The use of UV-C lights has been gaining popularity as a way to disinfect and sanitize surfaces. However, with the use of these devices, it has often been observed that there is a residual odor after disinfection, also known as volatile organic compounds (VOCs). This odor has been described as a sulfuric odor similar to that of rotten eggs, garlic, or burnt hair. Ozone gas is another byproduct of UV-C lights that can be detected by smell.
People describe the smell of ozone as an electric spark or metal, so it is likely that this is what you are smelling when your oven starts. As the lights continue to shine, UV-C rays will produce ozone that will be distributed throughout the house when the oven is turned on. Most people will smell ozone at concentrations of about 0.01 parts of ozone per million parts of air, that is, 0.01 ppm. When you no longer smell ozone, its concentration should be below 0.01 ppm.
Medical devices that produce ozone must not produce more than 0.050 ppm as regulated by the Food and Drug Administration. In short, the use of these lights is not dangerous inside the system and any metallic smell that emerges may be due to the production of ozone gas by UV-C lights. When UV-C light hits metals, the light has enough energy to eject electrons from many metals, especially aluminum.
