Spectral shade ratios on horizontal and sun normal surfaces for single trees and relatively cloud free sky

Parisi, Alfio V.; Kimlin, Michael G.; Turnbull, David

doi:10.1016/s1011-1344(01)00258-5

Cited by 16 publications

(9 citation statements)

References 18 publications

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“…5) or trees ( e.g. 6,7) attenuate UV radiation. Reflections from urban materials like metals, concrete or glass may enhance radiation to a small extent ( e.g.…”

Section: Introductionmentioning

confidence: 99%

UV Exposition During Typical Lifestyle Behavior in an Urban Environment

Schmalwieser

Enzi

Wallisch

et al. 2010

Photochem & Photobiology

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In this study the personal exposure to solar UV radiation in an urban environment was measured. Lifestyle in an urban environment is characterized by staying indoors during most of the day. Furthermore, the ambient UV radiation is mitigated by shadowing by buildings. The aim of the study was to find out activities which may contribute to UV-induced health risk in a low exposure environment. Exposure was measured during typical outdoor activities: shopping, walking, sitting in a sidewalk café, cycling, sightseeing and at an open-air pool (solar elevation: 10 degrees-70 degrees). Measurements were taken with an optoelectronic device which was fixed on the chest. Besides the UV Index we used the sun burn time (SBT) for risk assessments. Generalization of our results was made by calculating ratios of personal exposure to the ambient UV radiation. UV exposure was by far the highest when our study subject stayed at the swimming pool. The SBT was around 30 min for melano-compromised skin type. For all other activities, except shopping, the SBT range up to 1 h. With respect to photodamage we found that at high solar elevation (>45 degrees) photoprotective measures should be applied for certain activities even within a city.

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“…5) or trees ( e.g. 6,7) attenuate UV radiation. Reflections from urban materials like metals, concrete or glass may enhance radiation to a small extent ( e.g.…”

Section: Introductionmentioning

confidence: 99%

UV Exposition During Typical Lifestyle Behavior in an Urban Environment

Schmalwieser

Enzi

Wallisch

et al. 2010

Photochem & Photobiology

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“…The influence of the ground topography on the UV exposures was investigated for inclined planes over high albedo ground surfaces (Weihs, 2002). The UV irradiances on vertical surfaces (Webb et al, 1999) and surfaces normal to the sun have been reported (Parisi and Kimlin, 1999;McKenzie et al, 1997;Parisi et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Measured and modelled contributions to UV exposures by the albedo of surfaces in an urban environment

Parisi

Sabburg

Kimlin

et al. 2003

Theoretical and Applied Climatology

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1 SummaryThe increases in the erythemal UV exposures to horizontal planes and to inclined planes over three surfaces that are found in an urban environment (water, concrete and sand) due to the albedo of these surfaces have been estimated. For the cloud free case, the additional daily estimated UV exposures to a horizontal plane have a maximum value of 222 (J m -2 ) ER , where the index after the unit is there to indicate that it refers to a biologically effective exposure. In comparison, the daily erythemal UV exposures over a year to a horizontal plane ranged from 425 to 8,321 (J m -2 ) ER . For a vertical receiving plane that is rotating about a vertical axis, the additional erythemal daily UV exposures for the sub-tropical latitude location of this research for the ranges of solar azimuth angles encountered over the days in each season ranged from 16 to 311 (J m -2 ) ER , 29 to 566 (J m -2 ) ER and 46 to 905 (J m -2 ) ER for water, concrete and sand respectively. The estimated error is ±20% and the calculations are based on clear-sky conditions. The additional erythemal UV averaged over each of the seasons was higher for the receiving plane inclined at 45 o below the horizontal plane. In a similar fashion, the vertical surface has the higher additional erythemal UV exposures compared to the surfaces inclined at an angle above the horizontal.2

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“…Studies on the levels of UV observed in the shade of different shade environments have shown that the relative proportions of UVA and UVB in the shade are significantly different to those in full sun (Turnbull et al, 2005;Parisi et al, 2001). The relative proportions of the UVA in shade to those in full sun are decreased compared to the relative proportions of the UVB in shade to those in full sun.…”

Section: Discussionmentioning

confidence: 99%

Utilising shade to optimize UV exposure for vitamin D

Turnbull

Parisi

2008

Atmos. Chem. Phys.

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Abstract. Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D 3 . The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D 3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D 3 effective UV exposures (UV D 3 ). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4 • to 80 • at a latitude of 27.6 • S. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50 • can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40 • , the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UV D 3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UV D 3 (290-315 nm) radiation without experiencing the high levels of UVA observed in full sun.

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Spectral shade ratios on horizontal and sun normal surfaces for single trees and relatively cloud free sky

Abstract: Abstract

Cited by 16 publications

References 18 publications

UV Exposition During Typical Lifestyle Behavior in an Urban Environment

UV Exposition During Typical Lifestyle Behavior in an Urban Environment

Measured and modelled contributions to UV exposures by the albedo of surfaces in an urban environment

Utilising shade to optimize UV exposure for vitamin D

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