Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that adding more trees and parks to city centers can reduce local temperatures by up to 4 degrees Celsius during summer heatwaves. Interestingly, the effect was strongest in areas with tall buildings, because trees provided shade and released moisture through transpiration. The study also noted that residents living within 500 meters of a green space reported better mental health, but the temperature benefit was only observed when green spaces covered at least 30% of the neighborhood. So, it's not just about having a few plants; the density matters.
❓ According to the lecture, what condition is necessary for green spaces to reduce local temperatures?
A. A. They must be located near tall buildings.
B. B. They should cover at least 30% of the neighborhood.
C. C. They need to include both trees and parks.
D. D. They must be within 500 meters of residential areas.
✅ 正确答案
B. They should cover at least 30% of the neighborhood.