The most common number associated with sustainability is zero. In the coatings industry, many of us have worked on achieving targets for Zero VOC, Zero Waste, Net Zero Emissions. The use of the number zero to represent our sustainability targets is a reflection of our industry’s sustainability paradigm that traces its roots to the principles of green chemistry laid out back in 1998. We think of sustainability in terms of “doing no harm” to health and the environment in the products we make and how we make them, with zero harm being the ultimate target.
This approach to sustainability is not unique to the coatings industry—indeed companies in just about every industry have adopted Net Zero targets. While it is just as important for coatings companies to achieve such Net Zero goals as it is for companies in other sectors for the world to achieve its climate goals, there are unique characteristics of the coatings industry that can allow us to concurrently broaden our sustainability thinking in terms of going beyond zero —to not just be net neutral but actually be a net positive. Paint technology has developed products that get beyond doing no harm to actually making a positive impact on the environment. And the more we can involve our customers in using such products, the more we can multiply that positive impact.
Pacific Paint (Boysen) Philippines, Inc. the largest paint manufacturer in the Philippines, has adopted this expanded notion of sustainability. In addition to implementing programs to make green paints in a green way, the company is using coating products to help address two critical environmental challenges in the Philippines—air pollution and climate change.
Painting Solar Powered Air Purifiers
Our external environments are full of paintable surfaces—and paint technology can now transform all those surfaces into solar powered air purifiers.
According to the World Health Organization (WHO), air pollution is the single greatest environmental risk to human health, with an estimated 6.7 million premature deaths annually across the world due to air pollution. A WHO study from May 2018 found that the Philippines ranked third in deaths due to outdoor air pollution (45.3 deaths per 100,000 individuals).
Any visitor to Manila can easily see why. Rush hour traffic forces vehicles to sit idly in traffic, where they emit pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs), which react under sunlight to form a thick layer of smog that hovers over the city and silently shortens the life span of the city’s people.
There are few practical ways available to clean these pollutants once they exit a vehicle’s exhaust pipe. A possible solution would be to install air purifiers all over the city, but this is so difficult that no city has tried doing this. However, our external environments are full of paintable surfaces— and paint technology can now transform all those surfaces into solar powered air purifiers. Air purifiers that can be easily installed by painting, don’t require maintenance, can’t be stolen, and keep working as long as they’re exposed to ultraviolet (UV) light.
In various parts of Manila, the paint being used to convert ordinary walls to air purifiers is Boysen KNOxOUT, the world’s first air-cleaning paint with CristalACTiV photocatalytic technology. It has been proven to break down air pollutants such as nitrogen oxides (NOx), sulfur oxides (SOx), and volatile organic compounds (VOCs), and convert them into harmless substances through a process called photocatalysis, a natural reaction occurring in the presence of light, water and oxygen.
On a KNOxOUT paint film, light energy activates the ultrafine TiO₂, which then converts ordinary water vapor into free radicals that break down NOx that come into contact with the surface of the TiO₂ particles. Because of its small size—6,500 of the TiO₂ particles can be laid end to end across the width of a human hair—a gram of the material has a surface area of a tennis court, and this large surface area promotes a high level of contact and activity with air pollutants.
The NOx gas is converted into very diluted nitric acid, which is rapidly neutralized by alkaline calcium carbonate particles in KNOxOUT, producing harmless quantities of calcium nitrate, water, and negligible amounts of carbon dioxide and water. Calcium nitrate is water soluble and easily removed from the film, leaving a fresh surface ready to engage the next pollutant to come into contact with the film. Because the ultrafine TiO₂ is merely a catalyst in generating free radicals, it is not consumed in the reaction, allowing KNOxOUT to continually clean the air as long as exposed to sufficient light.
While most of the industry was focused on developing zero VOC paints, KNOxOUT introduced the concept of a negative VOC paint that could remove more VOCs in the environment than the amount of VOCs in the paint formula. More significantly, by giving anyone with a paint brush the power to transform an ordinary wall into a solar powered air purifier, it was expanding our industry’s sustainability efforts to include our customers. Since just about everyone can use a paint brush, everyone could now become part of the solution to air pollution.
To highlight the empowering nature of this technology, Boysen launched the world’s first large scale air cleaning public art project using KNOxOUT along EDSA, the busiest and most polluted roadway in Metro Manila. EDSA had been the scene of the People Power Revolution in 1986, and 5,000 square meters of wall along this road was transformed into air purifiers.
One stretch of colorful lung shaped trees captures the essence of the project—the painted trees are not simply representation of trees, they are acting as if they were live trees. For just as trees act as lungs of the earth by converting carbon dioxide to oxygen through photosynthesis, these painted tress are acting as lungs of the city by converting noxious air pollutants to harmless substances through photocatalysis. And while limited space prevents people from planting more trees, anyone could paint a tree with KNOxOUT.
This concept was expanded internationally with he City Forests project of Converse that used KNOxOUT to install air cleaning artworks in Warsaw, Bangkok, Lima, Belgrade, Sao Paolo, Johannesburg, Santiago and Sydney. Lima already had about 20 artworks using KNOxOUT in different parts of the city due to the work of an NGO called AIRE, and Warsaw also had several air cleaning murals installed by Eco Evolution.
(Reprinted from Coatings World, April 2023).