“You would literally be frying people,” says Dan Arnold, laughing in disbelief.

Arnold works for UV Light Technology, a company that provides disinfecting equipment to hospitals, pharmaceutical companies and food manufacturers across the UK. Recently, as the global anxiety about Covid-19 has reached extraordinary new heights, he’s found himself fielding some unusual requests.

“We had an enquiry from a private individual about our equipment, saying ‘Well, why can't we just get one of your UV lights and put it up on the exit to the supermarket – people can stand under it for a few seconds before they go in’,” he says.

Among the abundant “health” advice that has been swarming around the internet in recent weeks, the idea that you can disinfect your skin, clothing or other objects with UV light has proved extremely popular – and even been mentioned by the US President.

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So is this a good way to protect yourself from Covid-19? And is it true that since “the new coronavirus hates the sun”, sunshine will immediately kill it, as some reports on social media have claimed?

In short: no. Here’s why.

Dangerous rays

Sunlight contains three types of UV. First there is UVA, which makes up the vast majority of the ultraviolet radiation reaching the Earth’s surface. It’s capable of penetrating deep into the skin and is thought to be responsible for up to 80% of skin ageing, from wrinkles to age spots.

Next there’s UVB, which can damage the DNA in our skin, leading to sunburn and eventually skin cancer (recently scientists have discovered that UVA can also do this). Both are reasonably well known, and can be blocked out by most good sun creams.