As shown in Figure 1, 78 (33%) fabrics had UPF <15 (red), 45 (19%) had UPF ≥ 15 and < 30 (yellow), and 113 (48%) had UPF ≥ 30 (green). More than 70% of the wool, polyester, and fabric blends, and less than 30% of the cotton, linen, and viscose fabrics had UPF values of 30+ (Tab. 1). Fabrics with black, navy-blue, white, green, or beige colours provided most frequently UPF values of 30+. Detailed data of white and black fabrics are shown in Figure 2.
As parameters are rarely independent, systematic research to quantify the effect of various manufacturing methods is difficult. The UPF of a garment depends on a number of factors, including fabric construction, type, colour, weight, thickness, finishing processes, and presence of additives such as UV absorbing substances (e.g., titan dioxide, brightening agents), etc. Moreover, the UV protection provided by a garment during use depends on wash and wear, including stretch and wetness . Thus, the UPF of a fabric is influenced by fabric properties and the complexity of interaction between these properties makes it impossible to predict the UPF or to generalize comparison between e.g. cotton vs polyester (Tab. 1) or black vs white (Fig. 2), nor is it sufficient to hold a fabric to the light and assess the amount of light seen through the spaces.
The aim of the presented study was to investigate UV protective properties of typical summer fabrics that are currently available on the market. Although it was not possible to study the parameters independently we have demonstrated the following trends. Polyester and wool fabrics usually provide sufficient UV protection (UPF 30+), while other fabrics, such as cotton, linen, and viscose, frequently offer poor UV protection. We showed that dark-coloured fabrics frequently have UPF values of 30+. Nevertheless, also white fabrics may provide sufficient UV protection depending on other parameters such as tightness of weave and fibre type. The most striking result however is the fact that 78 fabrics (33%) have an insufficient UPF of less than 15, and only 113 fabrics (48%) fulfilled the requirements of the European standard for UV protective clothing, that is UPF 30+ . Similar results have been found in previous studies performed in Switzerland, Germany, and Australia [8–10].
The question arises, how would the sun-aware consumer be able to choose the 'right' garment, with a third of summer clothes providing insufficient protection and only about a half of the fabrics providing UPF 30+ as recommended by the forthcoming European standard, respectively?! Therefore, UV protection of apparel fabrics should be measured and labelled in accordance with a standard document. This is especially true for children's clothing. A UPF of 30+ may be resistant against the effects of stretch, wetness, and environmental stresses. Besides, UPF values obtained by measurements in real exposure situations are usually higher than those obtained by conventional laboratory testing which represents a 'worst-case scenario' (11–13). Apart from a sufficiently high UPF the design of the garment is the crucial factor in sun protection by clothing. The European standard  includes therefore the following stringent requirements for the design of garments: 1) clothing designed to offer UV protection to the upper body must provide at least coverage from the base of the neck down to the hip and across the shoulders down to three quarters of the upper arm 2) clothing designed to offer protection of the lower body (from the waist to below the patella) must similarly provide complete coverage (Fig. 3).
In reality, in European countries such as Germany there is only a market for children's UV protective clothing. Correspondingly, there are only a few manufacturers and traders in Germany dealing UV protective clothing and most of them provide exclusively UV protective clothing for children. By contrast in Australia, which has considerably higher levels of solar UV radiation and higher incidences of skin cancer, State Cancer Councils sell sunscreens, sunglasses, hats, and UV protective clothing to the public at a reasonable cost – an important attempt to widen their use [9, 10].