Far UVC (222nm) Ultraviolet Germicidal
Far UVC of the 222nm wavelength and below is currently being researched as a potential alternative to conventional germicidal lights of the 253.7nm wavelength. Few products in this category are currently affordable for the general public, but these items and others similar to it may be available to commercial buyers, government institutions, hospitals, and universities, or for manufacturers developing new equipment.
About 222nm Far UVC Lighting
For the general public, homeowners, consumers, businesses, and medical/government institutions, conventional UV air/surface disinfection and UV water purification products still make the most sense in regards to price and availability.
Far UVC technology with 222nm output is on the cutting edge of medical lighting right now, not readily available, and still cost prohibitive compared to equipment utilizing 254nm UVC light bulbs. This category of products exists for informational and educational purposes, or for those interested in purchasing products at the leading edge of lighting technology.
Please note that at least one study (PDF) showed damage to human skin after exposure to equipment utilizing far UVC excimer lamp technology. According to that evaluation of a far UVC device, "At low doses below the threshold bacteriostatic effect, the source was capable of inducing both erythema and CPD formation in human skin." Until more research is done, we do not recommend using unshielded far UVC lights in areas occupied by humans or animals. Some people believe this study to have been sufficiently disproved, however.
Is Far UVC Safe for Human Skin?
According to the Illumination Engineering Society, far UVC excimer light bulbs can still pose a threat to human skin and eyes. Several studies have shown that far UVC has not damaged the skin or eyes of some mammals, while other studies have been inconsistent. One study even showed skin damage to humans after exposure to far UVC, although that study is also being questioned for accuracy.
The big danger is that, if the far UVC light source does not block longer-wavelength light from passing through the bulb envelope, it may still be dangerous. Manufacturing quality could play a large part in making this technology safe in the future, but small differences in wavelength can make a big difference in the effect on human health. Buyers should verify the full spectral distribution graph of any far UVC lights they purchase.
The bottom line for safety is that, until more research is done on healthy (and unhealthy) human skin and eyes, and unless the proper wavelength of light can be guaranteed throughout the effective life of the far UVC light source, long term far UVC is not safe to expose to skin or eyes.
Further Resources
- Buonanno M, Ponnaiya B, Welch D, Stanislauskas M, Randers-Pehrson G,Smilenov L, Lowy FD, Owens DM, Brenner DJ. Radiation Res. Germicidal efficacy and mammalian skin safety of 222 nm light. 2017; 187:493-501.
- Woods JA, Evans A, Forbes PD, Coates PJ, Gardner J, Valentine RM, Ibbotson SH, Ferguson J, Fricker C, Moseley H. The effect of 222-nm phototesting on healthy volunteer skin: A pilot study. Photodermatol Photoimmunol Photomed. 2015; 31:159-66
Who Can Buy Far UVC?
Currently, many far UVC fixtures and components (lamps and ballasts) are now available for sale to the general public.
We carry a fairly extensive line of far UVC products from selection of the manufacturers currently designing and producing 222nm equipment and components. However, if there is a solution that you do not see, custom products can be manufactured. Also, the line of fixtures and lamps should expand over time.
When Will Far UVC Equipment Be Available?
Far UVC equipment is being fast tracked, and many fixtures and lamps are now available.
As manufacturers design systems that utilize 222nm far UVC excimer lamps, more options will become available over the next few years, including excimer lamp/ballast combos and entire fixtures.
How Much Will Far UVC Cost?
As excimer lamp technology is relatively new and specialized, the equipment using these lamps tends to be very expensive, especially in comparison to traditional 254nm UVC fixtures and systems, and more expensive than UV pulsed xenon light sources.
A few years ago, small handheld far UVC systems cost upwards of $30,000. As of this writing, that price has fallen dramatically, with far UVC handheld devices now retailing at around $3,000. While the cost may decrease with mass production, simple far UVC equipment could cost several thousand dollars, and more advanced equipment could cost several tens of thousands of dollars.
That's Too Expensive, Are There Alternatives?
While 222nm UVC technology holds promise, 254nm UVC has long been used by hospitals, industry, and governments for air, surface, and water purification.
Precautions must be taken when using 254nm UVC equipment, but the cost is a fraction of far UVC, replacement bulbs and ballasts are widely available, and multiple options exist for air, surface, or water sanitization. UV bulbs in the UVA, UVB, and UVC spectrum come in a variety of lengths, bases, wattages, and other variations.
For the vast majority of consumers, professionals, businesses, and institutions, regular UVC bulbs and fixtures still make the most sense in terms of effectiveness and cost.
