Air pollution: the situation in Marseille is worrying

The authorized limit for nitrogen oxide emissions is 40 µg/m3, still, higher annual average emissions of 75 µg/m3 have been measured. The city decided by precautionary measures to close definitely a creche located near the northern highway. Since this is a lasting problem, may a low emission zone ZCR be implemented besides the existing environmental zone (ZPAd Bouches-du-Rhône) which is activated in case of air pollution episodes?