Worried about the coronavirus outbreak, Ms Maggie Weng bought an ultra-violet (UV) box sanitiser two weeks ago so that she can sterilise her smartphone regularly.
The pencil case-like $90 gadget, made by Hong Kong's Momax Technology, uses UV light to kill germs that linger on small personal items such as smartphones and keys.
She could use sanitiser wipes to clean her smartphone, but prefers the convenience of the new gadget, which doubles as a wireless charging pad.
"I like that it can also charge my smartphone wirelessly, so it is not just a one-usage device," says the 36-year-old finance executive.
For Ms Claire Huang, she uses her recently bought UV box sanitiser - made by Hong Kong company Lexuma - for sterilising her smartphone, jewellery and keys.
"I have a young child to take care of, so the shorter the time it takes to sanitise my stuff, the better," says the 34-year-old mother and homemaker.
Like Ms Weng and Ms Huang, many people in Singapore have been buying UV box sanitisers since the Covid-19 outbreak, to clean their carry-along items harbouring viruses and germs.
These gadgets come from a wide array of lesser-known electronic brands. A search on the website of online retailers Lazada and Shopee yielded products with brands such as Momax and Lexuma.
Lazada Singapore says its sales of UV box sanitisers last month were seven times that of February. Furthermore, sales in the first week of this month have already matched that for the whole of March.
According to iCentral Mobile, the local distributor of Momax, sales of Momax UV box sanitisers here jumped tenfold from February to last month.
The local distributor of Lexuma's UV sanitisers, iMercury, says it used to sell at most 30 units a month here. Last month, sales rocketed by more than five times compared with that in February .
The high demand for such gadgets is seen elsewhere too. PhoneSoap, a United States maker of UV sanitisers for smartphones and tablets, and famed for appearing in the popular television series Shark Tank, has sold out its inventory and is asking for customers to pre-order on its website.
Hong Kong smartphone case maker Casetify, which launched its UV box sanitiser at the end of last month, has also run out of the product. A Casetify representative says: "We released hundreds of units and we sold out within days."
PhoneSoap representative Kelli Sprunt attributes the increase in sales of her company's UV sanitisers to the Covid-19 pandemic.
"While it's hard to know what course this pandemic will take, there's no denying there is a heightened awareness around how germs and bacteria are spread," she says.
Another sign of the growing interest in using UV light as a sanitiser: Samsung Singapore has been offering free UV sanitising services to those who own Samsung Galaxy smartphones since the end of last month.
It has installed industrial-grade UV box sanitisers at Samsung Service Centres at Plaza Singapura, VivoCity and Westgate, which will remain open during the circuit breaker period.
There seems to have been no definitive studies so far on the effectiveness of both UV box sanitisers and UV light itself as a germicide against Sars-CoV-2, the virus that causes the Covid-19 disease.
However, Associate Professor Richard Sugrue from the School of Biological Sciences in Nanyang Technological University notes that UV light, in particular UV-C light, disrupts the DNA of germs and viruses, thereby killing them or rendering them inactive. UV-C is a band in the UV spectrum with wavelengths between 200 and 280 nanometers.
He says UV-C light is used in laboratories to inactivate a variety of viruses in virology experiments. It is thus likely that, as with other viruses, UV-C light will be able to inactivate Sars-CoV-2.
He adds: "Since Sars-CoV-2 is able to spread by poor personal hygiene (via contaminated surfaces), any method that can conveniently sterilise implements that are used by people on a daily basis is a positive."
Dr Teo Tee Hui, senior lecturer of engineering product development at the Singapore University of Technology and Design, says: "Studies show that UV-C light is so far the most effective way of killing germs on the smartphone."
It could be a good idea to regularly sanitise our smartphones anyway, as many experts have pointed to the unhygienic conditions these devices can typically get into.
In 2012, microbiologist Dr Charles Gerba from the University of Arizona, who has written more than 500 journal articles and books on subjects such as epidemiology and pathogen detection, found that mobile phones carry 10 times more bacteria than most toilet seats.
In a 2011 study, researchers at the London School of Hygiene and Tropical Medicine found that one in six smartphones has faecal matter on it.
As for the use of UV box sanitisers, Prof Sugrue says it is important to note that a one-time exposure to UV-C light will not prevent new contamination. Consumers should also strictly follow the instructions and health warnings of these devices.
Dr Teo recommends closing the box tightly while using these UV box sanitisers, as UV light can destroy cells. "Do not let your kids play with the UV box sanitisers, as the UV light looks lovely but could destroy the eyes if one stares at it too closely," he adds.
A version of this article appeared in the print edition of The Straits Times on April 15, 2020, with the headline Coronavirus: Demand spikes for UV sanitisers to clean phones . Subscribe