In densely populated urban areas, such as Los Angeles, smog is a famous problem. The air pollution hangs like a dingy lid over the city, amplified by the urban heat island effect created by impervious surfaces on buildings and hardscaping. With a new discovery, however, those same buildings could one day help scrub the smog out of the air.
Smog is unsightly, but more importantly, it exacerbates lung and heart conditions. According to the World Health Organization, three million deaths a year worldwide are attributable to diseases caused and worsened by outdoor air pollution.
In addition to reducing the sources of pollution which cause smog in the first place, removing existing air pollution is another useful step. A coalition of researchers have discovered that combining graphene with titanium dioxide can degrade 70 percent more nitrogen oxides out of the air versus titanium dioxide on its own.
Titanium dioxide, also known as titania, is a widely used naturally occurring ingredient which is found in everything from paints to sunscreen. It is also a photocatalyst at the nano scale, and under sunlight it can degrade nitrogen oxides and volatile organic compounds into harmless compounds.
Researchers were able to create a graphene-titania nanocomposite material that can be coated onto hard surfaces and passively breaks down air pollutants. The degraded components of the air pollution then could wash away in the rain or wind, and the process does not wear out the photocatalyst.
In addition to degrading nitrogen oxide, researchers found the new compound to effectively degrade rhodamine B, which is similar to the molecular structure of air pollution from vehicles.
Before your facility can become a smog chomping champion, researchers say there will need to be a cheaper way to mass-produce graphene, as well as further research into how to make the coating last as long as possible in the real built environment.
The research was published in the journal Nanoscale.
Naomi Millán is senior editor of Building Operating Management.
