Liu Pengfei, Xue Chaoyang, Ye Can, Liu Chengtang, Zhang Chenglong, Wang Jinhe, Zhang Yuanyuan, Liu Junfeng, Mu Yujing
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences; Beijing100085, China.
University of Chinese Academy of Sciences; Beijing100049, China.
ACS Environ Au. 2022 Oct 13;3(1):18-23. doi: 10.1021/acsenvironau.2c00048. eCollection 2023 Jan 18.
Recently, deteriorating ozone (O) pollution in China brought the precise diagnosis of O sensitive chemistry to the forefront. As a dominant precursor of OH radicals, atmospheric nitrous acid (HONO) plays an important role in O production. However, its measurement unavailability in many regions especially for second- and third-tier cities may lead to the misjudgment of the O sensitivity regime derived from observation-based models. Here, we systematically assess the potential impact of HONO on diagnosing the sensitivity of O production using a 0-dimension box model based on a comprehensive summer urban field campaign. The results indicated that the default mode (only the NO + OH reaction is included) in the model could underestimate ∼87% of observed HONO levels, leading to an obvious decrease (∼19%) of net O production in the morning, which was in line with the previous studies. The unconstrained HONO in the model was found to significantly push O production toward the VOC-sensitive regime. Additionally, it is unrealistic to change NO but constrain HONO in the model due to the dependence of HONO formation on NO . Assuming that HONO varied proportionally with NO , a stronger NO -sensitive condition could be achieved. Therefore, effective reduction of NO should be given more attention together with VOC emission control for O mitigation.
最近，中国日益恶化的臭氧（O）污染使对O敏感化学的精确诊断成为焦点。作为羟基自由基（OH）的主要前体，大气中的亚硝酸（HONO）在O生成中起着重要作用。然而，在许多地区尤其是二三线城市无法测量HONO，这可能导致基于观测模型得出的O敏感性状况的误判。在此，我们基于一项全面的夏季城市实地考察，使用零维箱式模型系统地评估了HONO对诊断O生成敏感性的潜在影响。结果表明，模型中的默认模式（仅包括NO + OH反应）可能会低估约87%的观测HONO水平，导致早晨净O生成量明显下降（约19%），这与先前的研究一致。模型中未受约束的HONO被发现会显著推动O生成向对挥发性有机化合物（VOC）敏感的状态发展。此外，由于HONO的形成依赖于NO，在模型中改变NO但约束HONO是不现实的。假设HONO与NO成比例变化，则可以实现更强的对NO敏感的条件。因此，为减轻O污染，在控制VOC排放的同时，应更加关注有效减少NO。
