Zhen Shaosong, Luo Min, Shao Yang, Xu Diandou, Ma Lingling
Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.
School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2025 May 25;15(1):18174. doi: 10.1038/s41598-025-01179-9.
Nitrate (NO) is a crucial component of atmospheric pollutants, and understanding its sources and formation mechanisms holds significant importance for air pollution control. In this study, stable isotope techniques and Bayesian Mixing Models (Mix SIAR) were applied to analyze the primary sources and formation processes of NO in PM and PM in Beijing in 2022. The results indicate that the contribution of vehicle exhaust, coal combustion, biomass burning, and soil emissions to NO in PM were 33.9%, 20.5%, 29.8%, and 15.9%, respectively, while for PM, the contributions were 30.6%, 21.6%, 29.9%, and 17.9% respectively. An analysis of δO-NO values indicated that the contribution of NO hydrolysis to NO in PM and PM over the year was 64.0% and 75.6%, respectively, highlighting its predominant role in nitrate formation. Nevertheless, the gas-phase reaction of NO with ·OH radicals was notably more pronounced in summer. Compared to PM, the gas-phase reaction of NO with ·OH radicals contributes more to NO in PM. These results offer a vital foundation for further research into the sources and formation mechanisms of atmospheric NO and provide scientific support for measures to prevent and control air pollution.
硝酸盐（NO）是大气污染物的重要组成部分，了解其来源和形成机制对空气污染控制具有重要意义。本研究应用稳定同位素技术和贝叶斯混合模型（Mix SIAR）分析了2022年北京市颗粒物（PM）中NO以及PM的主要来源和形成过程。结果表明，机动车尾气、煤炭燃烧、生物质燃烧和土壤排放对PM中NO的贡献分别为33.9%、20.5%、29.8%和15.9%，而对PM而言，其贡献分别为30.6%、21.6%、29.9%和17.9%。对δO-NO值的分析表明，全年NO水解对PM和PM中NO的贡献分别为64.0%和75.6%，突出了其在硝酸盐形成中的主要作用。然而，NO与·OH自由基的气相反应在夏季更为明显。与PM相比，NO与·OH自由基的气相反应对PM中NO的贡献更大。这些结果为进一步研究大气NO的来源和形成机制提供了重要基础，并为空气污染防治措施提供了科学支持。
