Paris Doing It's Best Beijing Impersonation

A view of the Eiffel Tower seen through thick smog, on March 14, 2014, in Paris

Photo by Patrick Kovarik/AFP/Getty Images

ABC:

Air pollution that has turned the skies over Paris a murky yellow and shrouded much of Belgium for days forced drivers to slow down Friday and gave millions a free ride on public transportation.

The belt of smog stretched for hundreds of miles, from France's Atlantic coast to Belgium and well into Germany. It was the worst air pollution France has seen since 2007, the European Environment Agency said.

Nearly all of France was under some sort of pollution alert Friday, with levels in the Parisian region surpassing some of those in the world's most notoriously polluted cities, including Beijing and Delhi.

To combat the smog, public transit around Paris and in two other cities was free Friday through Sunday. Elsewhere in France and in Belgium's southern Wallonia area, the free ride was only for Friday.

The smog is particularly severe here because France has an unusually high number of diesel vehicles, whose nitrogen oxide fumes mix with ammonia from springtime fertilizers and form particulate ammonium nitrate. Pollutants from the burning of dead leaves and wood contribute as well.

Diesel fumes and ammonia fertilizer making ammonium nitrate?  Never heard of that.