Green roofs help clean the air by trapping airborne particles and absorbing gaseous pollutants.
Here's a more detailed explanation:
Mechanisms of Air Purification by Green Roofs:
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Particle Trapping: The vegetation on green roofs, including leaves and stems, acts as a natural filter. These surfaces physically trap airborne particulate matter (PM), such as dust, pollen, and smoke particles, preventing them from circulating in the atmosphere and potentially being inhaled.
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Absorption of Gaseous Pollutants: Plants absorb various gaseous pollutants like nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3) through their stomata (small pores on the leaves). These pollutants are then utilized by the plants during photosynthesis or are broken down and stored within their tissues.
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Rainwater Wash-off: Rainwater plays a crucial role in washing away the trapped particulate matter. The rainwater carries these particles into the growing medium, where they can be further broken down by microorganisms.
Benefits of Green Roof Air Purification:
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Improved Air Quality: By reducing the concentration of airborne pollutants, green roofs contribute to improved air quality in urban areas. This is particularly beneficial in densely populated areas with high levels of traffic and industrial activity.
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Reduced Respiratory Problems: Cleaner air leads to a reduction in respiratory problems like asthma and allergies.
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Enhanced Environmental Health: Air purification by green roofs contributes to a healthier environment for both humans and wildlife.
Example:
Studies have shown that green roofs can significantly reduce the levels of particulate matter in the air around buildings. This is especially important in cities where air pollution is a major concern.
Conclusion:
Green roofs provide a valuable ecosystem service by helping to clean the air. Through a combination of particle trapping, pollutant absorption, and rainwater wash-off, they contribute to improved air quality and a healthier environment.
