On Tuesday, January 21, 2020 at 2:43:01 PM UTC-5, Tim R wrote:
On Saturday, January 18, 2020 at 4:11:06 PM UTC-5, KC JONES wrote:
I've had a germicidal lamp more or less in storage for a number of
years, but recently brought it out to sterilize a room where a person
had been sick. However, I don't know if it still emits the germ killing
UVC spectrum. What's a quick way I could tell for sure? Thanks.

It's a good question (if not a good use.) Amazon is full of air purifiers that include UV light inside the enclosure. That light must degrade over time, if it even works at all.

A quick google says change the bulb every 12 months. I bet it isn't cheap, either.

So, A your lamp probably kills germs for about 6 inches, and B it's probably worn out by now anyway.

Snip from a UV website:
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What distance and how long would I have to expose an article to germicidal ultraviolet to sanitize it?
The exposure necessary to inactivate microorganisms is a product of time and ultraviolet intensity. High intensities for a short period of time, or low intensities for a long period of time are fundamentally equal in lethal action on infectious microorganisms. As a rule of thumb, at two inches away from the STER-L-RAY ® germicidal ultraviolet lamp, most common bacteria and virus are inactivated within five seconds of exposure. For specific recommendations, please call our staff with the details of your application (including area available for the fixture, how far the fixture will be from the article, etc.) The more information you can provide, the better.