Ambient concentration and dry deposition of major inorganic nitrogen species at two urban sites in Sichuan Basin, China
Ambient concentration and dry deposition of major inorganic nitrogen species at two urban sites in Sichuan Basin, China
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中国四川盆地两个城市站点主要无机氮的环境浓度和干沉降
DOI：
10.1016/j.envpol.2016.10.016
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发表时间：
2016
影响因子：
8.9
通讯作者：
Fu Chuan
中科院分区：
文献类型：
--
作者：
Wang Huanbo;Yang Fumo;Shi Guangming;Tian Mi;Zhang Leiming;Zhang Liuyi;Fu Chuan
为评估四川盆地敏感生态系统中主要无机氮形态的污染水平及其大气沉降输入，于2014年7月至2015年4月在两个城市采样点采集了4个为期1个月的氧化态（NOy = NO2，HNO 3，NO3−）和还原态（NHx= NH3，NH 4+）氮形态的环境浓度。成都和万州的NOy年平均浓度分别为20.3和13.5 μg N m− 3，NHx年平均浓度分别为16.9和13.6 μg N m−3。后向轨迹聚类分析表明，成都市NO_2和NH_3的高浓度主要是由本地排放造成的，而万州市的高浓度则是本地排放和污染物远距离输送共同作用的结果。NO2对NOy的贡献最大，其次是NO3−和HNO 3，分别占成都NOy的87.5%、10.5%和2.0%，万州NOy的贡献率分别为91.4%、6.9%和1.7%。NH3是NHx的主要贡献者，在成都和万州分别占65.6%和72.2%。干沉降通量估计使用推断方法与测量的环境浓度和模拟的干沉降速度。成都和万州的无机氮干沉降通量分别为21.4和8.5 kg N ha-1 yr-1，分别占44.3%和41.4%。NO_2和NH_3分别贡献了NO_2和NH_4干沉降的80%左右。仅在万州收集了湿沉降，其中NO3−和NH 4+的年湿沉降量分别为4.5和15.7 kg N ha− 1 yr −1。万州的湿沉降加干沉降总量为28.7 kg N ha-1 yr-1，其中72.2%来自还原氮。因此，控制来自农业、交通、垃圾容器和污水系统的NH3排放将有效减少四川盆地地区的总氮沉降。
To assess pollution levels of major inorganic nitrogen species and their atmospheric deposition input to sensitive ecosystems in Sichuan Basin, southwest China, ambient concentrations of oxidized (NOy∼ NO2, HNO3, NO3−) and reduced (NHx= NH3, NH4+) nitrogen species were collected at two urban sites during four one-month periods, each in a different season from July 2014 to April 2015. Estimated annual mean concentration of NOywas 20.3 and 13.5 μg N m−3in Chengdu and Wanzhou, respectively, and NHxwas 16.9 and 13.6 μg N m−3, respectively. Back trajectory cluster analysis indicated that high levels of NOyand NHxin Chengdu were mainly caused by local emissions while those in Wanzhou were caused by both the local emissions and long-range transport of pollutants. On annual basis, NO2contributed the most to NOy, followed by NO3−and HNO3, accounting for 87.5%, 10.5% and 2.0%, respectively, of NOyin Chengdu, and 91.4%, 6.9% and 1.7%, respectively, in Wanzhou. NH3was the predominant contributor to NHx, contributing 65.6% and 72.2% in Chengdu and Wanzhou, respectively. Dry deposition fluxes were estimated using the inferential method with measured ambient concentrations and modelled dry deposition velocities. The total inorganic nitrogen dry deposition flux was estimated to be 21.4 and 8.5 kg N ha−1yr−1, with 44.3% and 41.4% from NOyin Chengdu and Wanzhou, respectively. NO2and NH3each contributed about 80% of NOyand NHxdry deposition, respectively. Wet deposition was only collected in Wanzhou, where the annual wet deposition of NO3−and NH4+was 4.5 and 15.7 kg N ha−1yr−1, respectively. The total wet plus dry deposition was 28.7 kg N ha−1yr−1in Wanzhou with 72.2% from reduced nitrogen. Therefore, controlling NH3emissions from agricultural, traffic, waste containers and sewage system sources would be effective to reduce the total nitrogen deposition in the Sichuan Basin area.