Using urban canyon geometries obtained from Google Street View for atmospheric studies: Potential applications in the calculation of street level total shortwave irradiances

Carrasco-Hernandez, Roberto; Smedley, Andrew R. D.; Webb, Ann R.

doi:10.1016/j.enbuild.2014.10.001

Cited by 71 publications

(30 citation statements)

References 35 publications

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“…The largest assumption in the irradiance calculations is that of an uninterrupted sky view (e.g., standing in an open field with no horizon obstructions). Low horizon obstructions that are not casting a direct shadow on a person introduce little uncertainty, but, for city dwellers, the recommended exposure times may be insufficient in “city canyons” [ 26 ] and more open spaces like plazas or parks are preferred sites for gaining UVR exposure.…”

Section: Resultsmentioning

confidence: 99%

Meeting Vitamin D Requirements in White Caucasians at UK Latitudes: Providing a Choice

et al. 2018

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The body gains vitamin D through both oral intake (diet/supplementation) and synthesis in skin upon exposure to ultraviolet radiation (UVR). Sun exposure is the major source for most people even though sun exposure is complex and limited by climate and culture. We aimed to quantify the sun exposure required to meet vitamin D targets year-round and determine whether this can be safely achieved in a simply defined manner in the UK as an alternative to increasing vitamin D oral intake. Data from observation (sun exposure, diet, and vitamin D status) and UVR intervention studies performed with white Caucasian adults were combined with modeled all-weather UVR climatology. Daily vitamin D effective UVR doses (all-weather) were calculated across the UK based on ten-year climatology for pre-defined lunchtime exposure regimes. Calculations then determined the time necessary to spend outdoors for the body to gain sufficient vitamin D levels for year-round needs without being sunburnt under differing exposure scenarios. Results show that, in specified conditions, white Caucasians across the UK need nine minutes of daily sunlight at lunchtime from March to September for 25(OH)D levels to remain ≥25 nmol/L throughout the winter. This assumes forearms and lower legs are exposed June-August, while in the remaining, cooler months only hands and face need be exposed. Exposing only the hands and face throughout the summer does not meet requirements.

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Section: Resultsmentioning

confidence: 99%

Meeting Vitamin D Requirements in White Caucasians at UK Latitudes: Providing a Choice

et al. 2018

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“…Trees, grass lawns and awnings help to attenuate the reflected UVR (18). Few studies have measured solar UVR exposure in pedestrian areas and seating areas of restaurants in urban canyons (18)(19)(20)(21); and no such studies have been carried out in Africa. We measured the solar UVR exposure in urban canyons in Venice, Italy and Johannesburg, South Africa to determine and compare the effect of urban canyon types on resultant solar UVR exposures.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Solar Ultraviolet Radiation Exposure in Urban Canyons in Venice, Italy and Johannesburg, South Africa

Wright

Preez

Martincigh

et al. 2020

Photochem & Photobiology

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Urban environments can have high‐risk spaces that can provide excess personal sun exposure, such as urban or street canyons, and the spaces between buildings, among others. In these urban spaces, sun exposure can be high or low depending on several factors. Polysulphone film (PSF) was used to assess possible daily solar ultraviolet radiation (UVR) exposure in urban canyons in Venice, Italy and, for the first time in Africa, in Johannesburg, South Africa. The photodegradation of PSF upon solar exposure was monitored at a wavelength of 330 nm by ultraviolet‐visible spectrophotometry, and the resultant change was converted to standard erythemal dose (SED) units (1 SED = 100 J m−2). Mean daily ambient solar UVR exposure measured for Venice and Johannesburg ranged between 20–28 SED and 33–43 SED, respectively. Canyon‐located PSF exposures were lower in Venice (1–9 SED) than those in Johannesburg (9–39 SED), depending mainly on the sky view factor and orientation to the sun. There was large variation in solar UVR exposure levels in different urban canyons. These preliminary results should be bolstered with additional studies for a better understanding of excess personal exposure risk in urban areas, especially in Africa.

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“…[ 4 ] Pollution reduces incident UV radiation, and urban areas reduce the sky view factor and increase shade. [ 5 ] In a simulation study in an idealized situation (cloudless atmosphere, nonreflecting surface, typical level ozone layer thickness, and rural aerosol), for individuals with skin-type vitamin (i.e., most Indians), the duration of sunlight exposure equivalent to 1000 IU oral intake of Vitamin D has been reported to be 10–48 min (seasonally dependent) at 29° N and 10–17 min at 11.5° N (at solar noon). [ 6 ] This calculation assumed 25% skin area exposed to sunlight, and the calculation was for a flat horizontal, unshaded surface, not a mobile human body in a cityscape.…”

Section: Introductionmentioning

confidence: 99%

Duration of casual sunlight exposure necessary for adequate Vitamin D status in Indian Men

Patwardhan

Mughal

Chiplonkar

et al. 2018

Indian J Endocr Metab

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Objectives:To investigate the duration of casual sunlight ultraviolet-B (UVB) exposure required to maintain optimal Vitamin D status (25-hydroxyvitamin-D [25(OH)D]) >50 nmol/L in urban Indian men, using polysulfone (PSU) dosimeters and a sunlight exposure questionnaire.Methods:In healthy men (aged 40–60 years) from Pune (18.52° N, 73.86° E), India, serum 25(OH)D was measured using enzyme-linked immunosorbent assay. Sunlight exposure was assessed using PSU dosimeter and by questionnaire.Results:Of 160 men (48.3 ± 5.6 years), 26.8% were deficient and 40.6% had insufficient Vitamin D concentrations. A hyperbolic function for the relationship between PSU measured sunlight exposure in standard erythema dose (SED) and serum 25(OH)D concentrations (r = 0.87, P < 0.01) revealed that daily exposure of 1 SED was sufficient to maintain serum 25(OH)D concentrations over 50 nmol/L. The curve plateaued around 5 SED (80 nmol/L) and extrapolation of the curve (>5 SED) did not increase 25(OH)D concentrations above 90 nmol/L. Receiver operating curve analysis confirmed that 1 SED-UV exposure was sufficient to maintain 25(OH)D concentrations over 50 nmol/L. Based on the questionnaire data, >1 h of midday casual sunlight exposure was required to maintain serum 25(OH)D concentrations above 50 nmol/L. Duration of sunlight exposure assessed by questionnaire and PSU dosimeter showed a significant correlation (r = 0.517, P < 0.01).Conclusion:In urban Indian men, >1 h of casual midday sunlight exposure daily was required to maintain serum 25(OH)D concentrations above 50 nmol/L, and >2 h of casual sunlight exposure was needed to maintain 25(OH)D concentrations above 75 nmol/L. Excess sunlight did not increase 25(OH)D linearly. The sunlight exposure questionnaire was validated for use in clinical studies and surveys.

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Using urban canyon geometries obtained from Google Street View for atmospheric studies: Potential applications in the calculation of street level total shortwave irradiances

Cited by 71 publications

References 35 publications

Meeting Vitamin D Requirements in White Caucasians at UK Latitudes: Providing a Choice

Meeting Vitamin D Requirements in White Caucasians at UK Latitudes: Providing a Choice

A Comparison of Solar Ultraviolet Radiation Exposure in Urban Canyons in Venice, Italy and Johannesburg, South Africa

Duration of casual sunlight exposure necessary for adequate Vitamin D status in Indian Men

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