Itir Sonuparlak reports that Rome's pollution levels exceeded air safety limits 56 times in 2011:
"The city has also been monitoring levels of nitrogen dioxide and PM10, dangerous particles that can bypass natural human filters in the nose and throat and settle into the bloodstream. The data for these particles are especially alarming, the article reports. Traffic is the main source of the alarming PM10 concentrations."
"In response to the alarming levels of pollutants, the city imposed an alternate license plate system last Thursday and Friday. Only cars with even-numbered license plates were allowed in the city on Thursday, and odd numbers on Friday."
While these types of restrictions are controversial, Sonuparlak says that in this case the effect was measurable.
Thanks to Jeffrey Riecke