Modern cities are vibrant, complex environments, but all face the same problem: air quality. Atmospheric pollutants are often invisible, but their effects on our health can be serious. And when combined with the urban heat island effect, air pollution also causes respiratory and cardiovascular problems. It’s a situation that gives plenty cause for concern, but it can be changed. How? Thanks to ambitious new European regulations and innovative urban management strategies which, together, can make the difference in terms of air quality and living conditions in cities. Transforming our cities into havens of clean air and comfort may appear utopian, but it’s something that urgently has to be done if we’re to secure the future of our cities for our own and future generations.
Care City | Making the air in our cities more breathable
Saturated air: understanding the origins of urban pollution so we can tackle it effectively
Much human activity is concentrated in cities, and one direct consequence of all this activity is pollution: emissions from traffic, industry and domestic heating mix to form a cocktail of pollutants: including fine particulate matter, nitrogen dioxide and ozone. These three pollutants are known to cause respiratory and cardiovascular problems and reduced life expectancy. With their high population density and tangled, often inefficient infrastructure, cities seem ill-equipped by their very nature to tackle the air pollution issue. And the problem is further compounded by the urban heat island phenomenon. Intensively-concreted zones trap heat just as air pollution does, causing respiratory difficulties and other health problems. Ultrafine particles from vehicle exhausts and brakes penetrate the lungs and bloodstream. They are known to cause - and aggravate - illnesses including asthma, heart disease and lung cancer. They’re invisible, and they’re dangerous - especially for young children and the elderly, whose immune systems are weaker. The good news is that people are finally becoming aware of the dangers of air pollution. The challenge for the future is to translate awareness into concrete action that effectively reduces air pollution in the heart of our cities. Strategies to achieve this goal are now being deployed.
More stringent regulations for cleaner air
European regulations imposing limits on the different pollutants in the urban environment were made tighter in February 2024. The new directive aims to significantly improve air quality by halving atmospheric pollution thresholds by 2030. It’s an ambitious goal, perhaps even an unrealistic one. Many cities already have trouble respecting the previous thresholds, so we can reasonably doubt their ability to meet even stricter ones. It’s a huge challenge, and we need to find effective and lasting solutions to the problem of air pollution in cities – especially in the case of new urban development and infrastructure projects. Such solutions must be incorporated in each project at the planning stage if the health impact of air pollution is to be reduced to a minimum. Some cities are beginning to take action...
Responses to air pollution in cities
The proposed solutions to air pollution vary from one city to another. Among the most frequent, as of 2024, we can cite:
- Low emission zones (LEZ), which are designed to reduce air pollution caused by vehicle emissions;
- Encouraging the use of collective transport, electric vehicles of all types, and bicycles to reduce the impact of vehicle-related pollution;
- Building parks and green roofs to increase the presence of nature in cities;
- Sustainable energy management, promoting the use of renewable energy and cleaner heating to reduce emissions from buildings – heating is a major source of pollution in cities;
- Raising awareness: educating and informing the public on the importance of reducing air pollution and its impact on the health of city-dwellers.
Innovation: a breath of fresh air in our cities
Vegetation plays a key role in the fight against the urban heat island effect. Not only does it have a cooling effect on the air, it also filters out certain atmospheric pollutants. This is the reason vegetation is included on a near-systematic basis in more and more urban construction and refurbishment projects. But other innovative solutions exist too, and deserve our attention. Some are still at an embryonic stage, it’s true. But in the future, they may come to play a key role in the efforts of cities to keep air pollution as low as possible. It’s a major challenge in terms of public health, but it’s also an opportunity to renew our cities and make them more attractive!
Air quality in our cities: solutions do exist
In 2023, Egis conducted a benchmark survey evaluating innovative solutions for reducing urban pollution and treating pollutants for Eurométropole de Strasbourg. This benchmark drew on French and international data and ranked the solutions by maturity, rapidity, efficacy and cost. Among the solutions examined were self-cleaning, pollution-removing façades. These façades are coated with titanium dioxide, a photocatalyst which acts to remove nitrogen oxide, ozone and VOC from the atmosphere. This coating also has bactericidal, self-cleaning properties. Claims regarding the amount of ozone and VOC filtered out of the atmosphere by titanium dioxide were found to be exaggerated, however. And titanium dioxide is itself classed as a carcinogen, which raises other health issues.
Apps like Naonair, IQ Air and Plume Labs allow us to monitor air quality in real time, which is useful for e.g. planning travel routes. However, these apps don’t provide data on exact levels of exposure to air pollution, which can vary significantly over short intervals of space.
In vehicle braking systems, technologies like TAMIC® by Tallano Technologies, the inductive braking solution developed by Telma and iDisc by Buderus Guss (a subsidiary of Bosch) have shown an impressive ability to filter out fine particles emitted by vehicle brakes. The Tallano Technologies system has been trialled on line C of the Île-de-France regional rail transit network, and may be extended to other lines if the benefits for air quality are confirmed.
Finally, there are urban particle filters such as TrapAparT (a passive, washable solution) and Filter Cube by MANN+HUMMEL (an active system capable of filtering out large quantities of particles and other pollutants). However, the benefits of Filter Cube are offset by its energy consumption and consumables costs. Still, these technologies do hold promise for improved urban air quality in the future.
