Name a technique to control the nitrous oxide emissions.

• A. Selective Catalytic Reduction
• B. Electrostatic Precipitation
• C. Activated Carbon Filtration
• D. Condensation

Answer: (A)

Reducing nitrous oxide (NOx) emissions relies on a post-combustion treatment that chemically transforms NOx in the exhaust. Selective Catalytic Reduction accomplishes this by injecting a reductant, usually ammonia or urea, into the hot gas as it passes over a catalyst bed. The catalyst—commonly a vanadium-tanium/tungsten or zeolite-based material—drives reactions that convert NOx into nitrogen and water. This approach is highly effective across a wide range of temperatures and is widely used in power plants and diesel exhaust systems. It’s important to control the ammonia dosing to avoid slip and to maintain the catalyst for sustained performance. The other options don’t target NOx: electrostatic precipitation removes particulates, activated carbon filtration targets certain gases like mercury or VOCs, and condensation relies on cooling to separate components, not on transforming NOx.