浒苔绿潮爆发对海岸大气中新粒子生成和增长的影响

With the burst of green tide (Ulva prolifera) in South Yellow Sea year after year, the ocean emits a large amount of chemically reactive gases into atmosphere, such as dimethyl sulfide, amines, etc. While it is not clear yet how these gases affect the new particle formation and growth, as well as the characteristics of cloud condensation nuclei. Qingdao offshore is an important gathering region of ulva prolifera. In this project, two comparative studies will be conducted to evaluate the effect of green tide on new particle formation events: 1) comparative observation between beach site and in-land background site, 2) comparative study between field observation on the beach and the field chamber experiment. This study will be focused on new particle formation rate, growth rate, maximum grown sizes, CCN efficiency, as well as atmospheric gases and particles during the burst of green tide. This study will calculate the contribution of sulfuric acid, ammonia, nitric acid, methanesulfonic acid (MSA), amines (dimethylamine (DMA), trimethylamine (TMA)), oxalic acid and other organic acids on the growing new particles. By using MSA-、TMA+、DMA+ as the tracers of algae biological activity, the contributions of marine precursors on the formation and growth of new particles will also be quantified during the green tide.

伴随浒苔绿潮在南黄海海域的连年爆发，海洋向大气释放大量的二甲基硫、有机胺等活性气体，但它们如何影响海岸大气中新粒子的生成、增长及云凝结核特征，目前尚不明确。本项目以浒苔的重要聚集地——青岛近海为研究区域，通过两类对比研究认识浒苔绿潮爆发对海岸大气中新粒子生成事件的影响：1）海滩和陆地背景站点的对比观测；2）海滩现场观测与海滩烟雾箱模拟实验的对比研究。本项目将重点研究浒苔绿潮爆发期间新粒子生成速率、增长速率、最大增长粒径、活化为云凝结核效率，以及大气中气体和颗粒物组分的变化；量化硫酸、氨气、硝酸、甲基磺酸（MSA）、有机胺（二甲胺（DMA）、三甲胺（TMA））、乙二酸以及其他有机酸对新粒子增长的影响；以MSA-、TMA+、DMA+为藻类生物活动的示踪物，阐明海洋源气态前体物对新粒子生成和增长的贡献。

伴随浒苔绿潮在南黄海海域的连年爆发，海洋向大气释放大量的二甲基硫、有机胺等活性气体。为研究这些气态前体物如何影响海洋和海岸大气中新粒子的生成、增长及云凝结核特征，本项目在浒苔的重要聚集地——青岛沿海进行外场观测实验，结合在我国近海的船载走航观测历史数据，较为系统的阐明了浒苔绿潮爆发期间大气新粒子生成频率、生成速率、增长速率等特征。研究发现，在夏季沿海地区，生物源有机物对新粒子生成有直接或间接促进作用，人为源有机物对新粒子生成起抑制作用；在受人为源影响的我国陆架海海域，海洋源驱动的新粒子生成事件发生概率很低，而且新粒子生成速率、增长速率也处于较低的范围，乙二酸和三甲胺在新粒子增长中起重要作用；通过开展室外烟雾箱模拟实验，直接测定了浒苔降解产生的气相产物，并且发现高浓度的醛酮类和卤素化合物可有效促进新粒子的生成和增长，增长速率高达28.8~99.2 nm h-1。项目发表学术论文4篇，在国内外学术会议作报告4次，培养研究生2人。研究成果可为理解我国近海海域浒苔绿潮爆发及消亡对大气中新粒子生成和增长的影响提供科学依据。