Question to the Department for Transport:

To ask the Secretary of State for Transport, for what reason transport refrigeration units are exempt from the Clean Air Zone Framework in England.

Individual refrigeration units can cause significant levels of pollution; however the standards set out for charging Clean Air Zones (CAZs) set out in the CAZ framework are focussed on vehicle tailpipe emissions, which are the greatest source of roadside pollution by a significant margin.

There are also technical limitations to using CAZs to control such vehicles. CAZs rely on Automated Number Plate Recognition to identify the Euro class of a vehicle but cannot identify whether or not they are a refrigerated vehicle; it would not, at present, be possible to use a CAZ in this way.