Investigation of source and sink of HONO which is an important radical source in the atmosphere

本文首次提出了流动注射法测定微量HONO的新方法。17秒内的HONO浓度，平均每5分钟测定一次。检测限为15 ppt。利用该方法发现，夜间HONO浓度下降，日出后浓度达到峰值，白天HONO浓度较高。第二年，将该方法改进为连续法，应用于土壤中HONO的测量。在室内实验中，发现铵盐与NO_2相互作用产生HONO。在蒸发过程中，水溶液的组成主要决定了亚硝酸盐、铵、乙酸和甲酸盐的命运，发现碳酸钙结合量对以上溶质的命运起着重要的作用。冻结过程影响HONO的命运，并通过硫化物与过氧化氢的反应建立了冻结反应的理论解。通过两年的研究，可以明确HONO浓度分布的特征。该领域的持续研究将有助于厘清HONO的来源和汇，以及对环境中氮循环的理解。

In the first year, a new determination method for trace amounts of HONO by flow injection analysis has been developed. HONO concentration in 17 seconds-average can be determined every 5 minutes. The detection limit is 15 ppt. With this method, it is found that decrease in HONO concentration in mid-night, peak concentration after sunrise and relatively high level of HONO in daytime. In the second year, this method is improved to continuous method and applied to measure HONO from soil. In laboratory experiment, it is found that an interaction of ammonium salts with NO_2 produces HONO.In the evaporation process, composition in aqueous solution determines mainly fates of nitrite, ammonium, acetate and formate, and it is found that amounts of carbonate combined with calcium plays an important role for the fates of die above solutes. The freezing process affects the fate of HONO, and the theoretical solution of freezing reaction has been build up with a reaction of sulfide with hydrogen peroxide.By researches for two years, the characteristics of HONO concentration profile can be clarified. The continuous research for this field will lead a clarification of HONO source and sink and an understanding of nitrogen cycle in the environment.