Cooling the Heat Island in Compact Urban Environments: The Effectiveness of Chicago's Green Alley Program

AbstractTo build 21st century sustainable cities, officials are installing alternative infrastructure technologies to reduce atmospheric environmental problems such as the urban heat island (UHI). The purpose of this study is to further our understanding of how ground-level UHI mitigation strategies in compact urban areas impact air temperatures. The term ‘cool pavement’ refers to both reflective and porous pavements. While cool pavements are identified as UHI mitigation strategies, we evaluated their in-situ effectiveness on air and surface temperatures. Using a case-control research design, we measured the impact of these pavements on air temperature relative to conventional asphalt in alleys. In locations where high vertical walls constrained the release of solar radiation, reflective pavements increased air temperatures. In two neighborhoods, reflective concrete increased daytime 3-meter air temperatures by 0.9° C and 0.5° C respectively and had no influence on nighttime temperatures. Unlike reflective pavement, porous pavements permit percolation and may contribute to cooling through evaporation. However, our research illustrated that porous asphalt and porous concrete increased maximum daytime air temperatures by 0.8° C and 0.5° C and did not lower nighttime air temperatures. While porous concrete pavers had significantly warmer midday air temperatures, it was the only cool pavement strategy to yield lower early evening air temperatures relative to conventional asphalt. Even immediately after rain events, the air temperatures above the porous pavements were not significantly cooler. This research demonstrates our need to evaluate real world installations of cool pavement to determine their actual impact on decreasing summertime temperatures

Evaluating Neighborhood Environments for Urban Heat Island Analysis and Reduction.

City officials are increasingly concerned about heat. Two warming processes are increasing the occurrence of urban heat: 1) global warming caused by greenhouse gas emissions and 2) intensifying urban heat islands (UHI) caused by urbanization. Global climate change increases the frequency, intensity, and duration of hot days. UHIs result in warmer urban air temperatures relative to rural and suburban areas Problems directly resulting from hot weather and UHIs include increased heat mortality, infrastructure failure, increased stress to vegetation, and decreased air and water quality. City officials are increasingly taking action to analyze and reduce UHIs. Yet, past research provides insufficient information for researchers and planners on 1) the relative contribution of neighborhood physical characteristics to UHIs and how those physical characteristics’ contribution may change during different times of day, 2) the accuracy of land cover quantification necessary to predict UHIs, and 3)monitoring the performance of in-situ cool pavement strategies. To address these gaps in the literature, I conducted three related studies of UHIs in eight Chicago neighborhoods in 2010. 1) I found that light winds at night resulted in stronger relationships between independent neighborhood physical variables and UHI intensity (2 a.m., adjusted R2 = 0.68) than during the afternoon (4 p.m., adjusted R2 = 0.26). At night land cover variables were better predictors of UHIs relative to other factors. Yet, during the afternoon, I found that upwind heat sources were better predictors of UHIs relative to other factors. 2) In the second study, I found that coarse (two-dimensional) quantification of impervious surface area are sufficient for UHI prediction. Even so, more detailed (three-dimensional) quantification that document impervious surfaces concealed by tree canopy are likely better for urban forestry and planning for rights-of-way. 3) Finally, I found that out of six different cool pavement strategies, highly reflective concrete and pervious concrete, cooled the air. Both designs had cooler air at three meters by at least -0.40⁰C compared to conventional asphalt paving. As city officials move to implement initiatives to reduce UHIs, this research provides a useful direction on how to conduct UHI analysis and monitor the performance of UHI reduction strategies.PHDUrban and Regional PlanningUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/97983/1/pcoseo_1.pd

Hermes & the Euexia: A Note on Nudity, Youth & Divinity in the Gymnasium

Pendant la fête annuelle des Hermaia, des jeunes gens participaient, dans le gymnase, à l’euexia, un concours de beauté et de forme du corps nu. Dans le cadre de cette fête d’Hermès, l’euexia célèbre les aspects et des caractéristiques qui sont importants aussi bien pour le gymnase que pour son patron divin. Tout comme le corps sain et beau est un signe de vertu civique, le processus par lequel il est atteint est inspiré par Hermès : pendant le temps éphémère de la jeunesse, les athlètes cherchent la reconnaissance dans les concours du gymnase. Euexia ou la bonne constitution physique est étroitement liée à l’idée de l’effort physique, à l’image mythique d’Hermès constituée par les actions, les aspects et les attributs du dieu, opérant dans d’autres domaines.During the annual festival of the Hermaia, participants in the gymnasium competed in the euexia, a contest judging the beauty and form of the naked body. As part of the annual festival to Hermes, the euexia celebrated aspects and attributes important both to the gymnasium and to its patron deity. Just as the fit and beautiful body was a sign of civic virtue, the process by which it was attained was inspired by Hermes: in the evanescent period of youth, gymnasts strove for recognition in the contests of the gymnasium. Euexia or physical fitness was closely bound with the idea of exertion and physical effort, mirroring the mythic strivings of Hermes as expressed in a set of actions, aspects, and attributes of the god at work in other fields

Urban Park Systems to Support Sustainability: The Role of Urban Park Systems in Hot Arid Urban Climates

Quantifying ecosystem services in urban areas is complex. However, existing ecosystem service typologies and ecosystem modeling can provide a means towards understanding some key biophysical links between urban forests and ecosystem services. This project addresses broader concepts of sustainability by assessing the urban park system in Phoenix, Arizona’s hot urban climate. This project aims to quantify and demonstrate the multiple ecosystem services provided by Phoenix’s green infrastructure (i.e., urban park system), including its air pollution removal values, carbon sequestration and storage, avoided runoff, structural value, and the energy savings it provides for city residents. Modeling of ecosystem services of the urban park system revealed around 517,000 trees within the system, representing a 7.20% tree cover. These trees remove about 3630 tons (t) of carbon (at an associated value of $285,000) and about 272 t of air pollutants (at an associated value of$1.16 million) every year. Trees within Phoenix’s urban park system are estimated to reduce annual residential energy costs by $106,000 and their structural value is estimated at$692 million. The findings of this research will increase our knowledge of the value of green infrastructure services provided by different types of urban vegetation and assist in the future design, planning and management of green infrastructure in cities. Thus, this study has implications for both policy and practice, contributing to a better understanding of the multiple benefits of green infrastructure and improving the design of green spaces in hot arid urban climates around the globe

Public transit infrastructure and heat perceptions in hot and dry climates

Many cities aim to progress toward their sustainability and public health goals by increasing use of their public transit systems. However, without adequate protective infrastructure that provides thermally comfortable conditions for public transit riders, it can be challenging to reach these goals in hot climates. We took micrometeorological measurements and surveyed riders about their perceptions of heat and heat-coping behaviors at bus stops with a variety of design attributes in Phoenix, AZ, USA, during the summer of 2018. We identified the design attributes and coping behaviors that made riders feel cooler. We observed that current infrastructure standards and material choices for bus stops in Phoenix are insufficient to provide thermal comfort, and can even expose riders to health risks. Almost half of the study participants felt hot or very hot at the time they were surveyed, and more than half reported feeling thermally uncomfortable. On average, shade reduced the physiological equivalent temperature (PET) by 19 °C. Moreover, we found significant diurnal differences in PET reductions from the shade provided by various design attributes. For instance, all design attributes were effective in reducing PET in the morning; however, a vegetated awning did not provide statistically significant shade reductions in the afternoon. Temperatures of sun-exposed surfaces of man-made materials exceeded skin burn thresholds in the afternoon, but shade was effective in bringing the same surfaces to safe levels. Aesthetically pleasing stops were rated as cooler than stops rated as less beautiful. We conclude that cities striving to increase public transit use should prioritize thermal comfort when designing public transit stops in hot climates. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00484-021-02074-4

Detection of enzyme polymorphism by using monoclonal antibodies.

Six monoclonal antibodies against human placental alkaline phosphate [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1], a highly polymorphic enzyme, were tested for reactivity against a panel of 295 placental extracts that had been typed electrophoretically. The products of the three common alleles as well as several rare alleles could be discriminated by the various antibodies. In some cases differences between allelic products were reflected by essentially "all-or-none" reactions, but in other cases the differences were smaller and demonstrable only by quantitative analysis of the binding. Evidence for allelic differences not detectable electrophoretically was also obtained