The largest amount of nitrogen oxide emissions comes from

The largest amount of nitrogen oxide emissions comes from

• A. Industrial processes
• B. Natural sources
• C. Vehicles
• D. Power plants

Answer: (C)

Nitrogen oxides form when nitrogen in the air reacts with oxygen during high-temperature combustion. On-road vehicles are the largest source because there are countless engines operating continuously, producing a huge volume of exhaust with high combustion temperatures that generate NOx. While power plants and industrial processes also burn fuels and release NOx, the sheer number of vehicles and their frequent use typically make them the single largest source in many environments. Natural sources like lightning contribute NOx as well, but in populated areas and overall emissions tallies, human-caused vehicle emissions dominate.

Nitrogen oxides form when nitrogen in the air reacts with oxygen during high-temperature combustion. On-road vehicles are the largest source because there are countless engines operating continuously, producing a huge volume of exhaust with high combustion temperatures that generate NOx. While power plants and industrial processes also burn fuels and release NOx, the sheer number of vehicles and their frequent use typically make them the single largest source in many environments. Natural sources like lightning contribute NOx as well, but in populated areas and overall emissions tallies, human-caused vehicle emissions dominate.