Yes, rooftop gardens and green roofs can indeed help mitigate urban heat island effects and improve air quality. These green spaces can absorb and retain heat, reducing the overall temperature in urban areas. They also help to filter pollutants from the air, leading to cleaner and healthier air quality for city residents. Additionally, rooftop gardens can provide habitats for wildlife, reduce energy consumption by providing insulation, and create a more aesthetically pleasing environment in urban settings.