Los Angeles and London ( CNN ) -- Can the roof of your house help you breathe easier by reducing the amount of harmful pollutants from urban air ? `` Yes , '' claims John Renowden , vice president of technology at Boral Roofing , a U.S. company that has introduced a line of roof tiles that they say have pollution-busting properties . Based near Los Angeles , the most ozone-polluted city in the U.S. , according to 2012 rankings by the American Lung Association , the company says its `` Smog-Eating Tiles '' improve air quality by neutralizing smog-forming nitrogen oxides released by most vehicles ( read more about smog in our fact box ) . The tiles are coated with titanium dioxide , a photocalyst that can oxidize harmful air pollutants emitted in the burning of fossil fuels . When exposed to natural light , the titanium dioxide breaks down nitrogen oxides in the air and turns them into harmless calcium nitrate . `` Calcium nitrate ... washes off your roof with normal precipitation and is a regular garden fertilizer , '' said Renowden . He notes that the tiles typically add between $ 600- $ 1000 to the price of tiling an average roof . He adds that over a one-year period , the tiles on a 2,000 sq/ft house can oxidize nitrogen oxides `` equivalent to driving 10,000 miles a year in your car . '' Read more : Ancient 'air-conditioning ' cools building sustainably . Boral Roofing claims to be the first construction company in the U.S. to introduce titanium dioxide coatings to roofing products . The technology originates in Japan and has been adopted in Europe by a number of industries . In the last few years , it has been used in the production of several products , including eco-friendly cement , architectural panels and paints . The de-polluting properties of titanium dioxide , a compound commonly used as a white pigment in paints and plastics , were tested in a European Commission-backed project in 2005 . `` Tests in urban settings determined that some pollutants , such as nitrogen oxides , which are a major pollutant contained in exhaust gases , could be reduced by 20-70 % , '' according to the European Commission 's Environmental Technologies Action Plan . Read more : The eco artists turning trash into treasure . Air pollution is one of today 's biggest urban problems . It poses a serious threat to the health of city dwellers , according to experts . Air pollution -- outdoor and indoor -- is estimated to cause more than two million deaths a year worldwide , according to Maria Neira , director of health and environment at the World Health Organization . `` It is definitely one of the biggest health challenges we are confronted with today , '' she said . Exposure to urban air pollutants can increase the risk of cardiovascular diseases and cancer as well as trigger asthma attacks , she added . A recent study on the UK 's air quality by MIT pollution experts Steve Yim and Steven Barrett found that traffic pollution is killing more people than road accidents per year , causing 13,000 premature deaths on an annual basis . A brief uptick in traffic-related air pollution may also be enough to increase a person 's short-term risk of stroke , another report found in February this year . Four in 10 Americans live in counties with dangerous levels of either ozone or particle pollution , according to the American Lung Association . The organization 's recent State of the Air 2012 report found that California is home to many of the country 's most polluted cities , with Los Angeles continuing to top the list of ozone-polluted cities thanks to its heavy road traffic and trade ports . Renowden says that more sustainable solutions are needed in the fight against urban air pollution . `` We have to move past our oil dependence but it wo n't happen overnight , '' he said . Read more : Hacking the city for a greener future . Janice Nolen , national policy adviser at the American Lung Association , says that rather than dealing with the harmful effects of air pollution , the focus should be on tackling the problem at source . `` What we have found historically in any kind of pollution is that the best way to tackle the problem is to clean up the sources , '' she said , `` rather than trying cleaning it up afterwards when it 's in the air . '' `` If you can keep those raw ingredients that make up ozone from coming out of the tailpipes and the smokestacks , then you do n't have to worry so much about cleaning it up later on , '' adds Nolen . Isha Sesay , CNN contributed to this story .
`` Smog-eating tiles '' can oxidize the smog-forming nitrogen oxides released in the air . The technology is used in a number of industries for the creation of eco-friendly products . Experts warn air pollution poses a serious threat to the health of city dwellers . Los Angeles has the highest levels of ozone pollution in the United States .