Keyphrases
United States
100%
Reduced Nitrogen
100%
Nitrogen Deposition
100%
Nitrate
60%
Ammonia
60%
Ammonium
40%
Wet Deposition
40%
Oxidized Nitrogen
40%
Rapid Development
20%
Wetting-drying
20%
Nitric Acid
20%
Fossil Fuel Combustion
20%
Ammonia Emission
20%
Excess Nitrogen
20%
Fine Particles
20%
Low Nitrogen
20%
Nitrogen Oxide Emissions
20%
Regulatory Requirements
20%
Recent Expansion
20%
Natural Ecosystems
20%
Dry Deposition
20%
Agriculture Development
20%
Second Half of the 20th Century
20%
Reactive Nitrogen Emission
20%
Total Inorganic Nitrogen
20%
Inorganic Nitrogen Deposition
20%
Ammonium Deposition
20%
Earth and Planetary Sciences
United States
100%
Emissions
100%
Wet Deposition
66%
Planetary Atmosphere
33%
Fossil Fuel
33%
Fuel Combustion
33%
Nitrogen Oxide
33%
Dry Deposition
33%
Inorganic Nitrogen
33%
Agricultural and Biological Sciences
Wet Deposition
100%
Agricultural Science
50%
Fossil Fuel
50%
Reactive Nitrogen
50%
Nitrogen Oxide
50%
Dry Deposition
50%
Material Science
Fine Particle
100%
Fossil Fuel
100%
Nitrogen Oxide
100%
Engineering
Fossil Fuel Combustion
100%
Regulatory Requirement
100%
Natural Ecosystem
100%
Chemical Engineering
Nitric Acid
100%
Nitrogen Oxides
100%