Yu Xiao-Hong, Yang Ai-Qin, Chen Ling, Wang Yan, Zhu Ling-Yun, Wang Wen-Ya, Wang Xiao-Lan, Yan Shi-Ming, Chen Er-Ping
Monitoring and Assessment Center for Greenhouse Gases and Carbon Neutrality of China Meteorological Administration, Shanxi Branch, Shanxi Institute of Meteorological Science, Taiyuan 030002, China.
Wutaishan Cloud Physics Field Experiment Base, China Meteorological Administration, Taiyuan 030002, China.
Huan Jing Ke Xue. 2024 Aug 8;45(8):4432-4439. doi: 10.13227/j.hjkx.202311244.
Satellite-based formaldehyde（HCHO）columns and tropospheric nitrogen dioxide columns were observed using the Ozone Monitoring Instrument（OMI），and groundbased observations of ozone（O）for May-August from 2013 to 2022 were connected to calculate the threshold values of the HCHO to NO ratio（FNR）in Shanxi Province. Then，the spatiotemporal distributions and variations in summertime ozone photochemical production regimes were analyzed. The results showed that：① The volatile organic compound（VOC） -sensitive regime area（FNR < 2.3）was obviously reduced，while the VOCs-NO transitional regime（FNR between 2.3-4.1）area increased in the early years and then decreased， and NO x -sensitive regime area expanded significantly in summer from 2013 to 2022 over Shanxi Province. ② The increased summertime FNR during 2013 to 2019 was associated with the co-effect of increased HCHO columns and decreased tropospheric NO columns. The Shanxi Province was generally under an NO regime since 2016，which reflected the remarkable effect of NO x emission reductions；however，there was a shift from a VOC-sensitive regime to a VOCs-NO transitional regime，in which O pollution aggravation was widespread under the background of decreased NO emissions. The decrease in O concentration during 2020 to 2022 followed the synergistical declines in HCHO columns and tropospheric NO columns. ③ The O weekend effects were reversed in Linfen and Yuncheng but were persistent in the other nine cities. Satellite-based weekend HCHO and NO levels were higher than those on weekdays in some cities of Shanxi Province，indicating that the O weekend effect was not only dependent on the changes of precursors emissions but was also closely related to O photochemical production sensitivity. The results indicated the necessity of simultaneous controls in NO emissions and VOCs emissions for ozone abatement plans over Shanxi Province. In addition，Taiyuan，Yangquan，Yuncheng，and Jincheng should continue to promote reduction in NO emissions.
利用臭氧监测仪器（OMI）观测了基于卫星的甲醛（HCHO）柱浓度和对流层二氧化氮柱浓度，并结合2013年至2022年5月至8月的地面臭氧（O₃）观测数据，计算了山西省HCHO与NO比值（FNR）的阈值。然后，分析了夏季臭氧光化学产生机制的时空分布和变化。结果表明：① 挥发性有机化合物（VOC）敏感机制区域（FNR < 2.3）明显减少，而VOCs-NO过渡机制区域（FNR在2.3 - 4.1之间）面积在早期增加，随后减少，并且在2013年至2022年夏季，山西省的NOₓ敏感机制区域显著扩大。② 2013年至2019年夏季FNR的增加与HCHO柱浓度增加和对流层NO柱浓度降低的共同作用有关。自2016年以来，山西省总体处于NO主导的机制下，这反映了NOₓ减排的显著效果；然而，存在从VOC敏感机制向VOCs-NO过渡机制的转变，在NO排放减少的背景下，O₃污染加剧的情况普遍存在。2020年至2022年期间O₃浓度的下降伴随着HCHO柱浓度和对流层NO柱浓度的协同下降。③ 临汾和运城的O₃周末效应发生了反转，但在其他九个城市持续存在。山西省部分城市基于卫星的周末HCHO和NO水平高于工作日，表明O₃周末效应不仅取决于前体物排放的变化，还与O₃光化学产生敏感性密切相关。结果表明，山西省臭氧减排计划需要同时控制NO排放和VOCs排放。此外，太原、阳泉、运城和晋城应继续推进NO排放的减少。
