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投稿时间：2015-07-30 修订日期：2016-06-01
投稿时间：2015-07-30 修订日期：2016-06-01
中文摘要: 利用2005—2014年北京宝联（城区）和2006—2014年上甸子本底站（郊区）的PM2.5质量浓度监测结果揭示了其长时间的演变特征。结果表明，2005—2007年北京地区PM2.5污染最重，2008年以后PM2.5年平均浓度明显降低，中度以上污染日数减少，但是2013—2014年有加重趋势。城区秋、冬季平均浓度最高，春季和夏初次之。然而，近年来春、夏季污染有减轻的趋势，高浓度值出现的时间越来越向秋、冬季集中，从而导致季节性差异变大。春季沙尘天气是其影响因素之一。上甸子春、夏季的PM2.5平均浓度高于秋、冬季，与城区不同。但2011年以后城郊差异逐渐变小，表明污染事件的区域性特征增强。北京城区中度污染日数年平均为30 d，重度污染为26 d，严重污染为4.7 d。污染日数月际变化明显并且月分布具有年际差异。2013—2014年，中度污染日数减少，严重污染日数增加，PM2.5年平均浓度与秋、冬季重污染过程的相关性增大。上甸子中度以上污染日数是城区的1/3。持续性重污染过程多发生在秋、冬季。2008—2014年以后中度以上污染持续超过3 d的过程每年平均发生1.9次，重度以上污染0.6次。绝大多数严重污染只持续2~3 d。重度以上污染日多出现在污染过程的中后期，因此遇不利气象条件提前采取减排措施将有可能减少重污染发生的频次。
Abstract:The PM2.5 mass concentration data from Baolian Atmospheric Composition Monitoring Station, which represents urban area, in 2005-2014 and the data from Shangdianzi BAP Station, which represents rural area, from 2006 to 2014 are used to analyze its long term temporal evolvement in Beijing. The results show that the PM2.5 pollution was the severest during 2005-2007. Since 2008, the annual mean mass concentration and the days of moderate pollution or over have been reduced, but the situation became worse from 2013 to 2014. The average mass concentration in urban area was the highest in winter and autumn, and took the second place from spring to the early of summer. However, in recent several years, such pollution tends to be reduced somewhat in spring and summer. At the same time, high mass concentration was found more often in autumn, which enlarges the seasonal gap. One impact factor is the sand dust weather in spring. At Shangdianzi Station, the rural area, the annual mean mass concentration is higher in spring and summer, different from that in urban area. But since 2011, the above difference has become much smaller. This indicates that the regional pollution takes place more commonly. On average, there are 30 pollution days at moderate level, 26 days at severe level and 4.7 days at extreme level every year. However, there is some monthly and annual discrepancies of this characteristic. Besides, the moderate pollution cases decreased while severe ones increased in 2013 and 2014. Therefore, the annual mean mass concentration has higher relationship with the severe pollution events in winter and autumn. The moderate or severe pollution days in Shangdianzi are only 1/3 of that in urban area. Moreover, the persistent pollution event appears in winter and autumn normally. The annual average times of pollution events which last at least 3 days are 1.9 for moderate level and 0.6 for severe level during 2008-2014. Most extreme events could cover 2 to 3 days only. Based on the statistics, the mass concentration often reaches severe grade or above after the middle stage of the event. So, it might reduce the possibility of severe pollution by controlling emission in advance when the meteorological condition is not favorable for the diffusion of pollutants.
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基金项目:国家科技支撑计划项目（2014BAC16B04）和国家级雾霾监测与预报团队共同资助
| 作者 | 单位 |
| 苗蕾 | 中国气象科学研究院，北京 100081 中国气象局北京城市气象研究所，北京 100089 |
| 廖晓农 | 中国气象科学研究院，北京 100081 中国气象局北京城市气象研究所，北京 100089 |
| 王迎春 | 北京市气象局，北京 100089 |
| 赵春生 | 北京大学物理学院，北京 100871 |
引用文本：
苗蕾,廖晓农,王迎春,赵春生,2016.北京2005—2014年PM2.5质量浓度的演变特征[J].气象,42(8):954-961.
MIAO Lei,LIAO Xiaonong,WANG Yingchun,ZHAO Chunsheng,2016.Evolution Characteristics of PM2.5 Mass Concentration in Beijing During 2005-2014[J].Meteor Mon,42(8):954-961.
苗蕾,廖晓农,王迎春,赵春生,2016.北京2005—2014年PM2.5质量浓度的演变特征[J].气象,42(8):954-961.
MIAO Lei,LIAO Xiaonong,WANG Yingchun,ZHAO Chunsheng,2016.Evolution Characteristics of PM2.5 Mass Concentration in Beijing During 2005-2014[J].Meteor Mon,42(8):954-961.