Titanium Dioxide in Concrete: What Could Possibly Go Wrong?

"Could pollution-eating concrete clean up our urban jungles?"
CNN (August 6, 2010)

"Concrete isn't usually considered an environmentalists' friend, but a remarkable new technology could soon be turning the gray stuff green.

"Scientists at Eindhoven University of Technology in the Netherlands have developed a paving material that actually eats pollution, claiming it could soon become a crucial tool for improving air quality in urban areas.

"The problem in many cities is that vehicle exhausts emit nitrogen oxides, which cause acid rain and smog that damages not only human health and quality of life but also the fabric of buildings.

"But the new concrete is coated with titanium dioxide, which is a photocatalytic material, meaning it removes the nitrogen oxides and uses sunlight to convert them into harmless nitrate that is washed away by rain...."

I remember when asbestos was the wonder-mineral that saved lives by containing fires. The stuff was everywhere. It worked just fine as a fire barrier and an insulator. Then we found out that asbestos fibers don't play well with our lungs, and now there's a whole industry built around safely removing asbestos.

The CDC's description of titanium dioxide is - interesting:

"...Exposure Routes
"inhalation
"Symptoms
"Lung fibrosis; [potential occupational carcinogen]
"Target Organs
"respiratory system
"Cancer Site
"[in animals: lung tumors]..."
("Titanium dioxide," NIOSH HomeNIOSH Pocket Guide to Chemical Hazards (NIOSH Publication Number 2005-149) (September 2005)

Sounds like the folks at Eindhoven University of Technology have another wonder-mineral on their hands. Yes, at long last the dangers and discomfort of urban pollution are at an end: thanks to the wonders of modern technology!

I can see the ads now: Use new, improved concrete: now with titanium dioxide! It eats nitrogen oxides! Use EUT's new, improved oxide-eating concrete now! Be ecologically aware!

Well, maybe not quite like that. But I'm pretty sure that there's going to be an effort to make cities which don't use EUT's pollutant-eating concrete seem backward, while praising forward-looking outfits that do.

Sounds almost too good to be true: concrete, something that's almost everywhere in contemporary cities, may now absorb pollution.

Carcinogen in Concrete: What Could Possibly Go Wrong?

Ever notice how, in almost every construction project, there's a lot of dust? Quite a lot of that is from concrete that's pulverized as old sidewalks, roadways, and walls are broken apart to make room for new structures.

Somehow, I don't think that all the titanium dioxide in EUT's wonder-concrete will have reacted with nitrogen oxides, by the time it's knocked apart for street maintenance or new construction.

Some time after that dust settles, my guess is that there's going to be a spike in lung fibrosis and cancer among folks living in ecologically-aware cities.