Smog-eating sidewalks

Rico says his friend Kelley forwards this, from Yahoo! News:

The eco-makeover of urban surfaces continues. First came white roofs. Then so-called cool pavement. And now smog-eating concrete.
Yup, sidewalks with a taste for filthy air.
Eindhoven University of Technology scientists have installed air-purifying cement onto a city block in Hengelo in the Netherlands and published the results, which found that it reduced nitrogen oxide air pollution up to 45 percent in ideal weather conditions. This is an average reduction of nineteen percent each day.
The concrete, dubbed “photocatalytic”, is made with run-of-the-mill cement sprayed with a chemical— titanium oxide— that neutralizes air pollutants, the researchers’ abstract states.
"The concrete could be a very feasible solution for inner city areas, where they have a problem with air pollution," said researcher Jos Brouwers in 2010, when the pavement was in its early stages.
So, what's the world waiting for? Why aren't urban jungles with smog problem— we're especially looking at you, Beijing— not jackhammering every piece of old school pavement and pouring the new stuff?
Well, like most public work projects, it all comes down to cost. Titanium dioxide pavement is simply more expensive than your grandfather's cement.
But, with further product tinkering and price–reduction, air-scrubbing pavement could be the stomping ground of the future.