In towns and cities in addition to parks and open spaces, rooftop gardens can be an effective means to improve the quality of life, through air cooling and filtering.
While most cities around the world lack green areas, especially in the inner city, all have unused rooftops that could be turned into gardens with major environmental, health and social benefits.
By promoting and supporting rooftop gardens in new and refurbished buildings, city authorities could achieve several important results:

• Improvement of city climate: through transpiration and evaporation plants cool the air, lowering its temperature, and reduce urban heat.
• Improvement of air quality: plants absorb particulate matter and other pollutants and thereby contribute to reducing health problems.
• Precipitation control: plants reduce and slow down rainwater runoff. The water stored in the installation can be released into the atmosphere via evaporation or possibly reused to water plants.
• Energy savings: rooftops gardens avoid overheating of surfaces and reduce air conditioning costs.
• Increased roof life: rooftop gardens protect roofs from premature ageing.
• Increased biodiversity: an increase in the variety of plants sustains birdlife and offers shelter to small animals.
• More green spaces: rooftop gardens create new meeting points and provide space for urban kitchen gardens.