Xuan Huiying, Lian Chaofan, Ma Pengkun, Lan Linhui, Wang Weigang, Liu Chang, Quan Jiannong, Zhang Shuping, Liu Jun, Li Hao, Chen Tianzeng, Zhang Peng, Wang Yonghong, Chu Biwu, Ma Qingxin, He Hong
State Key Laboratory of Regional Environment and Sustainability, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2025 Aug 26;59(33):17666-17676. doi: 10.1021/acs.est.5c01801. Epub 2025 Aug 12.
Nitrous acid (HONO) plays a significant role in tropospheric air quality as a crucial precursor of hydroxyl radicals (OH). While extensive research has focused on ground-level HONO, the sources and atmospheric implications of high-altitude HONO remain poorly understood. In this study, the Community Multiscale Air Quality (CMAQ) model was employed to explore the vertical distribution of HONO chemistry. The revised model, incorporating five additional HONO sources, effectively reproduced observed HONO concentrations and enhanced the model's performance in simulating ozone and secondary particulate matter. The analysis revealed that the predominant source of HONO near the surface was heterogeneous reactions of NO on the ground surface, with sinks mainly consisting of vertical diffusion, dry deposition and photolysis. In the upper air layer (90-600 m), the primary sources of HONO included the homogeneous reaction of NO with OH, the heterogeneous reaction of NO on the aerosol surface and vertical diffusion, while the main sinks were photolysis and horizontal advection. This study provides valuable insights into the vertical distribution characteristics of HONO chemistry and underscores its critical influence on tropospheric air quality.
亚硝酸（HONO）作为羟基自由基（OH）的关键前体，在对流层空气质量中起着重要作用。尽管大量研究聚焦于地面HONO，但高空HONO的来源及其对大气的影响仍知之甚少。在本研究中，利用社区多尺度空气质量（CMAQ）模型来探究HONO化学的垂直分布。修订后的模型纳入了另外五个HONO源，有效再现了观测到的HONO浓度，并提高了模型在模拟臭氧和二次颗粒物方面的性能。分析表明，地表附近HONO的主要来源是NO在地面的非均相反应，其汇主要包括垂直扩散、干沉降和光解。在高空层（90 - 600米），HONO的主要来源包括NO与OH的均相反应、NO在气溶胶表面的非均相反应以及垂直扩散，而主要汇是光解和水平平流。本研究为HONO化学的垂直分布特征提供了有价值的见解，并强调了其对对流层空气质量的关键影响。
