Why installing UV lights inside public transport isn’t necessarily a bright idea

It might do more harm than good
by Drei Laurel | Oct 14, 2020
PHOTO: Jerome Ascaño

Yesterday, the Department of Transportation announced that it has ordered all transportation sectors to implement a ‘one seat apart’ policy to help increase capacity and jumpstart public transit. The move comes a day after President Rodrigo Duterte gave the measure his go-signal.

Essentially, the ‘one seat apart’ policy does away with social-distancing measures recommended by the World Health Organization (WHO), which prescribes a distance of at least one meter between individuals. In a statement, the DOTr also said that it gradually plans to increase passenger capacity further “provided that plastic barriers are placed in between passengers, or that UV lights are used.”

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Yeah, that part about using UV lights in PUVs must be implemented with strict precautions.

On paper, installing UV lights on public transport sounds like a neat idea—an unobtrusive, convenient way to sterilize seats, grab handles, and other surfaces or objects commuters normally come into contact with during trips. In some environments, UV lamps are also used to destroy airborne organisms.

There’s just one issue: Depending on its application, germicidal UV light can be harmful to human beings.

There are three types of UV light: UVA, UVB, and UVC. Of the three, the US Food and Drug Administration (FDA) says UVC—which is commonly used in germicidal lamps—might be effective in inactivating SARS-CoV-2, which is the virus that causes COVID-19. Key word: might.

The agency says it’s still unknown exactly how effective UVC is against SARS-CoV-2 due to limited data, but that it has been shown to “destroy the outer protein coating of the SARS-Coronavirus,” which is different from SARS-CoV-2. UVB radiation can work against some viruses, but not SARS-CoV-2. It’s also more hazardous to humans than UVC. UVA, meanwhile, is 1,000 times less effective than either UVB or UVC, the FDA says.

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So, UVC, then? Depending on the dose and duration of exposure, UVC can be harmful to people, too.

“Direct exposure of skin and eyes to UVC radiation from some UVC lamps may cause painful eye injury and burn-like skin reactions. Never look directly at a UVC lamp source, even briefly,” the FDA stresses on its website, adding that some UVC lamps can cause irritation to the airway and degrade materials like plastic.

Just last month, actor Derek Ramsay ended up in a hospital after accidentally exposing his eye to UV light.

Further complicating matters is how effective and how risky UVC light is also depends on its wavelength and the duration of exposure. The type of bulb used will also come into play, as low-dose UVC lamps will take longer to disinfect surfaces.

Of course, it’s still too early to say the DOTr’s idea is not a good one, especially since details regarding its proposed implementation are still scarce. One possible workaround the agency can use is to incorporate UV light into the A/C systems of public vehicles, as the FDA says this is the safest implementation of UVC.

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This isn’t the first time if ever, UV light has been utilized in vehicles. UV lamps are commonly used inside ambulances for disinfection, though not while patients are inside. And earlier this year, New York City’s Metropolitan Transport Authority (MTA) looked into using UV light in a similar fashion.

Anyway, let’s see how this idea pans out. If implemented correctly, it can potentially make our commutes a whole lot safer.

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PHOTO: Jerome Ascaño
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