Qin Ze, Liu Yanhui, Bai Wenyu, Zhang Gen, Xu Bo, Liu Yingying, Geng Chunmei, Zhang Nan, Zhao Xueyan, Yang Wen
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Environ Pollut. 2025 Mar 1;368:125674. doi: 10.1016/j.envpol.2025.125674. Epub 2025 Jan 10.
As a vital precursor of hydroxyl radicals (OH), atmospheric nitrous acid (HONO) plays a significant role in tropospheric chemistry and the production of secondary pollutants. However, knowledge of its sources remains insufficient. To comprehensively investigate the HONO chemistry in polluted cities and alleviate O pollution, based on a comprehensive HONO-related field campaign in Zibo City, on the North China Plain, the parameterized formulas of additional HONO sources were validated in a box model (based on the default MCMv3.3.1) and the resulting chemical impact of HONO was determined. The results showed that the updated mechanism well reproduced the diurnal profile of observed HONO, and budget analysis revealed the predominant role of the NO photo-enhanced heterogeneous reaction on the ground surface in HONO formation, with contributions of about 70% during both high-O episodes and clean days. Underestimations of 32.1% in net O production rate and 28.5% in HO concentrations were simulated by the default mechanism when HONO was not constrained, while the adoption of the updated mechanism reduced these underestimations to 5.3% and 5.4%, respectively. Additionally, sensitivity tests of NO emission changes showed that the urban O photochemical regime was more inclined to NO-limited after considering variations in HONO concentrations caused by changes in NO concentrations. These results can contribute to more precise O pollution control strategies in urban areas, especially in regions lacking HONO observations.
作为羟基自由基（OH）的重要前体，大气中的亚硝酸（HONO）在对流层化学和二次污染物的产生中起着重要作用。然而，其来源的相关知识仍然不足。为了全面研究污染城市中的HONO化学并减轻O污染，基于在华北平原淄博市开展的一次与HONO相关的综合实地考察，在一个箱式模型（基于默认的MCMv3.3.1）中验证了额外HONO来源的参数化公式，并确定了HONO产生的化学影响。结果表明，更新后的机制很好地再现了观测到的HONO的日变化曲线，预算分析揭示了地表NO光增强非均相反应在HONO形成中的主导作用，在高O事件和清洁日期间的贡献均约为70%。当不考虑HONO的影响时，默认机制模拟的净O产生率低估了32.1%，HO浓度低估了28.5%，而采用更新后的机制分别将这些低估降低到了5.3%和5.4%。此外，NO排放变化的敏感性测试表明，在考虑NO浓度变化引起的HONO浓度变化后，城市O光化学状态更倾向于NO限制型。这些结果有助于在城市地区，特别是在缺乏HONO观测的地区制定更精确的O污染控制策略。
