การฟัง TOEFL

🎧 บทถอดเสียง

Listen to part of a lecture in an environmental science class. Professor: Today we're discussing urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. The main cause is the replacement of natural surfaces with materials like concrete and asphalt, which absorb and re-radiate heat. Additionally, human activities, such as running cars and air conditioners, generate waste heat. One surprising factor is the lack of vegetation. Trees and green spaces provide shade and release moisture through evapotranspiration, which cools the air. In cities, this cooling effect is reduced. To combat this, some cities are implementing green roofs—covering rooftops with plants—which can lower building temperatures and reduce energy use. Another strategy is using reflective materials for pavements. These solutions not only mitigate heat but also improve air quality. However, they require initial investment and maintenance. So, while the problem is serious, there are practical steps we can take.