It's a Miracle!

the church that started it all                        Andrea Giannotti, Gabriele Rossetti

It seems that a special kind of pavement, as in streets and sidewalks, that has been sprayed with titanium dioxide can help cut down on nitrogen oxide pollution by as much as 45 percent: http://www.huffingtonpost.com/2013/07/09/smog-eating-pavement-cut-pollution_n_3563472.html
   Interestingly, this is not a new invention, nor was it invented by the Dutch, as is stated in a recent LA Times article. It was invented by an Italian company in 2006, and that, in itself, is an interesting story. It all started with a Richard Meier-designed church on the outskirts of Rome: http://www.nytimes.com/2006/11/28/world/europe/28smog.html?_r=1&
   More about the church, including lots of photos: http://www.archdaily.com/20105/church-of-2000-richard-meier/