title: Urbanization in China changes the composition and main sources of wet inorganic nitrogen deposition.
abstract: Nowadays, nitrogen (N) deposition has become a growing global concern due to urbanization activities increasing the large amount of reactive N in the atmosphere. However, it remains unclear whether urbanization affects the composition and main sources of N deposition in rapidly urbanizing areas such as in China. One-year measurement of wet inorganic N deposition was conducted using ion-exchange resin (IER) columns in the range of 260 km from urban to rural areas in the Pearl River Delta (PRD) region, south China. An increasing pattern of wet inorganic deposition along the urbanization gradient was observed and it increased in the order: rural (15.26 ± 0.20 kg N ha(-1) year(-1)) < suburban/rural (21.45 ± 3.73 kg N ha(-1) year(-1)) < urban (31.16 ± 0.44 kg N ha(-1) year(-1)) < urban/suburban sites (34.15 ± 5.73 kg N ha(-1) year(-1)). Nitrate N (NO3 (-)-N) accounted for 53.5-79.1 % of total wet inorganic N deposition, indicating a significant negative correlation with distance from the urban core. Based on moss δ(15)N-values the main source of NO3 (-)-N was considered to be emitted from vehicles. Our results demonstrate that urbanization has large impacts on the regional pattern of wet inorganic N deposition. Thus, controlling NOx emission, especially vehicle emission will become an effective strategy for N pollution abatement in China.
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China, lotus-hj@scbg.ac.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Zhu
authors.forename: Frank S
authors.initials: FS
authors.lastname: Gilliam
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Xiankai
authors.initials: X
authors.lastname: Lu
authors.forename: Jiangming
authors.initials: J
authors.lastname: Mo
mesh_terms: D000388:Air / Q000032:analysis* / Q000592:standards; D000393:Air Pollutants / Q000032:analysis*; D064751:Ammonium Compounds / Q000032:analysis; D002681:China; D009566:Nitrates / Q000032:analysis; D017672:Nitrogen Compounds / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D014507:Urbanization; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D009566:Nitrates; D017672:Nitrogen Compounds; D001335:Vehicle Emissions