宝鸡市大气PM_(10)中水溶性物质的组成及特征研究

2008年冬、春季在宝鸡市4个不同功能区采集PM10样品,探讨了PM10中水溶性物质的化学组成、时空分布特征以及来源。结果表明,冬、春季PM10的平均质量浓度分别为(402±100)、(410±160)μg/m3,无明显季节差异,冬季以交通干道区的PM10浓度为最高,而春季则以商贸区的PM10浓度为最高;冬、春季PM10中水溶性有机碳(WSOC)浓度最高值均出现在商贸区,最低值则分别出现在背景点和交通干道区,水溶性无机碳(WSIC)浓度最高值分别出现在交通干道区和商贸区,最低值均出现在背景点;冬、春季PM10中所含大多数无机离子浓度不存在显著空间差异,但不同功能区PM10中无机离子所占质量分数差异较明显;冬、春季PM10中的水溶性物质质量浓度分别为207、151μg/m3,在PM10中所占质量分数分别为51%和40%,其中,冬、春季水溶性物质浓度最高的分别为居民区和商贸区;冬季PM10中WSOC浓度与SO24-、NO3-浓度有较好的相关性,说明冬季PM10中WSOC的主要组分为二次有机气溶胶,而春季PM10中WSOC浓度与SO42-、NO3-浓度的相关性相对较差,这是由于一次有机气溶胶对WSOC的贡献率较冬季显著增大;宝鸡市与北京市大气PM10浓度、PM10中的SO42-、NO3-、NH4+浓度最为接近;广州市大气PM10中的SO42-所占质量分数(14%)要高于北方城市(宝鸡市和北京市均为9%)。

Component and characteristics of water-soluble species in PM_(10) aerosol of Baoji

Several PM_(10) samples were collected at four functional areas of Baoji during winter and spring of 2008 to investigate the component, distribution characteristic and origin of water-soluble species in PM_(10). The results showed that the average PM_(10) concentrations in winter and spring were(402±100) and(410±160) μg/m~3 respectively, with no significant seasonal difference. The highest PM_(10) concentration was found at the traffic center in winter and downtown sites in spring. The amount of water-soluble organic carbon (WSOC) was highest in PM_(10) collected in downtown, and the lowest WSOC appeared in PM_(10) at background site and traffic center. For water-soluble inorganic carbon (WSIC), the highest WSIC was found at traffic center and downtown, and the lowest WSIC was found at background site. The space distribution of inorganic ions was also investigated. The concentrations of water soluble matter in winter and spring PM_(10) were 207 and 151 μg/m~3 , which account for 51 % and 40% of total PM_(10) , and residential area and downtown owned the highest amount of water soluble matter. In PM_(10) collected at winter, the concentration of WSOC was well correlated with SO_4~(2-) and NO_3~- , suggested that secondary organic aerosol was the main component of WSOC. The contribution of POA for WSOC was increased in spring for the relative poor correlation between WSOC and SO_4~(2-) and NO_3~-.