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

在第一年，我们发展了流动注射分析测定痕量HONO的新方法。17秒内的HONO浓度-平均值可以每5分钟测定一次。检测限为15 ppt。结果表明，HONO浓度在午夜下降，在日出后达到峰值，白天浓度相对较高。第二年，将该方法改进为连续法，并应用于土壤中HONO的测定。在实验室条件下，铵盐与NO_2的相互作用产生HONO，在蒸发过程中，水溶液的组成主要决定了亚硝酸盐、铵、乙酸盐和甲酸盐的去向，并且发现碳酸盐与钙结合的量对上述溶质的去向起着重要的作用。冻结过程影响HONO的归宿，以硫化物与过氧化氢反应为例，建立了冻结反应的理论解，通过两年的研究，阐明了HONO浓度分布的特征。这一领域的持续研究将有助于阐明HONO的源和汇，并有助于理解氮在环境中的循环。

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.