Designing For Clean Air: Architecture's Role In Pollution Control

Air pollution is a pressing issue that poses a serious threat to the world. With cities consuming more than 75% of the world's energy and emitting 80% of global greenhouse gas emissions, architects and designers have a unique opportunity to re-imagine buildings as active solutions to combat poor air quality.

Buildings and their construction contribute significantly to global air pollution, and architects play a crucial role in addressing this issue. By making careful choices in materials, ventilation systems, and design approaches, architects can reduce the negative impact of buildings on air quality and even improve it.

This involves selecting materials with low or zero volatile organic compounds (VOCs), integrating greenery, implementing efficient city planning, and retrofitting existing structures to reduce the need for new construction.

Additionally, architects can advocate for political change and collaborate with engineers, contractors, civic leaders, and communities to create sustainable solutions that improve indoor and outdoor air quality.

The challenge of reducing air pollution presents architects with an opportunity to create innovative designs that positively impact the health and well-being of city dwellers.

The role of architects in reducing air pollution

Buildings and their construction are major contributors to air pollution, so architects have a crucial role to play in reducing it.

Sustainable materials

Architects can specify materials from non-polluting manufacturers, such as natural paints with low or zero VOC content, and avoid artificial and synthetic flooring materials like laminates and vinyl. They can also opt for local materials, which are more sustainable and help the building blend with the culture of the city.

Vegetated surfaces

Vegetated surfaces, such as living walls, can be employed to clean and oxygenate the air. An example of this is the Museé du Quai Branly in Paris, which features a living green wall of lush grasses and shrubs that absorb toxins in the air without the use of chemicals.

Efficient city planning

Green spaces can be incorporated into cityscapes to remove carbon emissions from vehicles. When integrated with footpaths and cycling tracks, these spaces can encourage citizens to walk or cycle, reducing private vehicle usage and, in turn, pollution levels.

Avoid demolition and retrofitting

Retrofitting existing buildings is more sustainable than demolishing and rebuilding, as the latter leaves a huge carbon footprint. Old buildings can be restored and retrofitted with pollution-reducing technologies such as the Prosolve370e, a decorative architectural tile that reduces air pollution and can be installed on any existing building.

Efficient transport systems

Architects can design efficient public transport systems that encourage citizens to make use of them, leading to a reduction in private vehicle usage and, consequently, pollution levels.

Education

Architects can educate policymakers and the public about the need to reach zero emissions and the importance of sustainable practices in building design and construction.

Sustainable architecture

Efficient City Planning:

Incorporating green spaces into cityscapes is essential. Architects can design spaces with an abundance of greenery, such as parks and cycling tracks, encouraging citizens to embrace more sustainable modes of transportation and reducing vehicle emissions. Efficient city planning also involves the implementation of well-designed public transportation systems, which can significantly reduce private vehicle usage and, consequently, lower pollution levels.

Integration of Greens:

Plants are natural air purifiers. By integrating green pockets and vertical gardens into building interiors, architects can enhance indoor air quality and create aesthetically pleasing environments. Specific plant species, such as aloe vera and peace lilies, are known for their ability to remove harmful chemicals and toxins from the air.

Selection of Building Materials:

The choice of materials is crucial in sustainable architecture. Architects should prioritize using materials with minimal negative environmental impact, such as natural options like tiles, slates, and local stones. It is also essential to minimize the use of artificial and synthetic flooring materials, such as laminates and vinyl, which can contribute to indoor air pollution. Additionally, using local and natural materials helps maintain the cultural identity of the city while serving its functionality.

Reducing Construction Pollution:

The construction process itself contributes significantly to air pollution. Architects and construction companies should focus on minimizing dust production, reducing the use of volatile organic compounds (VOCs) in paints and finishes, preventing material wastage, and limiting the unnecessary usage of heating and air conditioning systems during construction.

Retrofitting and Reusing Existing Buildings:

Retrofitting and restoring old buildings are more sustainable than demolishing and rebuilding. By adapting existing structures, architects can reduce the carbon footprint associated with new construction. The practice of retrofitting aligns with the principle that 'the greenest building is one that is already built.'

Energy-Efficient Design:

Architects can incorporate energy-efficient systems and renewable energy sources in their designs to minimize operational carbon emissions. This includes the use of electric heating and cooling systems powered by carbon-free energy, such as solar or wind power.

Policy Advocacy:

Architects can play a pivotal role in advocating for policies that support sustainable architecture and urban planning. By educating policymakers about the importance of reaching zero emissions, cities can implement regulations, incentives, and land-use policies that promote sustainable practices and reduce embodied carbon in construction projects.

The use of plants and green spaces in architecture

Plants and green spaces have been shown to have a positive impact on reducing air pollution, particularly particulate matter (PM). However, the effectiveness of plants in improving air quality is still a subject of debate. While they may not be a standalone solution for city-scale air pollution, when combined with other measures, they can be a valuable part of a wider strategy.

Deposition

Living plants can facilitate the deposition of a much higher quantity of pollutants than similarly-shaped artificial structures. This is the most studied mechanism of pollution reduction by plants, with experiments measuring the mass and settling velocity of PM on plant leaves.

Dispersion

Plants can act as a shield, lowering local pollutant concentrations when strategically placed. For example, bushes placed between a road and a pedestrian path can reduce exposure to pollution from exhaust fumes and road dust.

Modification

Plants transform several gaseous and particulate pollutants, either on their surface or within their structures. They can also impact the pre-conditions for air pollution formation, such as air temperature or humidity, which can have both positive and negative effects.

Drawbacks

Plants also have some drawbacks in the context of air pollution. They require maintenance and watering, and some plants produce high levels of biogenic volatile organic compounds (BVOCs). These can mix with NOx from traffic to form ozone, a corrosive secondary pollutant.

Green Infrastructure

The development of design guidelines for green infrastructure is vital to promote and optimize its benefits. Natural science and epidemiology approach the topic of green infrastructure and human health very differently, and more research is needed to establish the underlying policies and guidelines governing its deployment.

Maximizing Benefits

To maximize the benefits of green spaces, it is recommended to avoid plants that produce high levels of pollen or BVOCs, choose low-maintenance plants, and select plants with smaller, complex leaves, which have a larger surface area for pollution deposition.

While there is no one-size-fits-all solution, local authorities and urban planners can make substantial air quality improvements by taking a holistic approach and considering a range of factors when incorporating green spaces into their strategies.

Energy-efficient buildings

One way to improve energy efficiency is to focus on the building envelope, ensuring that it is well-sealed to prevent ambient air pollution and excessive moisture from entering through cracks. This can also help to improve indoor temperature control and reduce exposure to air pollution, leading to improved health outcomes for residents. Additionally, energy-efficient buildings often have enhanced ventilation systems, which can reduce airborne contaminants such as particulate matter, mould, and pest droppings.

Another strategy is to utilise renewable energy sources such as solar, wind, and water power to generate electricity for buildings, reducing the reliance on fossil fuels. This can be coupled with the use of electric appliances such as heat pumps and induction stoves, which are more efficient and less polluting than traditional fuel-burning appliances.

Architects can also incorporate natural processes into their designs to improve air quality. For example, living green walls, such as the one designed by landscape architect Patrick Blanc for the Museé du Quai Branly in Paris, absorb toxins in the air without the use of chemicals. Similarly, the BIQ or Bio-intelligent quotient house in Hamburg, Germany, features a bioreactor façade with an algal culture that converts carbon dioxide into oxygen through photosynthesis, while also filtering light and reducing heat gain.

By implementing these strategies and more, architects can play a crucial role in reducing air pollution and creating a healthier, more sustainable future for urban residents.

The impact of construction on air pollution

The construction industry has a significant impact on air pollution, contributing to around 25-40% of the world's carbon emissions. This is largely due to the burning of fossil fuels and the use of diesel-powered machinery and vehicles, which release a range of pollutants into the air, including carbon monoxide, carbon dioxide, nitrogen oxides, and hydrocarbons. In addition, construction activities such as land clearing, demolition, and the use of hazardous chemicals can also contribute to air pollution.

Sources of Air Pollution in Construction

Machinery and Vehicles

A major source of construction-related air pollution is the use of plant machinery and vehicles on-site, which are often powered by diesel engines. Due to the scale of many construction projects, this equipment is often running for extended periods, releasing pollutants into the air for a long time. The exhaust from diesel engines contains gases such as carbon monoxide, carbon dioxide, nitrogen oxides, and hydrocarbons, which can have harmful effects on both human and environmental health.

Dust and Particulate Matter

Construction and demolition activities, such as excavation, land clearing, and road construction, generate significant amounts of dust. This dust contains particulate matter and volatile organic compounds (VOCs) that can be spread around the construction site and surrounding areas by wind. Particulate matter, especially that which is 2.5 micrometres in diameter or smaller (PM2.5), can penetrate deep into the lungs of those who inhale it, leading to respiratory issues and other health complications.

Greenhouse Gas Emissions

The burning of fossil fuels and diesel during construction activities releases greenhouse gases, contributing to climate change. In addition, the production of concrete, a common building material, generates a significant amount of carbon dioxide emissions.

Hazardous Chemicals

Construction sites often involve the use of hazardous chemicals such as paints, glues, oils, thinners, plastics, and other toxic substances. These chemicals can release noxious vapours and, if not managed properly, can end up in water bodies, causing water pollution.

Reducing the Impact of Construction on Air Pollution

While construction activities can have significant negative impacts on air quality, there are ways to reduce these effects. Here are some strategies to minimise the air pollution caused by construction:

• Sustainable construction projects: Designing construction projects with sustainability in mind can help reduce their environmental impact. This includes using renewable or sustainable materials, such as timber from sustainably managed forests.
• Energy-efficient buildings: Increasing the energy efficiency of buildings can not only reduce their carbon emissions but also their overall impact on the environment.
• Emission reduction targets: Setting targets for reducing emissions can help construction companies prioritise the reduction of air pollution and take proactive steps towards cleaner practices.
• Minimising pollutant discharge: Construction sites can minimise the discharge of pollutants by adopting dust suppression techniques, such as using water sprays or sprinklers, and implementing proper waste management practices.
• Low-emission machinery: Using low- or zero-emission construction machinery and equipment, such as battery-powered options, can significantly reduce air pollution and greenhouse gas emissions.
• Air quality monitoring: Establishing a high-resolution air quality monitoring network can help quantitatively measure the impacts of construction activities and the effectiveness of any measures taken to reduce pollution.

The construction industry has a responsibility to limit its impact on air pollution, and by implementing sustainable practices and new technologies, it can play a crucial role in improving air quality and mitigating climate change.

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