Portable air sterilizer using UV light.

I was thinking about using uv light to sterilize breathing air.
I got the idea from the 18V Milwaukee vaccum cleaners.
Basically, unit sends the air through a thin chamber where the air passes under a UV light to kill bacteria and viruses.

I don't know how feasible this would be.
I'm thinking if the chamber is thin then there is less cross section for the organisms to hide in.

Downsides?
Air may not have enough dwell time in chamber to disinfect effectively.
Battery power may not be long enough to be practical.
Ozone production?

Just a thought.