上海气溶胶中可溶态营养盐含量及影响因素

为研究上海气溶胶中可溶性营养盐的含量及其变化趋势,在上海华东师范大学采集大气干沉降样品,并分析了2007年6月至2009年3月期间的27个样品中的可溶态营养盐,包括NO3-+NO2-、NH4+、PO43-和SiO32-.以Milli-Q水和盐酸(pH2)连续提取发现,绝大部分硝酸盐/亚硝酸盐(94%)和铵盐(96%)可直接溶解在水中,但硅酸盐(34%)和磷酸盐(50%)在水中溶出的量小于或等于在盐酸中溶出的量.结合大气后向轨迹分析发现,气溶胶的起源和传输途径对营养盐的含量有重要影响.陆源气溶胶颗粒中水溶态NO3-+NO2-和NH4+的质量浓度大于其他类型的气溶胶,但水溶态PO43-和SiO32-在不同类型气溶胶中的浓度差别不大.在降水和来源的双重因素影响下,大气中水溶态营养盐浓度表现为春冬季节高于夏秋季节,具有明显的季节变化特征.

Concentration and impacting factors of soluble nutrients in aerosols,Shanghai

To investigate the concentration and variation of soluble nutrients in the aerosols of Shanghai, 27 aerosol samples were collected from June 2007 to March 2009 in East China Normal University and analyzed for the soluble nutrients, including NO3-+NO2-, NH4+, PO43 -and SiO32-. By continuous leaching with Milli-Q water and hydrochloric acid (pH2), most of the nitrate/nitrite (94%) and ammonium (96%) could be leached in the first step, but the amount of silicate (34%) and phosphate (50%) dissolved in water was equal to or less than that in hydrochloric acid. Combine the nutrients concentration with the back trajectory, the origin and transportation process had significant impacts on aerosol nutrients concentration. The weight concentration for NO3-+NO2- and NH4+ showed the highest value in land-sourced aerosols, but there were not much difference for PO43- and SiO32- in different types of aerosols. The volume-weighted concentration of all nutrients were influenced by both sources and precipitation and showed obvious seasonal characteristics, with higher concentration in Spring and Winter than in Summer and Autumn.