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Published byReynold Stevens Modified over 9 years ago
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Heat Islands
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Heat Islands are created by the unique thermal characteristics in urban areas
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Heat Islands The average temperature of a city is typically slightly higher than that of the surrounding countryside. Some days the city temperature may be as much as 10 o C higher. This “island” of warmer temperatures is called a heat island. The Island idea suggests an isolated environment - one that is segregated from the surroundings
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Heat Island intensity in Atlanta: Hotlanta
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Why we should care about heat island effects… 1/6th of total electricity consumed in the U.S. is used for cooling, costing $40 billion per year. Also remember that electricity generates CO 2 Air quality studies in Los Angeles estimate that a 1° F increase in summer temperatures boosts smog formation by 3%. Increase in Ozone levels Students often confuse good versus bad ozone HOW the land is used can help reduce the temperature
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Why temperature and Ozone are connected
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Ground Level Ozone Formation Ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOC) react with sunlight. NOx is a by-product of high- temperature combustion created by automobiles and power plants. VOCs include organic chemicals that vaporize easily, such as gasoline.
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Ozone: The Bad and the Ugly Ozone reacts with the C=C double bonds and breaks down the molecule into very reactive radicals. These radicals then react further. The end result is inflammation of the lungs. O 3 irritates the respiratory tract and eyes. Exposure to high levels of O 3 results in chest tightness, coughing and wheezing. People with respiratory and heart problems are at a higher risk. Ozone has been linked to increased hospital admissions.
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Impact: Weather
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The Good…? From NASA city climates have a noticeable influence on plant growing seasons up to 10 kilometers (6 miles) away from a city's edges. Growing seasons in 70 cities in eastern North America were about 15 days longer in urban areas compared to rural areas outside of a city's influence that for every 1 degree Celsius (C) or 1.8 Fahrenheit (F) that temperatures rose on average during the early springtime, vegetation bloomed 3 days earlier
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