O gofio bod angen gwerth blwyddyn o ddata i ganfod a yw ansawdd aer wedi gwella ar ôl gosod camerâu cyflymder cyfartalog ar y rhan estyniedig o'r M4 sy'n 50mya heibio i Bort Talbot ac Abertawe, a wnaiff y Gweinidog egluro pam y mae'r canlyniadau hyd yn hyn wedi'i galonogi?
The average speed cameras have only been in place since early September. I cannot yet comment on the effectiveness of the speed cameras to date, as they have only recently been installed.
My recent written statement informed members that we have now published an interim report containing the results of 12 months of roadside monitoring of NO2 levels following the introduction of the speed limits. A further report will be released in March 2020 and will also include speed compliance data for the period following implementation of the average speed cameras.