Spectral ultraviolet albedo of roofing surfaces and human facial exposure

Abstract

Spectral field measurements were used to quantify the ultraviolet (UV) spectral albedos of four different metallic roofing surfaces. The effect of the albedos of two of these surfaces on erythemal exposure to human facial anatomical sites was quantified by UV dosimetry. The albedos of all roofing surfaces were greater than the albedo of grass. Little SZA dependence was observed for any of the surfaces. The albedos of the coloured metallic corrugated surfaces were strongly dependent on wavelength in the UVA, increasing from 3 to 12%. Facial erythemal measurements showed significant exposure enhancements over the galvanised corrugated surface compared to grass. The undersides of the chin and nose received exposure enhancements over the galvanised corrugated surface of about 1290% and 190% respectively, of the exposure of these sites over grass. It is concluded that the albedo of the galvanised surfaces are higher than those of the coloured surfaces by at least 20%, and higher than grass by at least 27%. Consequently, normally shaded facial anatomical sites receive substantially higher UV exposures over these galvanised surfaces compared to grass.

Reflected solar radiation from horizontal, vertical and inclined surfaces: Ultraviolet and visible spectral and broadband behaviour due to solar zenith angle, orientation and surface type

“…There is some photon noise present at the shorter wavelengths, but this does not affect the overall spectral distribution. The spectral RRG UV measured due to vertical surfaces is in agreement with the work of Lester and Parisi [18] in which it was found that galvanised (zinc coated steel) corrugated metal at 305nm had an albedo of 0.27. The measured spectral RRG UV is approximately 0.3 at most wavelengths in Figure 1, slightly higher than the albedo measured by Lester and Parisi.…”

“…The study for horizontal albedo of roofing material by Lester and Parisi [18] shows high albedo recorded for shiny and coated horizontal surfaces, but does not consider vertical surfaces. However, in many industrial work sites, it can be commonplace to use the metal roof cladding as wall cladding.…”

“…Irradiances on inclined surfaces affected by surrounding albedo have been previously explored [15][16][17]. Investigation of the biological effectiveness of the contribution to personal UV exposures due to the albedo of different horizontal and inclined surfaces has been investigated [18][19][20]. These effects are particularly important for outdoor workers' who should be aware of the contribution to UV exposures from such surfaces due to everyday working conditions [21].…”

Measuring the influence of UV reflection from vertical metal surfaces on humans

“…Albedo also varies according to wavelength 14 which is important to biological processes that are wavelength specific. Albedo of metal surfaces has been investigated 13,15 on a horizontal plane. McKenzie et al 13 found an albedo of 0.18 for shiny corrugated iron, but Lester and Parisi 15 carried out a more extensive investigation.…”

“…Albedo of metal surfaces has been investigated 13,15 on a horizontal plane. McKenzie et al 13 found an albedo of 0.18 for shiny corrugated iron, but Lester and Parisi 15 carried out a more extensive investigation. The surfaces in this study consisted of metallic roof sheeting in both galvanised (zinc coated stainless steel) and colour coated stainless steel sheets with albedo measurements ranging from 0.25 to 0.32 depending on wavelength for the galvanised sheeting and 0.03 to 0.12 depending on wavelength and colour for the colour sheeting.…”