Nghe TOEFL

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Listen to part of a lecture in an environmental science class. The professor is discussing the concept of 'urban heat islands'. 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 materials like concrete and asphalt absorb and retain heat from the sun during the day and release it slowly at night. In contrast, rural areas with vegetation and soil tend to cool down faster. The temperature difference can be as much as 5 to 10 degrees Celsius. But why should we care? Well, higher temperatures in cities increase energy consumption for air conditioning, which in turn raises greenhouse gas emissions. Also, heat islands can worsen air pollution and pose health risks, especially for vulnerable populations like the elderly. Several mitigation strategies exist, such as planting more trees, creating green roofs, and using reflective materials on buildings. These measures not only cool the city but also improve overall quality of life.'