CO2, SO2, NOx, NO2, PM2.5, PM10… these are the abbreviations that name the main air pollutants in Spanish cities. Air quality in many cities „continues to be poor”, says the European Environment Agency (EEA), despite its concentration having fallen significantly over the past two decades on the old continent.
Road transport, coal boilers and industry are some of the main emitters of these gases, which according to the EEA’s latest data in 2020, „96% of the urban population was exposed to high levels of fine particles.” The health-based reference level established by the World Health Organization (WHO).” Changing boilers, moving towards renewables or restricting the cycle for highly polluting vehicles are the most used measures by legislators to reduce the presence of these emissions that harm the health of citizens. On the other hand, cities can „breathe” by increasing green areas. are used as an asset against pollution, but what if not only plants and trees can „breathe” but also street furniture?
This question was raised by Green’s founder Sergey Lopez some time ago. The young Catalan has acquired buses and billboards to 'clean’ the city’s air. „There’s no secret, it’s titanium dioxide,” he explains in a phone conversation. „It all started with reading news about a cosmetic brand’s tarp for air purification, and from there I started investigating,” she recounts. „There were many solutions on the market, and not all of them convinced me, so I did it.”
This time, according to their data, their, still in testing, managed to remove 26 kilograms of NOx (nitrogen oxides) from the atmosphere of cities. „There is nothing in the world that can remove nitrogen oxide from our atmosphere,” he points out. „Reduction by a catalytic chemical reaction is a very efficient technique,” explains López. This is what NOx produces in its reaction with titanium dioxide.
The interaction of sunlight with this chemical compound triggers a reaction that increases the energy of the electrons and allows the decomposition of nitrogen oxides present in the air of large cities and produced mainly by the combustion of vehicles. „For example, the most important thing is to make sure that the varnish on the furniture doesn’t wash off in the rain,” explains López. „They give me a guarantee, I’m speaking for a third party, and it lasts for two years.”
At this time, the first tests carried out by Green’s founder have been in the laboratory for nine months, and he warns that „the performance has decreased slightly, the loss is noticeable, but it is not very dangerous.”
Catalytic Asphalt
So far, this 'eco’ solution has been advertising canvas, paper, vinyl, „and even metals,” says Lopez. „Our products are certified by the Iberian Association of Photocatalysis,” he commented. In recent months, 14 buses in the Barcelona metropolitan area filtered Barcelona’s air with photocatalytic vinyl. According to Greening data, every 2 square meters of this material emitted in cities can offset 10,000 kilometers of pollution traveled by a standard car annually.
However, this is not the only scheme launched in big cities. By mid-2022, Catalonia’s Generalitat has awarded 4.5 million euros to extend a new pavement impregnated with photosynthetic treatment on the Catalan C-31 highway „to help capture nitrogen dioxide pollution.” „The results are not yet in, but the suppliers I work with are immersed in the project and excited,” says Lopez.
Moss around the city
According to data provided by the Iberian Association of Photocatalysis (AIF), the photocatalysis process is the same as photosynthesis. Thanks to solar radiation, most of the urban pollutants are converted into harmless solid waste. „Our customers are interested, but if you tell them they have to pay 10% more, they think about it,” warns this Catalan businessman.
However, his entrepreneurial spirit led him to 'cultivate’ algae across the city. „If we have the tools to improve people’s quality of life, why not use them?” asks Lopez. „Microalgae are photosynthetic organisms with the ability to capture carbon dioxide and release oxygen, making them a promising tool to address environmental challenges,” he commented.
In collaboration with companies and researchers such as Grupo Eulen and G2G Algae, Green’s is developing better ways to allow microalgae to grow in advertising spaces; Additionally, determine the most effective and resistant microalgae species to use in this environment. „We don’t just want to have advertising spaces that clean the air, we want to create networks of billboards that act as little green lungs in our cities,” López reasons.