Urban heat island and wind flow characteristics of a tropical city

Rajagopalan, Priyadarsini; Lim, Kee Chuan; Jamei, Elmira

doi:10.1016/j.solener.2014.05.042

Cited by 200 publications

(89 citation statements)

References 55 publications

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“…Some UHIs can be as high as 8 • C, e.g., in tropical regions [14,15], but this is rather atypical. More often, UHIs are in the order of 0.5 to 3 • C [8].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Urban Heat and Exacerbation: Development of a Heat Island Index for California

Taha¹

2017

Climate

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Abstract:To further evaluate the factors influencing public heat and air-quality health, a characterization of how urban areas affect the thermal environment, particularly in terms of the air temperature, is necessary. To assist public health agencies in ranking urban areas in terms of heat stress and developing mitigation plans or allocating various resources, this study characterized urban heat in California and quantified an urban heat island index (UHII) at the census-tract level (~1 km 2 ). Multi-scale atmospheric modeling was carried out and a practical UHII definition was developed. The UHII was diagnosed with different metrics and its spatial patterns were characterized for small, large, urban-climate archipelago, inland, and coastal areas. It was found that within each region, wide ranges of urban heat and UHII exist. At the lower end of the scale (in smaller urban areas), the UHII reaches up to 20 degree-hours per day (DH/day; • C.hr/day), whereas at the higher end (in larger areas), it reaches up to 125 DH/day or greater. The average largest temperature difference (urban heat island) within each region ranges from 0.5-1.0 • C in smaller areas to up to 5 • C or more at the higher end, such as in urban-climate archipelagos. Furthermore, urban heat is exacerbated during warmer weather and that, in turn, can worsen the health impacts of heat events presently and in the future, for which it is expected that both the frequency and duration of heat waves will increase.

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“…Some UHIs can be as high as 8 • C, e.g., in tropical regions [14,15], but this is rather atypical. More often, UHIs are in the order of 0.5 to 3 • C [8].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Urban Heat and Exacerbation: Development of a Heat Island Index for California

Taha¹

2017

Climate

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“…The studies of thermal comfort have been examined in a variety of environments, such as an indoor environment [6,9,10], housing blocks [11], outdoor apartment blocks [12], a street canyon [13][14][15], and university campus [16][17][18][19] and Xi et al [20], city center [21]. Personal factors are more concerned with people's perception of thermal comfort in outdoor environment collected through surveys [22,23].…”

Section: Introductionmentioning

confidence: 99%

Modeling Thermal Comfort and Optimizing Local Renewal Strategies—A Case Study of Dazhimen Neighborhood in Wuhan City

et al. 2015

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Abstract:Modeling thermal comfort provides quantitative evidence and parameters for effective and efficient urban planning, design, and building construction particularly in a dense and narrow inner city, which has become one of many concerns for sustainable urban development. This paper aims to develop geometric and mathematical models of wind and thermal comfort and use them to examine the impacts of six small-scale renewal strategies on the wind and thermal environment at pedestrian level in Dazhimen neighborhood, Wuhan, which is a typical case study of urban renewal project in a mega-city. The key parameters such as the solar radiation, natural convection, relative humidity, ambient crosswind have been incorporated into the mathematical models by using user-defined-function (UDF) method. Detailed temperature and velocity distributions under different strategies have been compared for the optimization of local renewal strategies. It is concluded that five rules generated from the simulation results can provide guidance for building demolition and OPEN ACCESSSustainability 2015, 7 3110 reconstruction in a neighborhood and there is no need of large-scale demolition. Particularly, combining the local demolition and city virescence can both improve the air ventilation and decrease the temperature level in the study area.

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“…This discrepancy can be attributed to the distance between the meteorological station and pollution sampling toll plazas, and the landscape known to obstruct airflow and effective weather observation [50]. Also, variations in land use/cover have been found to impact micro-climatic conditions [51] [52], suggesting that the weather conditions at toll plazas could differ from those observed at the meteorological stations. Similar inconsistencies were disclosed by Tsai [4], where wind speed, humidity and temperature relationships with Polycyclic Aromatic Hydrocarbons (PAHs) were not statistically significant.…”

Section: T Ekeu-wei Et Almentioning

confidence: 99%

Passive Sampling of Ambient Nitrogen Dioxide at Toll Plazas in Malaysia

Ekeu-wei¹,

Azuma²,

Ogunmuyiwa³

2018

OJAP

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With the increasing trend of development and industrialization in Malaysia, air pollution has become an inevitable part of the process, resulting from increased vehicular activities and industrial processes. Toll operators are potentially exposed to high levels of air pollutants from working in proximity to traffic pollution sources, thereby increasing their risk of health defects associated with air pollution exposure. This study assessed the levels of Nitrogen dioxide (NO 2 ) toll operators are exposed to, considering the influences traffic density and meteorological factors. This is intended to serve as an indicator of the cumulative pollution emanating from the combustion process of vehicles at toll plazas. Using Passive diffusion samplers saturated with Triethanolamine (TEA), the weekly indoor and outdoor NO 2 concentrations at tollbooth were measured at Sungai Besi (SB), Kajang (KJ) and Putra-Makhota (PM) toll Plazas, to capture the varying traffic densities of 138,000, 65,000 and 24,100 vehicles/day respectively. The results showed that NO 2 concentrations increase with traffic densities, and indoor NO 2 concentrations correlated highly with outdoor NO 2 concentrations (R 2 : SB = 0.767, KJ = 0.689 and PM = 0.877). The indoor/outdoor NO 2 ratio varied from 0.7 to 1.2 for all toll booths, suggesting pollution control in-efficiency, caused by technical and behavioural factors. Also, meteorological factors had no significant effect on nitrogen dioxide concentrations, contrary to previous studies, which is likely due to the far distance between tool plazas and meteorological stations. Furthermore, the NO 2 concentrations reported in this study were higher in comparison to weekly standards adopted in Germany (0.032 ppm) and previous literature. Therefore, toll operators are potentially exposed to high levels of pollution, and we advise that toll operators to wear pollution protection gears to reduce the risk of exposure, and the ventilation systems and mitigation measure (air curtain) reviewed to assess its efficiency.

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Urban heat island and wind flow characteristics of a tropical city

Cited by 200 publications

References 55 publications

Characterization of Urban Heat and Exacerbation: Development of a Heat Island Index for California

Characterization of Urban Heat and Exacerbation: Development of a Heat Island Index for California

Modeling Thermal Comfort and Optimizing Local Renewal Strategies—A Case Study of Dazhimen Neighborhood in Wuhan City

Passive Sampling of Ambient Nitrogen Dioxide at Toll Plazas in Malaysia

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