中文摘要：

依据1989-2003年监测数据，分析了西安市大气硫酸盐化速率的时空变化。结果发现：①硫酸盐化速率年内变化呈“山谷”型，冬季最大，春季次之，夏季和秋季最低；②以2001年为界，硫酸盐化速率的年际变化呈“先升后降”的趋势；③硫酸盐化速率的空间分布，在2001年之前是工业区≥商业区≥居住区，2001年之后转化为商业区≥居住区≥工业区；④14a同步监测数据的相关分析发现，硫酸盐化速率的年际变化与SO2和TSP具有较强的相关性，反映出其形成的途径主要是在颗粒物表面的催化氧化。

英文摘要：

Being a famous historical and cultural city in the world, Xi＇an City is an important base of science, technology, education, commerce and trade, finance and modern processing in northwestern China, and is also a famous international tourist city. Air pollution in Xi＇ an City directly affects the development of international tourism, people＇ s health and increase of the synthetic urban competition strength. Xi＇ an City was one of the ten cities with the most serious pollution in the world in the 1990s. Air was mainly polluted by TSP and SO2, and people＇s health and social and economic development were seriously affected. In this paper, the spatiotemporal change of air sulphation speed in Xi＇an City during the period of 1989- 2003 is analyzed. The results are follows： （1） The curve of the annual sulphation speed is valley-shaped, the maximum value occurs in winter, then that in spring, and the minimum value occurs in summer and autumn; （2） The annual change of sulphation speed was increased before 2001, and then gradually decreased; （3） Spatially, the air sulphation speed was the highest in the industrial areas before 2001, then in the commercial areas, and it was the lowest in the residential areas; after 2001 the highest values occurs in the commercial areas, then in the residential areas, and the lowest value occurs in the industrial areas; （4） After carrying out the correlation analysis on the 14-year measured data, it is found that there is a strong correlation between the sulphation speed and the SO2 and TSP, which is mainly caused by the catalytic oxidation on the surface of TSP in Xi＇an City.