A new M&M-sized UV tracker can accurately tell people in real time how pollution, humidity, allergens, and, of course, sunlight, are damaging their skin. 

Researchers at Northwestern University tested out the My Skin Track UV Sensor that L’Oreal’s upscale skin care line, La Roche Posay put out last month. 

The device is the world’s smallest and can be stuck to a fingernail, clipped to a hat or hung from a chain to monitor exposures.

L’Oreal and the Northwestern team hope might help people protect themselves and curb the millions of new cases of skin cancer a year.

Sensors go for $60 a piece, are virtually indestructible, show promise for helping wearers improve their skin protection and may even help doctors dose light therapy for psoriasis and other skin conditions.    

There is no more common cancer than basal cell carcinoma, which kills 3,000 people a year. 

Despite the invention of sunscreens that (purport to) go up to 100 SPF, constant warnings from public health officials and dermatologists, rates just keep climbing. 

In 1999, 40,777 new cases of melanoma were diagnosed in the US. 

By 2016, there were 80,442 new cases a year.

Though it is now widespread knowledge that tanning beds pose significant cancer risks, a ‘tanned’ appearance remains popular – and so do UV beds. 

The ozone layer is also dissipating as a result of global warming and pollution, further exposing us to the sun’s rays.  

Plus the population is aging, and the older a person is the greater the risks are that their cells will mutate, leading to cancer. 

Too often, people also simply don’t realize how vulnerable they are to the sun. 

Cloud cover, windows, beach umbrellas and the water may, intuitively, seem to offer protection from the sun. 

But in reality, the are far from comprehensive protection. Cloud cover, for example, allows about 80 percent of UV radiation to pass through it, and about 17 percent of the sun light we absorb is deflected from the sand below our feet, so an umbrella is doing nothing to stop it. 

‘If you’re out in the sun at noon in the Caribbean, that sunlight energy is very different than noon on the same day in Chicago,’ study co-author Dr Steve Xu, a Northwestern dermatologist explained. 

Even bearing all of this in mind, on a day-to-day basis, we just don’t have a very clear sense of how much UV radiation we’re soaking up – much less how much pollution, pollen or humidity – might be coming into contact with our skin and damaging it.   

The Northwestern University team wanted to change that, so they developed a tiny device that could measure these exposure, at nearly any wavelength. 

They made a wearable tracker that was battery-free – operating instead on solar power – can scarcely be drowned or smashed. 

In the recent tests for the device, students were given license to kill it, or at least to try very hard to do so. 

They tried drowning it in bucket of water, smashing it on the ground and even running it through the dishwasher. 

The My Skin Track UV survived all the torture it was subjected to. 

‘There are no switches or interfaces to wear out, and it is completely sealed in a thin layer of transparent plastic,’ said lead study author and Northwestern biomedical engineer, Dr John Rogers, said. 

‘It interacts wirelessly with your phone. We think that it will last forever.’ 

A tiny sensor in the wearable translates light into electricity, and based on the strength of the tiny charge emitted the device can in turn translate that into a a voltage read out that is sent to the paired phone. 

The paired phone can then compare that voltage information to a whole network of to-the-minute online data about the current UV index, weather and other conditions in that location.   

It also goes a step further than simply tracking overall UV exposure, and notifies users what kind of ultraviolet light is beating down on them. 

Different wavelengths of light are associated with different risk levels, with the shortest rays posing the greatest danger.  

‘Being able to split out and separately measure exposure to different wavelengths of light is really important,’ said Dr Rogers. 

‘UVB is the shortest wavelength and the most dangerous in terms of developing cancer. A single photon of UVB light is 1,000 times more erythrogenic, or redness inducing, compared to a single photon of UVA.’ 

Weighing about the same amount as a  rain drop, the research team – and of course, L’Oreal, which sells the sensor – hope that it will make it far more practical for people to keep track and take caer of their skin. 

‘We hope people with information about their UV exposure will develop healthier habits when out in the sun,’ Dr Xu said. 

‘UV light is ubiquitous and carcinogenic. Skin cancer is the most common type of cancer worldwide. 

‘Right now, people don’t know how much UV light they are actually getting. This device helps you maintain an awareness and for skin cancer survivors, could also keep their dermatologists informed.’