I have received the information below which may be of interest to you.
“As you may be aware, DEFRA are proposing to mandate 5 cities in the U including Leeds to impose a Clean Air Zone to accelerate the improvement in air quality and reduce pollution levels to below the EU target levels by 2020.
Whilst mandating the needs for a CAZ, they will not mandate either the required boundary or the vehicle classes which will be affected.
However, they have suggested that their own modelling indicates that a minimum Euro 4 petrol and minimum euro 6 diesel for all vehicles other than the private car within the outer ring road of Leeds would deliver the required improvements in air quality – providing other supporting measures are put in place.
As a minimum we must look at the scenarios that they are proposing.
The purpose of the ANPR data collection is so we can to understand in detail the make-up of the traffic fleet entering the city in general and using particular roads and understand the number/ proportion of different vehicle classes which contribute to the pollution levels and how many individual vehicles would be affected by the different scenario which we assess.”