Answer to Question #12298 Submitted to "Ask the Experts"

What are the health effects of exposure to Vacuum ultraviolet (UV) (185 nm) radiation? What time scale of exposure would result in a health effect? Are there special gloves that can be used while working with it?

To address your question, we offer the following background information. UV light is a more energetic light than visible light, but it cannot be seen by the human eye. When using UV light sources, the blue color that is seen is light at the lower end of the visible spectrum, just above the 400 nm upper limit of UV light. UV light is further divided into four spectral ranges called UV-A, UV-B, UV-C, and vacuum UV (V-UV). None of these are visible to the human eye. Of these spectral ranges, UV-C is the most damaging as it can cause damage to cells, deoxyribonucleic acid (DNA), and proteins.

In the picture you supplied to us, the V-UV light source is in a collimated (focused) housing that reduces the amount of V-UV that could be considered to be stray light with a few centimeters distance between the collimator and the target. The light exiting the collimator will be a cone with some stray V-UV possibly reflected from the surface. The stray light could be further controlled by adding typical optical glass according to the United Kingdom's National Physical Laboratory. Besides blocking the transmission of the 185 nm light, the added glass will also block the transmission of any wavelengths associated with UV-C spectral range. Furthermore, the V-UV light also is strongly absorbed by the oxygen in the air resulting in ionizing the oxygen.

The amount of V-UV damage your hands might receive cannot be determined since we have no information on the type of bulb used, the intensity of the light, or the area irradiated. The possible damage will be related to the wattage in (joules per second), the exposure time, and the area irradiated (square centimeters). For reference, irradiation of human skin fibroblasts for 15 seconds with 10 joules/square meter of 254 nm UV-C light will damage less than 1% of the DNA in these cells (Charp and Regan 1985).

Although we cannot tell you with any certainty about the hazards to your hands from short-term exposure to the V-UV light, you can protect them by wearing protective clothing such as nitrile gloves and, if possible, keeping your hands behind a glass shield as much as possible. You might also consider in your experimental protocol putting your samples in a small glass box with a removable lid if this does not alter your parameters to any great extent.

In summary, exposure to V-UV can be hazardous to human tissues; however, V-UV is strongly absorbed by oxygen in the air, so your possibility of exposure is small. To further protect yourself, we would recommend you wear protective nitrile gloves and use a small glass shield as protection from stray V-UV light that might escape the collimated beam.

Paul A. Charp, PhD

Reference

Charp PA, Regan JD. Inhibition of DNA repair by trifluoperazine. Biochim Biophys Acta 824:34–39; 1985.