Questions, answered.

Light at 222 nm is absorbed by protein within the first few micrometers of tissue. In skin, that is the stratum corneum, a 5–20 µm layer of dead, keratin-filled cells, so the light does not reach the living cells beneath. Controlled studies in human volunteers observed no erythema at doses up to 500 mJ/cm². The ACGIH 8-hour skin limit at 222 nm is 480 mJ/cm².

At 222 nm, light is absorbed by the tear film and the outermost corneal cells, which the eye sheds continually. In 2022 the ACGIH raised its 8-hour eye limit at 222 nm from 23 to 160 mJ/cm². Lifelight is designed to operate within ICNIRP exposure limits.

Conventional germicidal lamps emit at 254 nm. That wavelength penetrates further, reaches living cells in skin and the eye, and is restricted to unoccupied spaces. Far-UVC at 222 nm is absorbed far more strongly by protein, which is what allows use around people.

No. Far-UVC at 222 nm is produced by krypton-chloride excimer sources, which contain no mercury. Conventional 254 nm germicidal lamps are low-pressure mercury lamps.

It depends on the organism and where it is. Airborne influenza A is reduced 90% by 0.11 mJ/cm². Coronavirus, rhinovirus and a norovirus surrogate dried on surfaces were reduced about 3.5 log at 9.3 mJ/cm². Drug-resistant bacteria on surfaces reached 3 log at 18–28 mJ/cm². On contaminated hands, one study measured about 1 log at 23 mJ/cm². See the dose–response chart on the science page.

Alcohol does not kill bacterial spores such as Clostridioides difficile and has limited activity against non-enveloped viruses such as norovirus. 222 nm inactivated a norovirus surrogate by 3.4 log on surfaces and is sporicidal, with efficacy that depends on dose.

Yes. Light does not depend on a biochemical target that resistance genes protect. 222 nm achieved 3-log reductions of MRSA, VRE and carbapenem-resistant Gram-negative bacteria on surfaces, and killed MRSA as efficiently as conventional 254 nm UV in laboratory studies.

Alcohol rub meets EN 1500 hand-test requirements, typically 3.9 to 4.4 log against E. coli with 3 mL over 30 seconds. In the only published direct comparison on hands, 222 nm at 23 mJ/cm² gave about 1 log against 1.9 log for alcohol rub. Far-UVC's advantages are breadth against spores and norovirus, zero consumables and contact-free use; results on skin depend on dose and exposure geometry.

No. Lifelight is an alternative to alcohol-based hand rub for routine hand hygiene. When hands are visibly soiled, follow your facility's protocol for washing with soap and water. Organic soil shields microbes from light, as it does from alcohol.

Seconds at the unit. There is no rub-until-dry step. By comparison, WHO guidance for alcohol rub is 20 to 30 seconds.

No refills. The light source is rated for 8,000 to 10,000 hours of operation. Clean the exterior to your facility's surface protocol.

Electricity is the only running cost: about $2.20 a year per unit at 200 uses a day, including standby. There is no product to buy or store. Use the calculator on the comparison page to model your facility.

Hospitals and clinics, long-term care, airports and transit, schools and universities, and hospitality venues. Anywhere a gel dispenser would go, without the refill route.

An alcohol rub use of 3 mL carries about 0.9 g CO₂e, most of it from producing the alcohol. Lifelight's electricity, including standby, is about 0.08 g CO₂e per use on the U.S. grid average, roughly 90% less. There is no product, packaging or shipping.

At 200 uses a day and 2–3 mL per use, between 146 and 219 L a year. Hospital-wide consumption is commonly reported at roughly 10 to 40 L per 1,000 patient-days, and the European ICU average is about 98 L.

Use the request form on the home page. Tell us your facility type and the areas you want to evaluate, and we will follow up.