UVB Lights Produce Ozone in High Amounts?

Yesterday, I added a 18W T8 Sylvania Reptistar UVB light to my grow (5% UV-B, 30% UV-A). I'm growing a single Cream Caramel (Sweet Seeds) plant and it's in the 5th week of flowering under HPS.

Two things I noticed:

• A strong ozone metallic odor each time I enter the room (like the odor produced by ozone generators).
• The smell of the plant has reduced significantly.

It's known that UV light is responsible for both the formation and destruction of O3. However, I never thought a UVB light would produce sufficient amount of this radiation to generate ozone in such a detectable amount.

Has anyone else experienced this?

I've never noticed this with my UV-b reptile light. Doesn't seem plausible, and I have not seen any data or warnings from anyone.

UV Spectrum


UV-A is the source of suntanned skin. With its relatively longer wavelength, it can penetrate the atmosphere. Applications included tanning beds and treatment of skin diseases plus insect lights.
UV-B is in the middle wavelength of the ultraviolet spectrum and has been used to treat skin diseases.
UV-C, or short wave ultraviolet radiation, is used to destroy bacteria, mold, viruses and other biological contaminants in the air, in liquids, or on surfaces.
UV-V is produced by ultraviolet lamps which produce ozone. This occurs because UV-V light reacts with oxygen to break it into atomic oxygen, a highly unstable atom that combines with regular oxygen atoms to form O3 (ozone). Ozone is good for the upper atmosphere but terrible for your lungs.

That's a very handy chart. If a lamp is optimized for UVB (280nm - 320nm) there may not be any UVC and especially UVV. I just looked up the tested spectrum for the Mega Ray reptile lamp I use and there's no output below 290nm. Very focused output primarily at 313nm, secondarily at 302, and a bit at 297.

Maybe some lamps are all over the board, but the one I chose is tested and very specific.

Rrog said:

That's a very handy chart. If a lamp is optimized for UVB (280nm - 320nm) there may not be any UVC and especially UVV. I just looked up the tested spectrum for the Mega Ray reptile lamp I use and there's no output below 290nm. Very focused output primarily at 313nm, secondarily at 302, and a bit at 297.

Maybe some lamps are all over the board, but the one I chose is tested and very specific.

Click to expand...

Mega-Ray is a very good choice for a UVB light, possibly the best.

Yea. When I started looking into UVb a few years ago, I was surprised to find that the wavelength output was really garbage on many "UV" lamps. Some were weak in the UVb I wanted. Some had 80% or more output drop after a burn in period. The MegaRay had the data and the independent documentation. I've been impressed with the lamp.