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In summer, urban heat islands increase building cooling demands, aggravate air pollution, and cause heat-related illnesses. As a mitigation strategy, reflective cool pavements have been deemed an effective measure to decrease the temperature in urban areas. However, the reflection of paved streets in an urban area will be different from that in an...
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Context 1
... skin temperatures at different places in the gray streets w than 2 °C at solar noon ( Figure 3). As indicated in Figure 3, the temp different place to place, but a closer look found that the highest temp imately 49 °C, while the lowest temperature was close to 47 °C. ...
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... skin temperatures at different places in the gray streets w than 2 °C at solar noon ( Figure 3). As indicated in Figure 3, the temp different place to place, but a closer look found that the highest temp imately 49 °C, while the lowest temperature was close to 47 °C. The m was about 2 °C. ...
Context 3
... skin temperatures at different places in the gray streets were different by less than 2 • C at solar noon ( Figure 3). As indicated in Figure 3, the temperature contour was different place to place, but a closer look found that the highest temperature was approximately 49 • C, while the lowest temperature was close to 47 • C. The maximum difference was about 2 • C. As a result, there are some small difference at temperature contours across the street, possibly because of the measurement error of the thermocouple sensors. ...
Context 4
... skin temperatures at different places in the gray streets were different by less than 2 • C at solar noon ( Figure 3). As indicated in Figure 3, the temperature contour was different place to place, but a closer look found that the highest temperature was approximately 49 • C, while the lowest temperature was close to 47 • C. The maximum difference was about 2 • C. As a result, there are some small difference at temperature contours across the street, possibly because of the measurement error of the thermocouple sensors. The small difference in the skin temperature is because at solar noon, the sun is right above the urban street so the solar irradiance on the street is similar. ...
Citations
... Previous studies (Srivanit & Jareemit 2020;Kotopouleas et al. 2021;Tochaiwat et al., 2023) have explored the benefits of shading in hot-humid climates through increasing the ratio of building height to street width (H/W), planting trees along streets, and using varying building orientations. It has been found that the impact of cool pavements in terms of a reduction in air temperature in shaded areas is not significant due to the shade protect surface pavement directly exposed to the solar heat resulting in less heat absorption (Schrijvers et al. 2016;Nasrollahi et al. 2020;Zhang et al. 2021). ...
... In areas with limited shade, and particularly on streets oriented along the E-W direction and exposed to solar radiation throughout the day, it is important to consider the urban surface albedo as a significant factor in mitigating UHI and thermal stress, as noted by Srivanit and Jareemit (2020), Zhang et al. (2021), and Takebayashi and Moriyama (2012b). Increasing the surface albedo can prevent excessive heat absorption, and can promote a more comfortable outdoor environment (Greater London Authority 2006; Oke et al.2017;Ford & Ford 2000;Erell et al. 2014;Mohammad et al. 2021). ...
... Due to issues related to global warming, the problem of heat-related deaths arising from increases in urban temperature has become a significant concern in terms of outdoor activities. Improving the thermal conditions for pedestrians in E-W street canyons poses a challenge, as there is little shade from buildings, especially in street canyons with low H/W ratios (Srivanit & Jareemit 2020; Zhang et al. 2021;Takebayashi & Moriyama 2012a). In this study, we investigated several combinations of paving and wall surfaces with various surface albedos to find the potential reductions in air temperature and heat stress mitigation in street canyons with limited surrounding shade under extreme conditions. ...
... Urban green spaces play an important role in temperature control through decrease in sensible heat that raises temperature by increasing latent heat, and crown shadows reducing the inflow of solar radiation (Armson, Stringer & Ennos, 2012;Block, Livesley & Williams, 2012;Doick & Hutchings, 2013;Konarska et al., 2016). In terms of the direction of the street, shadow is not formed on the sidewalk located on the northern side of the East-West street, so it is generally more vulnerable than the North-South street owing to continuous exposure time from irradiance during the day (Achour--Younsi & Kharrat, 2016;Zhang, Wei, Wang & Qin, 2021). Therefore, to improve the thermal environment efficiently, it is necessary to reliably evaluate the current thermal environment and key factors, and to have a simulator that can quickly evaluate according to urban structure and cooling strategies. ...
... 23 articles were concerned with at-grade or ground surface impacts of linear infrastructure on the UHI (Fox, 1988). At-grade infrastructures can be enclosed by facades (buildings) and pavements (contributing to UHI SURF ), are the conduits for a great number of vehicles, and have the greatest potential to contribute to increased Ta in UCL and so UHI UCL (Zhang et al., 2021b). Urban ventilation and energy balance were identified as the most important contributing factors to UHI. ...
Urbanisation is a global trend resulting in more people living in cities. This has led to changes in urban morphology and microclimates explained by the urban heat island (UHI) effect. The UHI effect has been differentiated into four typologies that relate to the subsurface, surface, canyon and boundary influences. This paper presents a systematic literature review that explores the specific contribution of urban linear infrastructure (ULI), inclusive of the road network (flyovers, at-grade, and underground transport), rail (heavy and light) systems and utility corridors (pipe and electricity networks) to the UHI effect. 288 papers were identified within which urban linear infrastructure has been examined with respect to the UHI effect. The review reveals gaps in the research of the UHI with reference to how linear transport corridors influence the urban climate. Given the different forms of transport corridors, underground, at grade and flyovers, scales and locations, their effect on microclimates can be represented by a dynamic interaction of to the four UHI typologies. Given this complexity, this review provides evidence for researchers, urban planners, climatologists, and transport planners to more fully consider the role that urban linear infrastructure systems have on urban climates.
... Most of the cool pavement impact studies to date are based on numerical modeling, using either mesoscale climate models [24,31,35] or micrometeorological computational fluid dynamics models [23,32,33,[48][49][50][51][52][53][54][55][56][57][58][59][60]. A number of studies have studied the thermal performance of cool pavement segments in laboratory or controlled field measurement settings, but these studies did not investigate the direct impacts on the urban environment [61][62][63][64][65][66][67]. One modeling study [68] used an indoor-outdoor coupled building energy model to study the effects of cool pavements on building energy use. ...
Climate change is expected to exacerbate the urban heat island effect in cities worldwide, increasing the risk of heat-related morbidity and mortality. Solar reflective “cool pavement” is one of several mitigation strategies that may counteract the negative effects of the urban heat island effect. An increase in pavement albedo results in less heat absorption, which results in reduced surface temperatures (T surface ). Near surface air temperatures (T air ) could also be reduced if cool pavements are deployed at sufficiently large spatial scales, though this has never been confirmed by field measurements. This field study is the first to conduct controlled measurements of the impacts of neighborhood-scale cool pavement installations. We measured the impacts of cool pavement on albedo, T surface , and T air . In addition, pavement albedo was monitored after installation to assess its degradation over time. The field site (~0.64 km2) was located in Covina, California; ~30 km east of Downtown Los Angeles. We found that an average pavement albedo increase of 0.18 (from 0.08 to 0.26) corresponded to maximum neighborhood averaged T surface and T air reductions of 5 °C and 0.2 °C, respectively. Maximum T surface reductions were observed in the afternoon, while minimum reductions of 0.9 °C were observed in the morning. T air reductions were detected at 12:00 local standard time (LST), and from 20:00 LST to 22:59 LST, suggesting that cool pavement decreases T air during the daytime as well as in the evening. An average albedo reduction of 30% corresponded to a ~1 °C reduction in the T surface cooling efficacy. Although we present here the first measured T air reductions due to cool pavement, we emphasize that the tradeoffs between T air reductions and reflected shortwave radiation increases are still unclear and warrant further investigation in order to holistically assess the efficacy of cool pavements, especially with regards to pedestrian thermal comfort.
... Urban green spaces play an important role in temperature control through decrease in sensible heat that raises temperature by increasing latent heat, and crown shadows reducing the inflow of solar radiation (Armson, Stringer & Ennos, 2012;Block, Livesley & Williams, 2012;Doick & Hutchings, 2013;Konarska et al., 2016). In terms of the direction of the street, shadow is not formed on the sidewalk located on the northern side of the East-West street, so it is generally more vulnerable than the North-South street owing to continuous exposure time from irradiance during the day (Achour--Younsi & Kharrat, 2016;Zhang, Wei, Wang & Qin, 2021). Therefore, to improve the thermal environment efficiently, it is necessary to reliably evaluate the current thermal environment and key factors, and to have a simulator that can quickly evaluate according to urban structure and cooling strategies. ...
... According to Fernández-Antolín et al. [10], the knowledge development and transfer at the training level in sustainable architecture and civil engineering is urgent. Tsoka et al. [11] reviewed previous studies on the cooling potential of high-albedo pavements, and the use of reflective materials is considered as a passive mitigation strategy [12], which is highly recommended [13]. ...
The widespread use of solar-reflective concrete pavements can mitigate climatic change and urban heat islands (UHI) by cooling the pavement surfaces that are made of concrete instead of asphalt. The methodology that was followed is based on the comparison between the asphalt and concrete albedo effects in a specific application and area. In this study, we found that a reduction of temperature in the terrestrial surface, equivalent to the removal of 25–75 kgCO2/m2, could be achieved. Considering all the motorways and freeways of Spain, which is the third country in the world in km, a yearly equivalent carbon dioxide emissions reduction of 13–27 million tons could be reached. This value is quite high considering that the cement sector worldwide released about 2.9 Gigatons of carbon dioxide in 2016. Therefore, there is a positive balance in the use of concrete pavements. Furthermore, concrete is a material completely recyclable at the end of its service life and concrete pavement construction requires local resources, avoiding GHG emissions due to transport. An increase in the Spanish freeway network albedo by replacing asphalt pavements with concrete ones will improve the local climate change mitigation.
Os males associados aos extremos de calor são uma realidade, embora pouca importância seja dada ao assunto. Em parte, a falta de atenção é decorrente do desconhecimento. Outro motivo é a negligência do poder público, no que diz respeito à fiscalização, especialmente das condições laborais. Neste trabalho, os índices HUMIDEX e WBGT foram calculados para a Região Metropolitana de Sorocaba, interior paulista, com um conjunto de dados de 14 anos. Apesar de estar próximo ao leste paulista, Sorocaba não é influenciada pela brisa marítima, que poderia contribuir para amenizar o calor, pois o clima da região é caracterizado por temperaturas elevadas em vários meses do ano. A mensuração de índices bioclimáticos pode contribuir para as políticas de saúde pública de forma a reduzir a insalubridade de trabalhadores expostos ao calor excessivo e consequentemente promovendo melhora da qualidade de vida e até mesmo da produtividade, como indicam as pesquisas.
Resumo: Os males associados aos extremos de calor são uma realidade, embora pouca importância seja dada ao assunto. Em parte, a falta de atenção é decorrente do desconhecimento. Outro motivo é a negligência do poder público, no que diz respeito à fiscalização, especialmente das condições laborais. Neste trabalho, os índices HUMIDEX e WBGT foram calculados para a Região Metropolitana de Sorocaba, interior paulista, com um conjunto de dados de 14 anos. Apesar de estar próximo ao leste paulista, Sorocaba não é influenciada pela brisa marítima, que poderia contribuir para amenizar o calor, pois o clima da região é caracterizado por temperaturas elevadas em vários meses do ano. A mensuração de índices bioclimáticos pode contribuir para as políticas de saúde pública de forma a reduzir a insalubridade de trabalhadores expostos ao calor excessivo e consequentemente promovendo melhora da qualidade de vida e até mesmo da produtividade, como indicam as pesquisas. Palavras-chave: WBGT. HUMIDEX. Conforto térmico.
Abstract: Diseases associated with heat extremes are a reality, although little importance is given to this subject. In part, the lack of attention is due the unknowing. In part, the lack of care is the negligence of the authorities, regarding inspection, especially in terms of working conditions. In this work, the HUMIDEX and WBGT indices were calculated for the Metropolitan Region of Sorocaba, Sao Paulo countryside, with a 14-year dataset. Despite being close to the ocean, Sorocaba is not influenced by the sea breeze, which could contribute to alleviate the heat and its climate is characterized by high temperatures in several months of the year. The measurement of bioclimatic indices can contribute to public health policies in order to reduce the unhealthy conditions of workers exposed to excessive heat and, consequently, improve the quality of life and even productivity, as indicated by researches.
Pavements store heat, which is subsequently released into the atmosphere, heating the surrounding air. Therefore, this process contributes to climate change and global warming. For this reason, the use of high-solar-reflectance (albedo) pavements is seen as one of the potential mitigation methods for climate change. Concrete pavements have a much higher albedo than asphalt due to their light gray color compared with black pavements. Accordingly, the widespread utilization of highly reflective concrete pavements will improve local climate change mitigation. Nevertheless, concrete albedo slightly decreases over time because of weathering. Albedo and solar reflectance index (SRI) measurements were taken on actual precast concrete pavements made with different mixes. The methodology applied for this project is based on the comparison between the asphalt and concrete pavements’ reflectivity. Conventional concrete mix designs can provide cool pavements with SRI higher than 29. Replacement of black pavements by highly reflective concrete pavements appeared to be a cost-effective and easily implemented measure to combat climate change. Finally, multidisciplinary studies considering factors such as building materials’ albedo, among other mitigation measures, should be performed to provide more precise and reliable guidance to policymakers, stakeholders, decision makers and urban planners.
