1College of Resources and Environmental Sciences, Key Laboratory of
Plant-Soil Interactions of MOE, Beijing Key Laboratory of Cropland Pollution
Control and Remediation, China Agricultural University, Beijing 100193,
China
2State Key Laboratory of Urban and Regional Ecology, Research Center
for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road
18, Haidian District, Beijing 100085, China
3Jiangsu Provincial Key Laboratory of Geographic Information Science
and Technology, International Institute for Earth System Science, Nanjing
University, Nanjing 210023, China
4State Key Laboratory of Environmental Criteria and Risk Assessment,
Chinese Research Academy of Environmental Sciences, Beijing 100012, China
5Laboratory for Climate and Ocean-Atmosphere Sciences, Department of
Atmospheric and Oceanic Sciences, School of Physics, Peking University,
Beijing 100871, China
6State Key Laboratory of Atmospheric Boundary Layer Physics and
Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese
Academy of Sciences, Beijing 100029, China
7School of Agriculture and Food Sciences, The University of Melbourne, Victoria,
3010, Australia
8Department of Land Management, Zhejiang University, Hangzhou 310058,
China
9Arizona Department of Environmental Quality, Phoenix, AZ 85007, USA
10Institute of Subtropical Agriculture, Chinese Academy of Sciences,
Changsha 410125, China
11Institute of Surface-Earth System Science, Tianjin University,
Tianjin 300072, China
12Institute of Plant Nutrition, Resources and Environmental Sciences,
Henan Academy of Agricultural Sciences, Henan Key Laboratory of Agricultural
Eco-environment, Zhengzhou 450002, China
13State Key Laboratory of Pollution Control & Resource Reuse, School
of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu
210023, China
14Department of Atmospheric Science, Colorado State University, Fort
Collins, Colorado, 80523 USA
1College of Resources and Environmental Sciences, Key Laboratory of
Plant-Soil Interactions of MOE, Beijing Key Laboratory of Cropland Pollution
Control and Remediation, China Agricultural University, Beijing 100193,
China
2State Key Laboratory of Urban and Regional Ecology, Research Center
for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road
18, Haidian District, Beijing 100085, China
3Jiangsu Provincial Key Laboratory of Geographic Information Science
and Technology, International Institute for Earth System Science, Nanjing
University, Nanjing 210023, China
4State Key Laboratory of Environmental Criteria and Risk Assessment,
Chinese Research Academy of Environmental Sciences, Beijing 100012, China
5Laboratory for Climate and Ocean-Atmosphere Sciences, Department of
Atmospheric and Oceanic Sciences, School of Physics, Peking University,
Beijing 100871, China
6State Key Laboratory of Atmospheric Boundary Layer Physics and
Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese
Academy of Sciences, Beijing 100029, China
7School of Agriculture and Food Sciences, The University of Melbourne, Victoria,
3010, Australia
8Department of Land Management, Zhejiang University, Hangzhou 310058,
China
9Arizona Department of Environmental Quality, Phoenix, AZ 85007, USA
10Institute of Subtropical Agriculture, Chinese Academy of Sciences,
Changsha 410125, China
11Institute of Surface-Earth System Science, Tianjin University,
Tianjin 300072, China
12Institute of Plant Nutrition, Resources and Environmental Sciences,
Henan Academy of Agricultural Sciences, Henan Key Laboratory of Agricultural
Eco-environment, Zhengzhou 450002, China
13State Key Laboratory of Pollution Control & Resource Reuse, School
of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu
210023, China
14Department of Atmospheric Science, Colorado State University, Fort
Collins, Colorado, 80523 USA
Correspondence: Xuejun Liu (liu310@cau.edu.cn) and Zhaozhong Feng (fzz@rcees.ac.cn)
Abstract. Five-year (2011–2015) measurements of gaseous NH3, NO2, and HNO3 and particulate NH4+ and NO3− in air and/or precipitation were conducted at 27 sites in the Nationwide Nitrogen Deposition Monitoring Network (NNDMN) to better understand spatial and temporal (seasonal and annual) characteristics of reactive nitrogen (Nr) concentrations and deposition in eastern China. Our observations reveal annual average concentrations (16.4–32.6 µg N m−3), dry deposition fluxes (15.8–31.7 kg N ha−1 yr−1), and wet/bulk deposition fluxes (18.4–28.0 kg N ha−1 yr−1) based on land use, ranked as urban > rural > background sites. Annual concentrations and dry deposition fluxes of each Nr species in air were comparable at urban and background sites in northern and southern regions, but were significantly higher at northern rural sites. These results, together with good agreement between spatial distributions of NH3 and NO2 concentrations determined from ground measurements and satellite observations, demonstrate that atmospheric Nr pollution is heavier in the northern region than in the southern region. No significant inter-annual trends were found in the annual Nr dry and wet/bulk N deposition at almost all of the selected sites. A lack of significant changes in annual averages between the 2013–2015 and 2011–2012 periods for all land use types suggests that any effects of current emission controls are not yet apparent in Nr pollution and deposition in the region. Ambient concentrations of total Nr exhibited non-significant seasonal variation at all land use types, although significant seasonal variations were found for individual Nr species (e.g. NH3, NO2, and pNO3−) in most cases. In contrast, dry deposition of total Nr exhibited a consistent and significant seasonal variation at all land use types, with the highest fluxes in summer and the lowest in winter. Based on sensitivity tests by the GEOS-Chem model, we found that NH3 emissions from fertilizer use (including chemical and organic fertilizers) were the largest contributor (36 %) to total inorganic Nr deposition over eastern China. Our results not only improve the understanding of spatial–temporal variations of Nr concentrations and deposition in this pollution hotspot, but also provide useful information for policy-makers that mitigation of NH3 emissions should be a priority to tackle serious N deposition in eastern China.
Our main results demonstrate that atmospheric Nr pollution in eastern China is more serious in the northern region than in the southern region. Any effects of current emission controls are not yet apparent in Nr pollution. NH3 emissions from fertilizer use were the largest contributor (36 %) to total inorganic Nr deposition. Our results provide useful information for policy-makers that mitigation of NH3 emissions should be a priority to tackle serious N deposition.
Our main results demonstrate that atmospheric Nr pollution in eastern China is more serious in...
