青岛近海及黄渤海大气气溶胶中不同形态氮磷质量浓度及组成特征

于2016年6~7月采集了青岛近岸以及黄渤海大气气溶胶样品,并于8月6~15日连续采集了青岛近岸气溶胶昼夜样品,分别测定了不同形态的氮磷(溶解无机氮、溶解无机磷、溶解态总氮、溶解态总磷、总氮和总磷)质量浓度,并分析了气溶胶中这些不同形态氮磷的组成特征.结果表明,青岛近岸大气气溶胶中不同形态氮磷的浓度明显高于同时期黄渤海气溶胶中氮磷浓度.青岛近岸气溶胶总氮中溶解态占比为56%,溶解态与不溶态差别不大;黄渤海气溶胶总氮中溶解态为主要部分,所占比例达72%.青岛以及黄渤海气溶胶中,无机氮是溶解态总氮的主要贡献者,分别占溶解总氮的67%和75%.青岛以及黄渤海气溶胶总磷中,溶解态与不溶态磷的贡献相近,溶解态分别占总磷的49%和58%;气溶胶溶解总磷中无机磷的贡献略高于有机磷,青岛以及黄渤海占比分别为56%和59%.气团来源对青岛以及黄渤海气溶胶中不同形态氮磷的浓度和组成特征有一定程度的影响,南方气团来源气溶胶中溶解无机氮(DIN)、溶解有机氮(DON)、总氮(TN)、溶解无机磷(DIP)和溶解有机磷(DOP)的浓度均高于北方和海上气团来源.青岛近岸气溶胶中溶解有机氮浓度昼夜差别不大,而溶解无机氮和总氮浓度则白天相对较高.白天和夜间气溶胶总氮中溶解态氮占主要部分,所占比例达到79%,且无昼夜变化;无机氮是溶解总氮的主要贡献者,且晚上无机氮所占比例(61%)较白天(70%)略有降低.青岛近岸气溶胶中的溶解无机磷和有机磷昼夜浓度差别不大,而总磷浓度则白天明显高于晚上.昼夜气溶胶样品中不溶态磷是总磷的主要组成部分,占比分别为83%、62%,夜间气溶胶中溶解态磷的贡献远高于白天;不论昼夜,无机磷均是溶解总磷的主要部分,所占比例在71%~77%.

Concentrations and Compositions of Different Forms of Nitrogen and Phosphorus in Atmospheric Aerosols in the Qingdao Coastal Region and over the Yellow and Bohai Sea

The total suspended particulate (TSP) samples were collected in the Qingdao coastal region and over the Yellow and Bohai Sea from June to July in 2016. The diurnal and nightly TSP samples were also continuously collected in the Qingdao coastal region from August 6 to 15. The concentrations of dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), total nitrogen (TN), and total phosphorus (TP) in the TSP samples were analyzed. Results showed that the concentrations of different forms of nitrogen and phosphorus in Qingdao were higher than those over the Yellow and Bohai Sea during the same sampling period. The contribution of dissolved N was similar to that of insoluble N to TN in Qingdao, with the ratio of DTN to TN of 56%. However the DTN was the dominant contributor of TN over the Yellow and Bohai Sea, accounting for 72% of TN on average. The inorganic nitrogen was the dominant species of DTN in Qingdao and over the Yellow and Bohai Sea (YBS), accounting for 67% and 75% of DTN, respectively. The contribution of dissolved P to TP was similar to that of insoluble P to TP in Qingdao and over the Yellow and Bohai Sea, and the DTP accounted for 49% and 58% of TP in Qingdao and over YBS, respectively. The ratio of IP to DTP was slightly higher than that of OP, with values of 56% and 59% in Qingdao and over the YBS, respectively. The origin of the air mass affected the concentrations and compositions of nitrogen and phosphorus in the aerosols. The concentrations of DIN, dissolved organic nitrogen (DON), TN, DIP, and dissolved organic phosphorus (DOP) in the aerosols from southern air mass were higher than those from northern and marine air masses. The concentration of DON in the diurnal aerosol samples was similar to that in the nightly samples; however, the concentrations of DIN and TN were higher in the diurnal aerosols than those in the nightly aerosols. The DTN was the dominant species of TN in the diurnal and nightly aerosol samples, accounting for 79% of TN on average. Inorganic nitrogen was the dominant species of DTN in the diurnal and nightly aerosols. The ratio of DIN to DTN decreased from 70% in diurnal samples to 61% in nightly samples. The concentrations of DIP were close to that of DOP in the diurnal and nightly aerosols; however, the concentrations of TP were higher in the diurnal aerosols than in the nightly ones. The insoluble P was the dominant form of TP in the aerosols, accounting for 83% and 62% of TP during the day and night, respectively. The contribution of DTP to TP in the nightly aerosols samples was much higher than that in the diurnal aerosols. For both day and night samples, inorganic phosphorus was the dominant species of DTP in aerosols, with a ratio of 71%-77%.