SO42-是PM10中的重要组成成分，其形成过程受到多个因子的影响。本文利用高频的自动在线分析系统连续观测了采暖季北京大气中的SO42-与硫氧化率，并探讨了它们与气态前体物、氧化剂、气象因子等的关系。结果表明在采暖季SO42－仍然是PM10中的重要组成部分，并且与SO2显著线性相关，燃煤仍然是采暖季的主要污染来源；非污染期的SO42-来源于远距离输送的老化气团，硫氧化率高，O3浓度的增加对SO2的转化有促进作用；污染期SO42-来源于局地的一次排放，硫氧化率低；整个观测期内风速对颗粒物中SO42-浓度影响较大，温度、相对湿度与SO42-和硫氧化率无明显相关关系。

Sulfate is a major component of PM10 in atmosphere and its concentration is affected by many factors. In this article, sulfate concentration and sulfur oxidation ratio in heating season were measured with on-line systems, and the relationships between sulfur oxidation ratio and influencing factors were discussed.
The results showed that the most abundant component of PM10 was sulfate and there was a significant correlation between sulfate and SO2 during heating season in Beijing. Coal burning was still the primary pollution source in heating season. During non-pollution period, SO42- was mainly from aged air mass with high sulfur oxidation ratio which was promoted by O3 during long range transportation. During pollution period, SO42- was mainly from original source with lower sulfur oxidation ratio which had no obvious correlation with O3. Execpt wind speed, there were no significant correlations bwteen meterological facotrs and sulfate and between meteorological factors and sulfur oxidation ratio during observation.