基于地基观测及源清单的2017-2019年德州市秋冬季大气污染防治效果评估

为评估污染减排措施实施效果，基于地基观测及排放清单数据，运用WRF中尺度气象模型和CAMx空气质量模型，对德州市2017-2019年秋冬季大气污染攻坚实施效果进行了评估.结果表明，2017-2018年秋冬季，德州市ρ（PM_2.5）同比下降31.7%，高于京津冀及周边地区平均水平（25.6%），大气污染攻坚措施成效显著；2018-2019年秋冬季，德州市ρ（PM_2.5）同比增加8.5%，高于京津冀及周边地区平均水平（4.2%），这与不利气象条件及排放量同比减少有关.观测结果显示，2018-2019秋冬季，德州市PM_2.5中无机组分、一次排放示踪物以及SO₂和CO等气态前体物浓度较上一年度呈下降趋势，ρ（SOA）（SOA为二次有机气溶胶）、ρ（NH₄+）同比有大幅增长，增幅分别为53.8%和19.1%，这与大气中VOCs（挥发性有机物，增加46.5%）及大气氧化性（增加6.4%）的增加密切相关，表明德州市复合型大气污染加剧，PM_2.5防控难度加大.综合气象和减排评估结果可知，2017-2018年秋冬季，气象条件（13.4%）和长效措施（9.4%）是德州市PM_2.5改善的两个主要因素；2018-2019年秋冬季，长效措施减排效果较为有限，减排主要来自预警应急（5.0%）和区域减排（5.2%），若仅考虑不利气象条件的影响，将导致同比约19.9%的反弹.因此，持续深入推进长效减排措施，降低污染物排放水平，是德州市实现空气质量改善的根本途径. 

Assessment of Air Pollution Control Effect from Ground-based Observation and Emission Inventory for the Prevention and Control of Air Pollution in Autumn and Winter of Dezhou City from 2017 to 2019

In order to evaluate the effect of emission reduction measures, the effect of air pollution control in autumn and winter from 2017 to 2019 in Dezhou City was evaluated with ground-based observation and emission inventory data, the WRF mesoscale meteorological model and the CAMx air quality model. The results showed that during the winter period from 2017 to 2018, PM_2.5 mass concentration in Dezhou City decreased by 31.7% compared with that of the previous year, which was higher than the average level of Jing-Jin-Ji and its surrounding areas (25.6%), suggesting the extraordinary effect of the prevention and control. During the winter period from 2018 to 2019, PM_2.5 of Dezhou City increased by 8.5% over the last year, which was higher than the average level of Jing-Jin-Ji and its surrounding areas (4.2%). This was related to the unfavorable weather condition and the loose of pollutant emissions. The ground-based observation showed that the concentration of inorganic components, primary emission tracer of PM_2.5 as well as SO₂, CO and other gaseous precursors in Dezhou City all decreased in 2018-2019 while SOA and NH₄⁺ showed substantial increase of 53.8% and 19.1%, respectively, which may be closely related to the increase in volatile organic compounds (increased by 46.5%) and atmospheric oxidation (increased by 6.4%). This result indicated that the air pollution in Dezhou City became more complex and the prevention and control of PM_2.5 will be more difficulties. Based on the comprehensiveanalysis of meteorological and emission reduction assessments, meteorology (13.4%) and long-term emission reduction (9.4%) are two main factors for the improvement in Dezhou City during the winter precaution from 2017 to 2018. During the winter period from 2018 to 2019, the effect of long-term emission reduction was not as important as emergency pre-warning and response (5.0%) and regional emission reduction (5.2%). The unfavorable effects of meteorology conditions would result in approximately 19.9% rebound when other factors were not taken into account. Continuously promoting long-term emission reduction policies and reducing pollutant emission are the fundamental way to achieve air quality improvement.