Carol Moogk-Soulis — Schoolyard Heat Islands: A Case Study in the City of Waterloo Recap by Janet Ozaruk and Michael Frind Carol Moogk-Soulis’s interest in the concept of heat islands was sparked when her child first began attending school. She found that during recess the youngsters were not playing the active games that she remembered from her youth, but were instead seeking shelter against the school building, away from the hot and dusty playground. This observation turned into a concern regarding the lack of play and its possible resulting impacts on children’s development. Looking into the possibility of planting a few trees in the school yard, Carol found no policies regarding the incorporation of trees into schoolyard design, nor for the care of such trees. This led to the determination to quantify the benefits of trees and justify the planting of them in schoolyards. To identify and quantify heat islands, Carol turned to NASA-developed satellite technology. The satellite images provided a quantifiable thermal band and provided a better indicator than thermal sensors buried in the soil. Focussing on imagery of Waterloo, land types were classified into the following categories: high density urban, low density urban, grassland, cropland, forest, and water. A temperature profile of the area was then developed in cross-section. It was found that surface temperature readings taken during the morning recess period averaged 47C for urban areas, while the temperature of the 15 schoolyards examined ranged from 48.4C to 55C. The excessive heat associated with the schoolyards could be attributed to three factors: the steel/tar and chip roofs; the mowed turf-grass; and the asphalted parking lots, play areas, and portable classroom pads. Carol chose Mary Johnson Public School for further study. Subsequent temperature sampling taken during the morning recess in indicated an air temperature of 27C at the University of Waterloo weather station, a shaded surface temperature at Mary Johnson School of 32C, and a near-surface (head level of the average child) temperature of 43C at the school. It was also noted that the lack of shade affected the air conditioning utilities bill, as the air intakes located on the building roof drew in superheated air for cooling. On occasion, portables needed to be abandoned as they were too hot inside to conduct classes. Neighbouring houses were also affected. An examination of temperature profiles across the area indicated that the heat conducted from the schoolyard was still felt 150 m away. Clearly, if the heat-island effects around the schoolyards could be reduced, a reduction in both urban heat and smog levels would result. Mitigation of the heat island effect could be accomplished in two ways: increase heat reflection through appropriate building materials (which not always possible in existing buildings and yards), and increase shade to prevent the sun from striking the surface in the first place. The benefits of planting shade trees throughout schoolyards include a decrease in shaded surface temperatures of up to 25C, a decrease in shaded air temperatures of up to 10C, a decrease in cooling costs associated with building operation, a decrease in radiant and convective heat gains to neighbouring properties up to 80 metres distant, and contribution to overall city cooling by 0.15C. In 1990, various plantings were carried out in the Mary Johnson schoolyard, with the emphasis on creating a habitat link between woodlots. The trees have since matured to provide a welcoming environment; however, temperature calculations have not been conducted due to a lack of more recent satellite imagery of the area. It was noted that the resources in terms of trees and labour are available to turn a hostile schoolyard environment into one that encourages play and active learning. In spite of this, policies are still needed to protect all of our urban trees. Carol’s background incorporates both occupational therapy and engineering. She is continuing her research on the heat-island theme by attempting to correlate negative behaviour at schools with increased environmental temperatures, and also to correlate carbon dioxide levels in schools with heat levels and how they relate to academic performance. (A detailed write-up of her findings is available in the proceedings from the Canadian Urban Forest Conference, Markham 2002.) Thanks to Carol Moogk-Soulis for an eye-opening investigation into an often-overlooked aspect of our urban environment.
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