The impacts of reactive nitrogen (Nr) on the environment significantly increase with population and rapid urbanization. In order to study gaseous Nr and Nr loads to waterbodies at the provincial scale, we established anthropogenic emission inventories in prefecture-level cities in Fujian Province and analyzed the changes in Nr emissions for the years 2000, 2005, and 2010. The total Nr emissions were calculated as 538.4, 587.0, and 620.0 Gg in those three years, respectively. The emissions of Nr increased in nine prefecture-level cities except in Zhangzhou. Among these nine cities, Putian is the fastest growing one. The largest emitters were Zhangzhou and Quanzhou, while Ningde and Xiamen were the smallest ones. Agricultural ecosystems and livestock were the main sources of Nr emissions, both of them accounting for more than 90% of total anthropogenic Nr emissions. Despite rapid growth, energy activities had a minor contribution to total Nr emissions. The per area Nr emissions of each prefecture-level city were highest in Xiamen in the southeast coastal area and lowest in Sanming located in the northwest inland region in 2010. However, the patterns of GDP, population, and emission intensities showed the opposite trends to per area Nr emissions, lowest in Xiamen and highest in Nanping. We further discussed the significance of Nr emissions reductions in different areas based on the analysis of the characteristics of Nr emission sources in prefecture-level cities. The results provide a scientific basis for reducing Nr emissions in Fujian Province and its prefecture-level cities.
Keywords: Fujian Province; anthropogenic Nr emissions; distribution pattern; emission intensity; mitigation and regulation.