Hmm, I wonder how effective that would be. My small home's ventilation system is currently taking in about 100m³ of fresh air per hour. That's about 1600L/minute. Let's assume the intake duct is about 20cm in diameter, and assume we can place a bulb to illuminate a 50cm stretch of pipe. That's a volume of about 16 liters. So the air would be in visible range of the bulb for about half a second. Would that be enough for a UV bulb to do anything?
This was back of napkin maths, could be way off.
Edit: sanitizing incoming air is probably pretty useless, as the outdoor concentration of pathogens is likely very low to begin with.
I’ve seen some claims that it can destroy viruses on some medium. Imagine a filter in the light catching virus particles or particles that have viruses. The light destroys them while they’re stuck in place. I would need some independent testing to verify that claim.
This was back of napkin maths, could be way off.
Edit: sanitizing incoming air is probably pretty useless, as the outdoor concentration of pathogens is likely very low to begin with.