Effect of the ultraviolet unweighted irradiance on the compliance of sunbeds in Spain.

The use of tanning devices in Spain is regulated by the Royal Decree 1002/2002, which is based on the European standard EN60335-2-27. The European standard establishes that the total unweighted irradiance between 200 and 280 nm must not exceed 0.003 Wm-2, a requirement that the Spanish regulation modified to 0.03 Wm-2 from 250 to 295 nm. With these differences, the compliance consideration of an artificial tanning device can vary. Spectral irradiance measurements of 41 tanning devices performed with a high-resolution spectroradiometer were analyzed. None of the tanning devices had irradiances higher than 0.003 Wm-2 between 250 (the shortest wavelength measured by the spectroradiometer) and 280 nm, but the limit required by Spanish regulation was exceeded by 11 devices, of which one would have been considered compliant according to the European standard since the effective irradiance was lower than 0.3 Wm-2. Beyond noting the differences that can occur in sunbed inspections according to the established criteria, this work has shown the differences in the spectral and total values of devices in use in Spain, validating the need for periodic inspections.

Mitochondria and light: An overview of the pathways triggered in skin and retina with incident infrared radiation.

Slightly more than half of the solar radiation that passes through the atmosphere and reaches the Earth's surface is infrared. Over the past few years, many papers have been published on the possible positive effects of receiving this part of the electromagnetic spectrum. In this article we analyse the role of mitochondria in the supposed effects of infrared light based on the published literature. It is claimed that ATP synthesis is stimulated, which has a positive effect on the skin by increasing fibroblast proliferation, anchorage and production of collagen fibres, procollagen, and various cytokines responsible for the wound healing process, such as keratinocyte growth factor. Currently there are infrared light emitting equipment whose manufacturers and the centres where this service or treatment is offered claim that they are used for skin rejuvenation among other positive effects. Based on the literature review, it is necessary to deepen the scientific study of the mechanism of absorption of infrared radiation through the skin to better understand its possible positive effects, the risks of overexposure and to improve consumer health protection.

Pollutant Concentration Changes During the COVID-19 Lockdown in Barcelona and Surrounding Regions: Modification of Diurnal Cycles and Limited Role of Meteorological Conditions.

One of the consequences of the COVID-19 lockdowns has been the modification of the air quality in many cities around the world. This study focuses on the variations in pollutant concentrations and how important meteorological conditions were for those variations in Barcelona and the surrounding area during the 2020 lockdown. Boundary-layer height, wind speed, and precipitation were compared between mid-March and April 2016-2019 (pre-lockdown) and the same period in 2020 (during lockdown). The results show the limited influence of meteorological factors on horizontal and vertical dispersion conditions. Compared with the pre-lockdown period, during lockdown the boundary-layer height slightly increased by between 5% and 9%, mean wind speed was very similar, and the fraction of days with rainfall increased only marginally, from 0.33 to 0.34, even though April 2020 was extremely wet in the study area. Variations in nitrogen dioxide ( NO 2 ), particulate matter with a diameter less than 10 µ m (PM10), and ozone ( O 3 ) concentrations over a 10-year period showed a 66% reduction in NO 2 , 37% reduction in PM10, and 27% increase in O 3 at a traffic station in Barcelona. The differences in the daily concentration cycle between weekends and weekdays were heavily smoothed for all pollutants considered. The afternoon NO 2 peak at the traffic station was suppressed compared with the average daily cycle. The analysis of ozone was extended to the regional scale, revealing lower concentrations at rural sites and higher ones in urban zones, especially in Barcelona and the surrounding area. The results presented not only complement previous air quality COVID-19 lockdown studies but also provide insights into the effects of road-traffic reduction.

Outdoor testing of the photoprotection provided by a new water-based broad-spectrum SPF50+ sunscreen product: two double-blind, split-face, randomized controlled studies in healthy adults.

PURPOSE: Users often under-apply sunscreens, and one of the main reasons cited for this is the cosmetic formulation of the product. To address this, we developed a water-based sunscreen. The product underwent standard laboratory testing (ISO 24444: 2010) and was determined as sun protection factor (SPF) 50+. However, such laboratory testing does not take into account environmental factors of in-use conditions that could potentially affect sunscreen efficacy, particularly of new cosmetic formulations. We aimed to test this product in conditions more representative of real-life solar exposure, to confirm its reported laboratory efficacy. METHODS: Two double-blind, randomized, controlled, split-face intra-individual studies were conducted during summer months in Barcelona. One study compared the product against an SPF15 control (reference standard P3 of ISO 24444: 2010), while the other compared against an SPF50+ control (another commercially available sunscreen). A technician applied the products before sun exposure: investigational product (IP) to one half of the face and the respective control product to the other. Subjects spent 4-6 hrs outdoors performing quiet activities, and sunscreens were reapplied at 2 hourly intervals. A dermatologist clinically scored facial erythema at baseline and at 24 hrs. RESULTS: Sixty-five subjects were included in total. In both studies, skin treated with the IP showed no significant increase in clinical erythema scoring at 24 hrs. There were statistically significant differences between the IP and the SPF15, but not between the IP and the SPF50+ control. SPF15 did not protect all subjects against solar-induced erythema. CONCLUSION: These outdoor studies confirm the efficacy of this new SPF50+ water-based sunscreen in conditions that closer represent real-life sun exposure.

New Methodology to Evaluate Sunscreens Under Outdoor Conditions: A Double-Blind, Randomized Intra-Individual Clinical Study of a Water-Based Broad-Spectrum SPF50+ Versus SPF15 (P3) and SPF50.

INTRODUCTION: This study explored a new method to test sunscreens in outdoor conditions (very high to extreme ultraviolet [UV] radiation) approximating real-life solar exposure while maintaining scientific standards and acceptable conditions, and assessed the efficacy of a water-based sun-protection factor (SPF) 50+ versus a reference SPF15 and two comparator SPF50+ products. METHODS: Thirty-five subjects underwent testing in summertime Mauritius. In each subject, five test areas were marked on the back. One area was left unprotected, and four sunscreens were applied to the others: investigational product (IP), SPF15 (ISO 24444:2010 reference standard P3), and two marketed SPF50+ controls. Subjects spent 1-2 h (depending on skin type) in the sun. After 24 h, erythema was assessed by clinical scoring (0-5) and colorimetry (a*, L*, and ITA). Secondary endpoints were correlation between clinical and colorimetry assessment, product tolerability, and total UV radiation received. RESULTS: All subjects were exposed to a very high UV index (≥ 8) and 30/35 were exposed to an extreme UV index (≥ 11). The IP showed statistically significant differences in clinical erythema scoring compared with unprotected skin and SPF15, but not with SPF50+ controls. On colorimetry, differences in a* (redness) and L* (lightness) reached statistical significance for the IP vs SPF15 but not vs SPF50+ controls. Clinical and instrumental erythema assessment correlated strongly (Spearman's rho 0.663). No tolerability issues were reported. CONCLUSION: This exploratory study confirmed the ability of this outdoor model to discriminate sunscreens with different SPF using clinical evaluation as an objective measure. The water-based sunscreen maintained its efficacy in outdoor conditions of very high to extreme UV radiation: it was superior to SPF15 and comparable to SPF50+ controls in preventing erythema. The method used represents an option for sunscreen efficacy comparison outside of the laboratory. FUNDING: Isdin.

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.

Ultraviolet spectral distribution and erythema-weighted irradiance from indoor tanning devices compared with solar radiation exposures.

Concern regarding the impact of indoor tanning devices on human health has led to different regulations and recommendations, which set limits on erythema-weighted irradiance. Here, we analyze spectral emissions from 52 tanning devices in Spanish facilities and compare them with surface solar irradiance for different solar zenith angles. Whereas most of the devices emitted less UV-B radiation than the midday summer sun, the unweighted UV-A irradiance was 2-6 times higher than solar radiation. Moreover, the spectral distributions of indoor devices were completely different from that of solar radiation, differing in one order of magnitude at some UV-A wavelengths, depending on the lamp characteristics. In 21% of the devices tested, the erythema-weighted irradiance exceeded 0.3Wm(-2): the limit fixed by the European standard and the Spanish regulation. Moreover, 29% of the devices fall within the UV type 4 classification, for which medical advice is required. The high variability in erythema-weighted irradiance results in a wide range of exposure times to reach 1 standard erythemal dose (SED: 100Jm(-2)), with 62% of devices requiring exposures of <10min to reach 1 SED. Nevertheless, the unweighted UV-A dose during this time period would be from 1.4 to 10.3 times more than the solar UV-A dose.

Contribution of UVA irradiance to the erythema and photoaging effects in solar and sunbed exposures.

Even though UVA irradiance had not been considered detrimental to human skin for years, nowadays it is recognized for its role in photoaging and other biological responses. The ratio UVA/UVB is about 17 at a solar zenith angle (SZA) of 20° and it is almost constant up to 60° when it rapidly increases since the UVB wavelengths (280-320nm) are more attenuated than the UVA waveband (320-400nm). For a constant SZA, the ratio increases with the ozone content. The UVA component of the solar erythemal irradiance ranges from 20% at 20° to 30% at 60°, whereas it varies from 50% to 80% in the two different types of measured sunbeds. Moreover, the different spectral distribution of the lamps used for artificial tanning leads frequently to high UVA doses. The biological responses related to skin photoaging (skin sagging and elastosis) could be around fourfold the equivalent solar irradiance at midday in summer midlatitudes and they can be important in unprotected UVA exposures to sunbeds. The UVA dose accumulated during the time required in reaching 1 minimum erythemal dose (MED) increases with the SZA since the exposure durations are longer. Indeed, seasonal differences in the mean UVA dose are observed due to variations in the ozone content that results in longer exposure times without erythema. Although an artificial tanning session is usually shorter than one hour, the UVA dose from sunbeds during the time for 1 MED for skin type II (250Jm(-2)) can be 2-4 times larger than the solar dose, depending on the lamp spectral emission.

Analyzing UV-B narrowband solar irradiance: comparison with erythemal and vitamin D production irradiances.

The heliotherapy and the phototherapy are mainly focused on taking benefit of the therapeutic effects of the ultraviolet (UV) irradiance on different skin diseases. The use of UV-B narrowband lamps, with emissions centered at 311 nm, has spread out among the dermatologist community because of its high therapeutic effect in comparison with its low erythema dose. For cloudless sun exposure, the balance of solar erythemal and solar narrowband (NB)-equivalent irradiances depends on several factors such as the solar zenith angle (SZA), the total ozone column (TOC) and the altitude. For SZA below 55°, the ratio of solar UV-B narrowband and erythemal irradiances increases with the SZA whereas the ratio of vitamin D production and erythemal irradiances decreases with the SZA with the maximum around midday. Furthermore, the solar NB ratio also increases with the TOC because the shorter wavelengths of the erythemal action spectrum are more affected by the ozone absorption processes. Considering the daily variations of the ratio between narrowband and erythemal irradiance, sun exposures avoiding midday hours are recommended in order to prevent negative side-effects. However to accumulate great NB doses and sufficient vitamin D in winter months is difficult because the time exposures may be longer than the day duration.