and the proportion was as high as 27–48% in May and June when toxic blooms were
initiated and proliferated.
1.5 Regulation Strategies of Reactive Nitrogen Emission
As increasing atmospheric emission and deposition of reactive N in China have
substantially contributed to air pollution and significantly threatened ecosystem
health, national N regulation is of great importance to mitigate negative effects of
reactive N in the environment. Agricultural systems and energy production systems
are major sources of reactive N emission to the atmosphere. In Chap. 13, Yan et al.
reviewed the N inputs and losses of reactive N in China’s agricultural systems as
well as the strategies to increase N use efficiency. They show that the total application of N fertilizer has increased by 150% in China’s croplands from 1980 to 2010,
while N use efficiency has decreased continuously. They also reviewed N management strategies to improve N use efficiencies, such as integrated soil-crop system
management, knowledge-based N management and livestock manure partially substitute synthetic fertilizer, as well as national N regulation projects to reduce N losses
from agricultural systems, such as soil testing and fertilizer recommendation program and “zero growth of the fertilizer and pesticide consumption by 2020” plan. In
Chap. 14, Zhao and Xia evaluated the effect of recent national policy strategies of
energy conservation and emission reduction on the emissions of SO 2 and NO x . SO 2
emission has reduced substantially since 2006 due to the improved use of flue gas
desulfurization in the power sector and implementation of new emission standards in
key industrial sources; NO x emission has started to decrease from 2011 due to the
penetration of selective catalytic/non-catalytic reduction systems in the power sector.
Transportation is playing an increasingly important role in regional air pollution,
with the emissions from stationary sources gradually controlled.
1.6 Outlook
China has experienced rapid economic growth via industrialization and urbanization
over the past four decades (1978–2018), while this growth has also consumed
increasing energy and raw materials and induced various environmental issues.
The increase of reactive N emission and deposition is one example that has attracted
public concerns due to its contribution to air pollution and negative effects on
ecosystem services. In general, atmospheric reactive N emission is closely associated with the occurrence of secondary aerosol (e.g., PM 2.5 ) pollution, increasing
tropospheric O 3 concentrations, and acid deposition. High-level N deposition in
China can significantly alter structure and function of various ecosystems in China,
especially those (semi-)natural ecosystems in eastern and southern regions. In view
of these environmental issues, the Chinese government has recently implemented
1 An Overview of Atmospheric Reactive Nitrogen in China from a Global Perspective
7
initiated and proliferated.
1.5 Regulation Strategies of Reactive Nitrogen Emission
As increasing atmospheric emission and deposition of reactive N in China have
substantially contributed to air pollution and significantly threatened ecosystem
health, national N regulation is of great importance to mitigate negative effects of
reactive N in the environment. Agricultural systems and energy production systems
are major sources of reactive N emission to the atmosphere. In Chap. 13, Yan et al.
reviewed the N inputs and losses of reactive N in China’s agricultural systems as
well as the strategies to increase N use efficiency. They show that the total application of N fertilizer has increased by 150% in China’s croplands from 1980 to 2010,
while N use efficiency has decreased continuously. They also reviewed N management strategies to improve N use efficiencies, such as integrated soil-crop system
management, knowledge-based N management and livestock manure partially substitute synthetic fertilizer, as well as national N regulation projects to reduce N losses
from agricultural systems, such as soil testing and fertilizer recommendation program and “zero growth of the fertilizer and pesticide consumption by 2020” plan. In
Chap. 14, Zhao and Xia evaluated the effect of recent national policy strategies of
energy conservation and emission reduction on the emissions of SO 2 and NO x . SO 2
emission has reduced substantially since 2006 due to the improved use of flue gas
desulfurization in the power sector and implementation of new emission standards in
key industrial sources; NO x emission has started to decrease from 2011 due to the
penetration of selective catalytic/non-catalytic reduction systems in the power sector.
Transportation is playing an increasingly important role in regional air pollution,
with the emissions from stationary sources gradually controlled.
1.6 Outlook
China has experienced rapid economic growth via industrialization and urbanization
over the past four decades (1978–2018), while this growth has also consumed
increasing energy and raw materials and induced various environmental issues.
The increase of reactive N emission and deposition is one example that has attracted
public concerns due to its contribution to air pollution and negative effects on
ecosystem services. In general, atmospheric reactive N emission is closely associated with the occurrence of secondary aerosol (e.g., PM 2.5 ) pollution, increasing
tropospheric O 3 concentrations, and acid deposition. High-level N deposition in
China can significantly alter structure and function of various ecosystems in China,
especially those (semi-)natural ecosystems in eastern and southern regions. In view
of these environmental issues, the Chinese government has recently implemented
1 An Overview of Atmospheric Reactive Nitrogen in China from a Global Perspective
7