Well, it’s not that simple, but scientists are hard at work finding ways to use architecture to neutralize the worst kinds of air pollution. High-tech innovation involving titanium dioxide (TiO2) is giving green builders new tools. As you read this, a hospital coated in TiO2 is eating smog in Mexico City. It may soon happen at a building near you.

The Manuel Gea González Hospital cleans the air around it. (Alejandro Cartagena/Elegant Embellishments)

Mexico City’s Manuel Gea González Hospital is a signature project of Berlin-based Elegant Embellishments, an architectural firm that developed a system of decorative, TiO2-coated tiles designed to take pollution right out of the air. American architect and Elegant Embellishments co-director Allison Dring explains how it works in her TEDx talk. The articulated modules facilitate air flow through surfaces that give the TiO2 maximum opportunity to work. Combining air-scrubbing chemistry with cool design “to make environments better at a molecular level” is Dring’s mission and that of design partner Daniel Schwaag.

Already used to whiten sunscreen and paint, TiO2 was first put to use in architecture when the cement manufacturer Italcementi Group developed a self-cleaning cement a decade ago. The discovery soon after, that TiO2 also cleans the air, expanded its potential for the green-building industry.

How it works

TiOis photocatalytic, which means it is activated when sunlight hits it. Ultraviolet light stimulates an interaction between TiO2 and harmful pollutants — such as nitrogen oxides (NOx) and particulate matter — turning polluting gases and organic matter into more benign compounds.

(1) Sunlight hits a surface treated with titanium dioxide (TiO2), which is energized by ultraviolet light. (2) TiO2 interacts with polluting gases and particulate matter. (3) They become less harmful. (State Dept./Doug Thompson)

Another application, developed and marketed by Alcoa Inc., is a TiO2 coating that bonds to aluminum panels. Alcoa claims that its EcoClean with Reynobond panels not only clean the air around them but clean the building itself by helping pollutants wash away easily when it rains.

More ways to paint the town green

For their part, scientists at the University of California, Riverside, are testing anti-smog roof tiles. And in the Netherlands, scientists are spraying TiO2 on roads and reporting remarkable results: reduction of air pollution by 45 percent.

Roof tiles painted with titanium dioxide may help improve air quality. (© photowind/Shutterstock)
Roof tiles painted with titanium dioxide may help improve air quality. (© photowind/Shutterstock)

These solutions are promising, and improved air quality is good, but there are concerns. Hazardous substances are created in the manufacture of titanium dioxide, and more research is needed on water runoff from TiO2-coated buildings and on the possible health effects of TiO2 nanoparticles.

But as experiments continue with TiO2 and other pollutant-absorbing materials, such as biochar, produced from burned organic matter (biomass), green builders have a strong foundation for future success.