at-home uv sterilizers: do they actually work?
3 minute read
rather than use uv lights, health canada reccomends consumers use approved disinfectants and hand sanitizers.
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with the holiday season comes an arsenal of gimmicky products that tend to lean more to the fun side than functional. in the pandemic era, this had led to an influx of phone holders and hand-held wands that claim to sterilize phones, wallets, and even groceries with uv light. but do they actually work?
specific wavelengths of light can damage nucleic acids or protein and are effective in killing certain viruses and bacteria. however, these lights have to be fairly concentrated to kill pathogens, which is both difficult and expensive to create in smaller home devices.
humans are also susceptible to uv damage and lights that are strong enough to kill viruses can cause burns, eye damage and skin cancer. health canada recently released an alert warning consumers about uv lights and wands for home use, stating that it “has not yet received any evidence to demonstrate that uv lights can protect specifically against covid-19.” the public health body also noted that there is currently no proof that uv lights are effective against covid-19 itself and “should not be used as a substitute for prevention measures such as frequent hand washing, physical distancing, mask-wearing, and cleaning and disinfecting”
health canada recommends that anyone who has used these lights on their skin and has concerns should speak to a doctor.
uv lights also need to be of a high-enough strength to kill pathogens. if the device doesn’t have enough power, if the bulb is starting to burn out or if the device isn’t focused on the area for a long enough period of time it won’t be effective. simply flashing a wand around the room or across some groceries won’t get the desired results.
not all uv lights are created equal
light is measured on a spectrum, with visible light at 380 to 740 nm. the wavelengths of ultraviolet light are shorter than this, from 100 to 380 nm, which gives it more energy.
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in the uv spectrum, uva is the longest wavelengths, from 320 to 400 nanometers (nm) and is known to cause some cell damage and indirect dna damage. this cell damage can cause wrinkles and sunspots and may have an indirect effect on developing some forms of skin cancer. uvb is more intense than uva, and can cause burns, eye damage and can also damage protein and dna in cells. uvb radiation from the sun is what causes sunburns.
uvc, also known as germicidal uv (200 to 280 nm), is even more potent and can severely damage proteins and dna in cells. if a human is exposed to concentrated uvc light for even a few seconds, they can come away with burns and eye damage. uvc lights are used in hospitals and labs to sterilize equipment.
according to health canada, “uvc is an extremely dangerous form of uv radiation and, although it can destroy some germs on non-porous surfaces, if used on the skin, there is a risk that it can cause harm or injury.”
while a study published in the journal of photochemistry and photobiology found that relatively cost-effective uv leds can be effective in killing a form of the human coronavirus that is closely related to covid-19, the light must have a wavelength of approximately 286 nm or lower (the edge of uv-b and into the uv-c range) and must be focused on the affected area for several seconds to be effective.
for the home and office, alcohol wipes and sanitizers are a more effective manner of sterilizing equipment. apple has also released a guide saying that it is safe to wipe down any hard, non-porous surfaces of apple products with a 70 percent isopropyl alcohol wipe or clorox disinfecting wipes.
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