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Heat Islands. Heat Islands are created by the unique thermal characteristics in urban areas.

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Presentation on theme: "Heat Islands. Heat Islands are created by the unique thermal characteristics in urban areas."— Presentation transcript:

1 Heat Islands

2 Heat Islands are created by the unique thermal characteristics in urban areas

3 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

4 Heat Island intensity in Atlanta: Hotlanta

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6 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

7 Why temperature and Ozone are connected

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9 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.

10 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.

11 Impact: Weather

12 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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