烟花导致臭氧生成的光化学机理观测与模拟研究

It's well-known that discharge of intensive fireworks can cause serious air pollution. However, so far there is a lack of awareness of fireworks-induced ozone production in China, even though it is the largest county consuming fireworks products. The mechanism of ozone production by fireworks is poorly understood and is still controversial within the comminity. Initiated by the first-hand measurements and findings of ozone production from intensive fireworks displayed in Nanjing during the Chinese Spring Festival, we will carry out further study to investigate the photochemical mechanism from fireworks discharge. Field measurements will be carried out during the future Spring Festivals at the specific location with concentrated fireworks discharge in Nanjing. A chamber will be made to conduct indoor fireworks experiments to characterize the emissions, secondary products and radiation spectrum of the flames from different kind of fireworks displayed under different meteorological conditions and atmospheric environment background. Simulations of photochemical box model and synthesis analysis will be conducted to understand the exact photochemical mechanism for fireworks discharged at night. The improved mechanism will be induced into a regional chemical transport model to further investigate the regional impact of photochemical pollutants from this kind short-term but with high-intensity and large-scale human activities.

本项目从前期野外观测试验所获得的关于春节大规模烟花燃放产生臭氧的第一手观测事实出发，针对目前国际上尚无定论的烟花燃放导致臭氧生成的光化学机理开展深入研究。项目计划有针对性地选择南京市春节期间烟花燃放最为集中的地点开展两期短期强化观测试验，同时组织实施室内烟花燃放模拟，测定不同气象条件、大气环境背景下不同种类烟花燃放的排放、火焰光谱特性和二次产物，据此通过光化学箱体模式数值模拟和集成分析，明晰夜间烟花燃放导致臭氧生成的确切化学机制；并在此基础上，将相应机制引入区域空气质量模型，研究这种短期、高强度、大规模人类活动对区域光化学污染的影响。

本项目拟从2001年印度科学家Attri等人发表在Nature上的论文以及2011年春节期间南京观测到的高浓度臭氧出发，研究烟花燃放期间“观测到的”臭氧生成的成因，揭示烟花燃放对于大气化学的影响。项目在实施过程中，按照计划分析了南京、香港、北京、上海等地春节期间臭氧及大气成分观测资料，在南京及其周边地区组织了两期针对烟花燃放的强化观测试验，同时设计实验室流动管试验，测试烟花燃放的直接排放及其光谱特征。相关工作发现，在我国若干超大城市春节高强度烟花燃放期间，并没有臭氧生成的信号，而强化试验的对比测量发现，原先Nature论文所报道的“高浓度臭氧”事件并非其所揭示的“类平流层机制”，而是由于测量过程中高浓度颗粒物以及有机物对于紫外法测量臭氧仪器的干扰。同时，通过大气化学传输模式的模拟，发现南京2011年春节期间所观测到的高浓度臭氧并非先前所猜测的“可能是烟花燃放的影响”，而是由于独特的气象条件加上机动车排放等人为源的显著减少，通过非线性的光化学过程反而导致的臭氧增加。围绕项目相关的研究内容所开展的多项观测试验和模拟，项目组先后发表5篇SCI论文，并有多篇论文正在准备中。项目先后培养7名博士、硕士研究生，项目负责人也获得多项国内外重要科研奖项。