Green roofs and how they can reduce microplastic pollution

This is a significant finding, because microplastics are everywhere - in the air we breathe, the water we drink and the food we eat. While awareness has grown around plastic waste in seas and rivers, atmospheric microplastics are only now being recognised as a major concern. As these particles fall with rain or settle onto impermeable surfaces, they are washed into drains and watercourses, ultimately contributing to wider environmental and human health risks.

However, green roofs according to academics in China, may be one of the simplest and most effective tools for intercepting this hidden pollutant before it spreads further. Until recently, the link between rooftops and microplastic pollution was rarely discussed. Yet in dense urban areas, rooftops represent 40 to 50% of all impermeable surfaces. They are also prime landing zones for atmospheric microplastics carried by wind and rain. Once deposited, particles are easily flushed into sewers and waterways.

In coastal cities, rainfall is one of the main pathways by which microplastics reach aquatic systems. This means rooftops are not just passive surfaces - they are gateways for pollution to enter the wider environment, which is why green roofs can make such a difference.
Research from Shanghai provides some interesting statistics. Scientists there found that modular green roof systems intercepted over 97.5% of atmospheric microplastics under simulated rainfall. When scaled up across the city’s existing green roof area, this translated into preventing more than 56 tonnes of microplastics per year from reaching rivers and drainage systems. That suggests a change in how we design and refurbish rooftops could deliver measurable environmental gains.

How green roofs capture microplastics
The effectiveness of green roofs is due to their layered design, claim the researchers. Soil and vegetation act as filters, trapping particles in much the same way they retain nutrients, heavy metals and other pollutants. Soil layers provide the primary line of defence, capturing fragments and fibres before they infiltrate further.
Vegetation adds a secondary filter, with plant leaves and stems intercepting airborne plastics directly. Rainfall dynamics also play a role with higher rainfall intensity appearing to increase capture efficiency, compacting the soil and reducing infiltration channels. This means that every green roof installed is not just helping manage stormwater or reduce urban heat - it is actively cleaning the air and water of microscopic plastics.
Microplastic pollution is not just an ecological issue - it’s a public health one. Studies have shown that humans inhale and ingest thousands of microplastic particles each year. Their long-term effects are still being studied, but links have already been made to respiratory and inflammatory conditions.

Cities, with their dense populations and high levels of atmospheric pollution, face a particular challenge. Traditional stormwater management tools like retention ponds and wetlands can help intercept plastics downstream, but by then, much of the damage is already done. Intervening earlier at the rooftop level, offers a smarter, preventative approach.
That’s where advanced green and blue roof systems can excel. However, not all green roofs are the same. Their performance depends on factors like substrate depth, plant species and maintenance regimes. Some can even contribute to microplastic release if synthetic materials within the roof degrade over time.

Next-generation systems are designed to address these challenges. For example, the Attenu8® green/blue roof system from Proteus Waterproofing has been developed to deliver reliable stormwater attenuation, while also supporting biodiverse planting that enhances filtration capacity. By integrating proven substrates with vegetation suited to local climates, systems like this maximise both stormwater control and pollutant capture.
The core difference of the Attenu8® System, particularly when combined with a green roof, lies in its unique, patented structural drainage and overflow layer. Unlike many competitor systems, this design allows the underlying roof drainage to be independently engineered to meet the stringent requirements of BS EN12056:3 2000 – delivering an additional bonus for building owners.
However, while Proteus Waterproofing’s primary focus is on managing urban flooding and delivering robust waterproofing solutions, the role of Attenu8® in filtering atmospheric pollutants adds an extra environmental benefit. It demonstrates how commercial roofing technologies are evolving to meet multiple sustainability goals at once, combining good water management, biodiversity, energy efficiency and now, microplastic reduction.

Another step forward for green/blue roofs
Globally and in the UK green roofs are becoming more common. London, for example, has one of the largest concentrations of green roofs in Europe.  The recognition of their role in tackling microplastics could accelerate this momentum. As urban planners and developers seek solutions to meet sustainability challenges, green/blue roofs stand out as a multi-benefit investment, helping to reduce flood risk, cut energy demand, support biodiversity, and filter pollutants. Systems like Proteus Waterproofing’s Attenu8® align with this trend, providing practical, scalable infrastructure that contributes to both resilience and environmental health.
Microplastics are one of the defining environmental challenges of our time and difficult to control once they enter water or air systems. Yet this evidence from China now suggests that rooftops, when designed intelligently, could act as frontline defences against their spread.

The task for industry and policymakers is to integrate these findings into building regulations, sustainability frameworks and refurbishment strategies. The technology is already here. Attenu8® and other advanced green/blue roof systems demonstrate how modern construction can rise to the challenge, by protecting buildings and cities from flooding while cleaning the very air and water that sustain them.