Zheng Zhen-Sen, Dou Jian-Ping, Zhang Guo-Tao, Li Li-Ming, Xu Bo, Yang Wen, Bai Zhi-Peng
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Zibo Ecological Environment Quality Control Service Center, Zibo 255030, China.
Huan Jing Ke Xue. 2023 Apr 8;44(4):1821-1829. doi: 10.13227/j.hjkx.202210204.
To investigate the characteristics and formation mechanism of ozone (O) pollution in an industrial city, an extensive one-month field campaign focusing on O and its precursors (e.g., volatile organic compounds[VOC] and nitrogen oxides[NO]) was conducted in Zibo City, a highly industrializd city in the North China Plain, in June 2021. The 0-D box model incorporating the latest explicit chemical mechanism (MCMv3.3.1) was applied using an observation dataset (e.g., VOC, NO, HONO, and PAN) as model contraints to explore the optimal reduction strategy for O and its precursors. The results showed that ① during high-O episodes, stagnant weather conditions with high temperature and solar radiation as well as low relative humidity were observed, and oxygenated VOCs and alkenes from anthropogenic VOCs contributed the most to the total ozone formation potential and OH reactivity (). ② The in-situ O variation was primarily affected by local photochemical production and export process horizontal to downwind areas or vertical to the upper layer. The reduction in local emissions was essential to alleviate O pollution in this region. ③ During high-O episodes, high concentrations of ·OH (10×10 cm) and HO· (14×10 cm) radical drove and generated a high O production rate (daytime peak value reached 36×10 h). The reaction pathways of HO·+NO and ·OH+NO contributed the most to the in-situ gross O photochemical production (63%) and photochemical destruction (50%), respectively. ④ Compared to those during low-O episodes, the photochemical regimes during high-O episodes were more inclined to be considered as the NO-limited regime. Detailed mechanism modeling based on multiple scenarios further suggested that the synergic emission reduction strategy of NO and VOC, while focusing on NO emission alleviation, would be practical options for controlling local O pollutions. This method could also provide policy-related guidance for the precise O pollution prevention and control in other industrialized Chinese cities.
为研究工业城市臭氧（O）污染特征及形成机制，2021年6月在华北平原高度工业化城市淄博市开展了为期一个月的大规模实地观测活动，重点关注臭氧及其前体物（如挥发性有机化合物[VOC]和氮氧化物[NO]）。利用包含最新显式化学机制（MCMv3.3.1）的零维箱式模型，以观测数据集（如VOC、NO、HONO和PAN）作为模型约束条件，探索臭氧及其前体物的最佳减排策略。结果表明：① 在臭氧高值时段，观测到高温、高太阳辐射、低相对湿度的静稳天气条件，人为源VOCs中的含氧挥发性有机物和烯烃对总臭氧生成潜势和OH反应活性贡献最大。② 本地臭氧变化主要受局地光化学生成以及向顺风区域水平或向上层垂直的输送过程影响。减少本地排放对于缓解该地区臭氧污染至关重要。③ 在臭氧高值时段，高浓度的·OH（10×10⁻⁵ cm⁻³）和HO₂·（14×10⁻⁵ cm⁻³）自由基驱动并产生了较高的臭氧生成速率（白天峰值达到36×10⁻³ ppb h⁻¹）。HO₂· + NO和·OH + NO反应途径分别对局地臭氧光化学总生成（63%）和光化学损耗（50%）贡献最大。④ 与臭氧低值时段相比，臭氧高值时段的光化学状态更倾向于NO限制状态。基于多情景的详细机制模型进一步表明，NO和VOC协同减排策略，在侧重减少NO排放的同时，将是控制本地臭氧污染的可行选择。该方法也可为中国其他工业化城市的臭氧精准防控提供政策相关指导。
