การฟัง TOEFL

🎧 บทถอดเสียง

Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. This happens because concrete, asphalt, and buildings absorb and re-emit heat more than natural landscapes like forests or fields. Also, human activities—such as driving cars and running air conditioners—generate waste heat. The temperature difference can be as much as 5 to 10 degrees Fahrenheit on clear, calm nights. This extra heat has real consequences: it increases energy consumption for cooling, raises air pollution levels, and can even lead to heat-related illnesses. But there are solutions. Planting trees and creating green roofs—roofs covered with vegetation—can provide shade and cool the air through evapotranspiration. Using reflective materials on roofs and pavements also helps. In fact, cities like Los Angeles have implemented cool roof programs. So, while urban heat islands are a serious issue, they're not inevitable. With thoughtful design, we can make our cities more comfortable and sustainable.