Heterogeneous Chemistry of Surface Exchange

通过采用湿壁流管和鼓泡塔方法以及一种新型的光化学和非均相流管来模拟化合物和真实的样品，研究了穿透雨、树干流和土壤中可溶性和不溶性成分催化的非均相过程，导致NO2的吸收和HONO的释放。吸收速率对pH值的依赖性可以澄清芳香族（即酚），烯烃，脂肪族和羧基结构的吸收过程的贡献。大气相关性，然后可以证明在高湿度的选定气溶胶室实验，通过涂层亲水性纳米粒子，由熔融石英，穿透和其典型的成分，提高气溶胶表面。采用真实的NO2水平，并通过Luminol仪器进行监测。亚硝酸（HONO）痕量的形成可以通过OH自由基的光致光化学间接检测，并且可以通过新型的长光程吸收光度计技术（LOPAP）直接检测。通过离子色谱法、GC-MS、HPLC-UV和FTIR对气溶胶样品进行分析，可以显示植物毒性硝化产物的形成。与次级项目P2至P4密切合作，将有关多相反应的速率常数纳入FLAME-SVAT-CN模拟组的痕量气体模块的大气化学。

The heterogeneous processes, catalysed by soluble and insoluble constituents of throughfall, stemflow and soil, leading to an uptake of NO2 and release of HONO, are investigated by employing the wetted-wall flowtube and bubble column methods and a novel photochemical and heterogeneous flowtube to model compounds and to real samples. The dependence of uptake rates on pH can clarify the contributions of aromatic (i.e. phenolic), olefinic, aliphatic and carboxylic structures to the uptake process. The atmospheric relevance can then be demonstrated by selected aerosol chamber experiments at high humidities, enhancing the aerosol surface by coating hydrophilic nanoparticles, made of fused silica, with throughfall and its typical constituents. Realistic NO2 levels are employed and monitored by a Luminol instrument. Formation of nitrous acid (HONO) traces can be detected indirectly by light-induced photochemistry of OH radicals and it will be detected directly by a novel long-path absorption photometer technique (LOPAP). The formation of phytotoxic, nitrated products can be shown by analysis of aerosol samples employing ion chromatography, GC-MS, HPLC-UV and FTIR. In close cooperation with the sub-projects P2 to P4, the rate constants of the relevant heterogeneous reactions are incorporated into the atmospheric chemistry of the trace gas module of the FLAME-SVAT-CN modelling cluster.