| 2018~2020年北京市大气PM2.5污染特征及改善原因 |
| 摘要点击 4795 全文点击 2654 投稿时间：2022-05-22 修订日期：2022-08-10 |
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| 中文关键词 北京 污染特征 采暖季 PM2.5组分 空气质量改善 |
| 英文关键词 Beijing pollution characteristics heating season PM2.5 components improvement in air quality |
| 作者 | 单位 | E-mail | | 刘保献 | 清华大学环境学院, 北京 100084
北京市生态环境监测中心, 北京 100048
大气颗粒物监测技术北京市重点实验室, 北京 100048 | liubaoxian28@163.com | | 李倩 | 北京市生态环境监测中心, 北京 100048
大气颗粒物监测技术北京市重点实验室, 北京 100048 | | | 孙瑞雯 | 北京市生态环境监测中心, 北京 100048
大气颗粒物监测技术北京市重点实验室, 北京 100048 | | | 董瑞 | 北京市生态环境监测中心, 北京 100048
大气颗粒物监测技术北京市重点实验室, 北京 100048 | | | 王书肖 | 清华大学环境学院, 北京 100084 | | | 郝吉明 | 清华大学环境学院, 北京 100084 | hjm-den@mail.tsinghua.edu.cn |
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| 中文摘要 |
| 利用2018~2020年北京市33个环境评价站和5个区域评价站的空气质量数据，以及气象数据和北京市城区PM2.5组分数据，研究了3年间北京PM2.5的浓度演变、时空变化和重污染发生情况，并对PM2.5组分和气象条件变化进行比较分析.结果发现，3年间北京市ρ（PM2.5）分别为51、42和38 μg ·m-3，2020年的PM2.5相比2017年下降30.9%，但仍超过国际标准8.6%；北京市PM2.5空间分布依旧维持南高北低的特征，但南北差异逐年减小，区域浓度趋于均一化；1~3月PM2.5浓度相对较高，8~9月PM2.5浓度相对较低，采暖季各污染物浓度均显著高于非采暖季，NOx和CO分别偏高58.4%和52.9%，PM2.5偏高27.5%；采暖季和非采暖季PM2.5日变化出现反向特征，采暖季夜间PM2.5明显高于白天，而非采暖季PM2.5峰值出现在中午前后；2018~2020年北京市发生重污染过程16次，重污染天共25 d，主要集中在秋冬季，区域性重污染特征显著；经分析，近年来大气扩散条件有好有差，持续的污染减排仍是PM2.5逐年降低最重要的原因；2020年北京市PM2.5组分中有机物、元素碳和地壳物质浓度较2017年分别下降43.3%、53.2%和51.5%，硝酸盐、硫酸盐和铵盐浓度降幅分别为34.5%、52.2%和43.7%，结果显示北京市PM2.5各主要来源均取得明显控制效果. |
| 英文摘要 |
| Air quality data from 33 environment sites and five regional sites from 2018 to 2020, as well as meteorological data, were used to research PM2.5 variation,spatial and temporal change, diurnal variation, and heavy pollutions in Beijing. The annual average mass concentrations of PM2.5 in Beijing were 51, 42, and 38 μg·m-3, which showed great progress in air quality improvement. However, the PM2.5 concentration in 2020 was still 8.6% above the national limit value despite a 30.9% decline since 2017. The PM2.5 south-north gradient in Beijing remained throughout the three years, but this pattern showed a less significant trend. The highest monthly mean PM2.5 concentrations in Beijing tended to occur in January-March, with the lowest in August-September. NOx, CO, and PM2.5 concentrations were significantly higher in the heating season than in the non-heating season by 58.4%, 52.9%, and 27.5%, respectively. Diurnal variation showed that greater PM2.5 concentrations were observed at nighttime during the heating season and, conversely, at noontime during the non-heating season. Sixteen pollution episodes occurred in Beijing over the last three years, resulting in 25 heavy pollution days distributed in autumn-winter of 2018-2020. The regional heavy pollution characteristics of PM2.5 in Beijing were significant. Through analysis, a continuous pollution reduction was still the most important reason for the yearly decrease in PM2.5. The concentrations of organic matter, elemental carbon, and crustal matter in the PM2.5 in Beijing decreased by 43.3%, 53.2%, and 51.5% since 2017, respectively, and nitrate, sulfate, and ammonium decreased by 34.2%, 52.2%, and 43.7%.The results showed that the control effect of PM2.5 in Beijing was obvious. |
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