Which measure helps reduce the heat island effect in a city or campus?

• A. Increase building height
• B. Increase dark asphalt
• C. Remove trees
• D. Reflective roofing

Answer: (D)

Reducing the urban heat island effect hinges on limiting how much heat solar energy is absorbed by urban surfaces. Reflective roofing increases the albedo of roof surfaces, meaning more sunlight is reflected rather than absorbed. When roofs stay cooler because they reflect heat, buildings demand less cooling, and the surrounding air stays closer to outdoor temperatures, helping overall urban temperatures be lower. Increasing building height doesn’t specifically reduce heat absorption and can alter wind and shade patterns in ways that don’t address heat gain. Dark asphalt absorbs a lot of solar energy, making surfaces hotter and contributing to higher temperatures in the area. Removing trees eliminates shade and the cooling effect of evapotranspiration, which would worsen heat buildup. So using reflective, cool roofing is the most effective option among these for mitigating heat island effects.