青岛近海不同污染过程下大气颗粒态氮磷浓度分布特征

Concentrations and Patterns of Atmospheric Particulate Nitrogen and Phosphorus During Different Weather Conditions in Qingdao Coastal Region

2018年3月~2019年10月在青岛近海连续采集了大气气溶胶样品,测定出样品中溶解无机氮(DIN)、溶解无机磷(DIP)、溶解态总氮(DTN)、溶解态总磷(DTP)、总氮(TN)和总磷(TP)的浓度分别为(7.13±6.59)μg·m^(-3)、(17.42±9.88)ng·m^(-3)、(8.34±7.03)μg·m^(-3)、(25.59±13.67) ng·m^(-3)、(10.68±10.59)μg·m^(-3)和(76.34±51.79) ng·m^(-3).结果表明,受排放源强度、气团来源和气象条件等因素影响,采样期间气溶胶中不同形态氮磷浓度变化范围较大,DIN、DTN和TN呈现秋季浓度最高,春季和冬季次之,夏季浓度最低的季节变化特征;DIP、DTP浓度与氮组分具有相似的季节变化,表现为秋季高,夏季低,而TP浓度在春季最高,夏季最低.霾天气溶胶中不同形态氮磷浓度较晴天对照天均显著增加,DIN、DTN和TN较对照天分别提高了4.3、3.8和4.5倍,而DIP、DTP和TP较对照天分别提高了1.9、1.9和1.2倍,但不同时期霾天样品的氮组分浓度增长幅度相差较大,其中采暖期与非采暖期霾天气溶胶中DIN/DTN的值分别为(92.65±4.09)%和(80.52±8.42)%,较对照天分别提高了8.87%和4.83%;而采暖期与非采暖期霾天气溶胶中DTN/TN值分别为(73.41±12.18)%和(80.36±4.72)%,较对照天分别降低了13.35%和5.92%.霾天气溶胶中DIP占DTP的比重较对照天仅提高了1.47%,但变化较为复杂,随霾天不同而有较大差异;受气团来源、相对湿度和大气酸化过程等因素影响,气溶胶中DTP/TP的值较对照天提高了10.58%.受沙尘事件影响的气溶胶中DIN、DTN和TN的浓度较对照天分别提高了2.5、2.6和2.6倍,DIP、DTP和TP的浓度较对照天分别提高了4.0、2.8和7.2倍.

Total suspended particulate (TSP) samples were continuously collected in the Qingdao coastal region from March 2018 to October 2019.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 samples were (7.13±6.59)μg·m^(-3),(17.42±9.88) ng·m^(-3),(8.34±7.03)μg·m^(-3),(25.59±13.67) ng·m^(-3),(10.68±10.59)μg·m^(-3),and(76.34±51.79) ng·m^(-3),respectively.The results showed that the concentrations of different nitrogen and phosphorus species in aerosols varied significantly during the sampling period due to the influence of emission intensity,air mass source,and meteorological conditions.The concentrations of DIN,DTN,and TN were the highest in autumn followed by spring,winter,and summer,showing similar seasonal variations.However,TP showed the highest concentration in spring and the lowest in summer.The concentrations of DIN,DTN,and TN on haze days were 4.3,3.8,and 4.5 times higher than on non-haze reference days,respectively,and DIP,DTP,and TP concentrations were 1.9,1.9,and 1.2 times higher,respectively.During the heating period,the DIN/DTN ratio on haze days was (92.65±4.09)%,which was 8.87%higher than on non-haze days.During the non-heating period,the DIN/DTN ratio was(80.52±8.42)%,which was 4.83%higher than the reference days.However,the average DTN/TN ratio on haze days was significantly lower than on non-haze days;the average DTN/TN ratio on haze days was (73.41±12.18)%and (80.36±4.72)%during the heating and non-heating period,respectively,and were 13.35%and 5.92%lower,respectively,on non-haze days.The proportion of DIP to DTP on hazy days increased by only 1.47%relative to non-haze days,while the DIP/DTP ratio varied between hazy days.Due to the influence air mass sources,relative humidity,and atmospheric acidification process,the DTP/TP ratio on haze days increased by 10.58%relative to non-haze days.The concentrations of DIN,DTN,and TN in aerosols affected by dust events were 2.5,2.6,and 2.6 times higher than on non-dust days,while DIP,DTP,and TP were 4.0,2.8,and 7.2 times higher,respectively.