"Cafodd terfynau cyflymder dros dro o 50 milltir yr awr eu cyflwyno mewn pum rhan o'r Rhwydwaith Traffyrdd a Chefnffyrdd er mwyn ceisio gwella ansawdd yr aer ar unwaith. Mesur dros dro oedd hyn wrth i ragor o waith gael ei wneud yn y maes.
“To deliver immediate improvements to air quality, temporary 50 mph speed limits were introduced at the five sections of the Motorway and Trunk Road Network until the outcome of the further work was known.