to test the trend of air quality. The results show that: ① The air quality indexes (AQI, PM2.5, PM10, SO2, NO2 and CO) in the heating period after the implementation of clean energy in Beijing-Tianjin-Hebei region is lower than those before the implementation of clean energy. ② The comparative analysis of air quality shows that the implementation of clean energy can significantly promote the improvement of air quality. However, coal-fired heating in the past winter has actually exacerbated air pollution. ③ UF curves of six air quality factors (AQI, PM2.5, PM10, SO2, NO2 and CO) in Beijing from 2013 to 2018 are plotted by Mann-Kendall test. The results show that the variation characteristics of AQI, PM2.5 are similar, and the UF curves are almost the same, with mutations; the trend and mutation of PM10, NO2 and CO are strong; SO2 shows a downward trend, and no mutation occurs. Through the above analysis, it can be preliminarily predicted that the air quality index of Beijing will show a downward trend and a significant trend in the next few years. Therefore, it is urgent to use clean energy to improve air quality.

Key words: fog and haze, clean energy, air quality index, Mann-Kendall model

摘要： 京津冀地区近年来受到严重雾霾污染的影响，尤其是在冬季供暖时段空气质量指数更是严重超标。为缓解冬季供暖对京津冀地区带来的严重雾霾，国家于2016年实行了清洁能源供暖政策。笔者对比分析京津冀地区清洁能源供暖政策实施前后空气质量变化，并利用Mann-Kendall模型对空气质量进行趋势性检验。结果表明：①京津冀地区实行清洁能源后供暖期间的空气质量指标(AQI、PM2.5、PM10、SO2、NO2和CO)均小于实施清洁能源前；②空气质量的对比分析表明实施清洁能源可明显促进空气质量改善，以往冬季燃煤供暖确实加剧空气污染程度；③通过Mann-Kendall检验法，绘制2013—2018年北京市6种空气质量因子AQI、PM2.5、PM10、SO2、NO2和CO的UF曲线，结果表明AQI、PM2.5的变化特征相似，UF曲线大致相同，均有突变；PM10、NO2和CO的趋势性和突变性表现较强；SO2呈现下降趋势，无突变发生。通过以上分析可以初步预测使用清洁能源用于改善空气质量在接下来的几年内北京市空气质量指数会呈现下降趋势且趋势显著。

关键词: 雾霾, 清洁能源, 空气质量指数, Mann-Kendall模型