Today in our environmental science lecture, we'll discuss urban green spaces. Recent studies show that city parks not only improve air quality but also reduce stress levels among residents. For example, a survey in Melbourne found that people living within 500 meters of a park reported 20% lower anxiety. However, the key factor is accessibility, not just presence. A park surrounded by busy roads is less used. Therefore, planners should prioritize connected networks of small green areas over a single large one. This approach encourages daily walking and social interaction.