Which of the following is a source of UV radiation in industrial settings?

• A. High and Low Pressure Mercury Discharge Lamps
• B. Incandescent bulbs
• C. LED lights
• D. Neon signs

Answer: (A)

Industrial UV radiation in many settings comes from mercury discharge lamps. When electric current excites mercury vapor inside the lamp, photons are emitted across the spectrum, including ultraviolet. High-pressure mercury lamps produce a broad spectrum with UV, visible, and infrared light, making them useful for processes that rely on UV exposure. Low-pressure mercury lamps emit predominantly UV-C around 254 nm, which is especially germicidal and used for sterilization and disinfection. Incandescent bulbs rely on heating a filament and give mostly visible light with a lot of infrared, so they’re not a significant UV source. LED lighting, while efficient, typically produces light through semiconductor processes and, for white LEDs, mainly visible light with little UV (unless specifically designed as UV LEDs). Neon signs glow mainly in visible colors from gas discharge and don’t serve as a primary UV source in industry.