重污染天气应对“绩效分级、差异化管控”措施首次实践效果后评估

Assessment of “Differentiated Response Requirement Based on Performance Grading” Plolicy During Heavy Air Pollution Alert

为提高重污染天气应对的科学性和精准度,2019年7月生态环境部制定重污染天气应对"绩效分级、差异化管控"措施.为应对9月底至10月初的重污染过程,京津冀及周边共68个城市启动重污染预警,该措施得以首次实践.通过时间序列断点回归方法对该措施效果进行评估发现,空气质量改善存在滞后的现象,SO_(2)、NO_(2)和CO这3个气态污染物改善速度较快,对涉及二次生成的O_(3)和PM_(2.5)两个污染物见效速度相对较慢.10月1日恰逢在北京举办庆祝中华人民共和国成立70周年阅兵式,对10月1日当天进行评估,发现与假如不采取措施的情形相比,重污染应急措施使北京市PM_(2.5)、NO_(2)和CO日均浓度显著下降,下降幅度分别为54.1%、62.4%和25.8%.如果不采取重污染应急措施,北京10月1日上午可能出现中重度污染,但实际上空气质量保持在良的水平.区域启动预警的68城市PM_(2.5)、PM_(10)、NO_(2)、SO_(2)和CO都整体改善,部分城市出现了O_(3)不降反升现象.总体看,"绩效分级、差异化管控"作为一项创新性的举措,首次实践取得了较好的空气质量改善效果.

In order to make the heavy air pollution response more scientific and accurate,the Ministry of Ecology and Environment of the People's Republic of China formulated the"differentiated response requirement based on performance grading"policy in July 2019.A total of 68 cities in the Beijing-Tianjin-Hebei region and surrounding areas issued heavy air pollution alerts from late September to early October.This was the first time the policy was put into practice.The regression discontinuity in time design was employed to estimate the effects of the policy on air quality in Beijing and 67 other cities.Here,we showed that the policy basically brought about a short-term,substantial air quality improvement in Beijing and 67 other cities.We found that there was a"lag phenomenon"in which three gaseous pollutants(SO_(2),NO_(2),and CO)achieved improvement relatively quickly;however,O_(3) and PM_(2.5)achieved improvement slowly.A parade to celebrate the 70^(th) anniversary of the founding of the People's Republic of China was coincidently held in Beijing on October 1^(st).Compared with the hypothetical situation in the absence of the heavy air pollution alert,the heavy pollution response measure brought down the concentrations of PM_(2.5),NO_(2),and CO by 54.1%,62.4%,and 25.8%,respectively,in Beijing on October 1^(st).Without the heavy pollution response measures,the air quality rank on the morning of October 1^(st) would have been unhealthy or very unhealthy while the parade was on-going,but in actuality it was moderate.Further analyses of 67 cities found that PM_(2.5),PM_(10),NO_(2),SO_(2),and CO were all improved on October 1^(st),whereas the concentration of O_(3) increased in a portion of the cities.Our study demonstrates that the"differentiated response requirement based on performance grading"policy is effective.