Nail dryer devices: a measured spectral irradiance and labelling review

The popularity of nail beauty has increased during the last few years in Spain, as well as in other countries. Nowadays there are a large number of nail dryer devices in the market with ultraviolet (UV) fluorescent lamps, light emitting diodes (LED) or a combination of both. The different spectral emissions of each individual nail dryer device require particular nail polishes, which are polymerized by specific wavelengths and a controlled exposure time to achieve the desired results. We have measured and analyzed the emission of 28 nail dryer devices currently in use in Spanish beauty centers. The emission of each individual nail dryer device showed a particular spectral distribution and maximum intensity, especially those with fluorescent lamps or LED/UV combinations. About 30% of the devices emitted more UV-A radiation than that received in Barcelona at solar noon in summer. Nevertheless, in all cases the erythemal irradiance was low, similarly to ambient values at solar noon in winter or when the solar altitude is low. The erythemal doses corresponding to a typical session were, therefore, lower than those received from sunlight at summer midday at equivalent exposure times. The biological irradiances for photoaging (skin sagging and elastosis) showed high variability depending on the device, especially for fluorescent lamps. Since the emission of LED-based devices is centered in the visible region, erythemal and photoaging irradiances were low. An analysis of the labelling showed that 85% of the devices had a visible label, although 23% contained some errors, according to the EN 60335-1 guideline.