Air Pollution (5)

MQT on 2016-06-22
Session date: 
June 22, 2016
Question By: 
Leonie Cooper
Labour Group
Asked Of: 
The Mayor


What steps will you take to tackle the illegal removal of diesel particulate filters in the capital?


Answer for Air Pollution (5)

Answer for Air Pollution (5)

Answered By: 
The Mayor

The current London Low Emission Zone (LEZ) requires older heavy diesel vehicles to have a diesel particulate filter, which is subject to an annual Driver and Vehicles Standards Agency (DVSA) inspection.

Enforcement on this issue is part of the role of the DVSA, either through the annual MOT test or roadside spot-checks by examiners. Older heavy vehicles driving in London that have had a failed inspection or no inspection at all are subject to paying the LEZ daily charge.

The TfL-funded Commercial Vehicle Unit carries out visual inspection of exhaust emissions and reports offending vehicles. However, the removal of a diesel particulate filter (DPF) is very difficult to detect on the road side without a pit and various specialist testing equipment. TfL also conducts roadworthiness testing for taxi and private hire vehicles through the licensing process (which supplants the MOT test).

It is likely DPF removal would only be done on older vehicles where the high price of a replacement is a barrier. However, we do not know whether DPF removal is an issue in the UK as data is limited, particularly for smaller vehicles. Thankfully there are no benefits to the driver in fuel savings or performance, only in repair costs for a faulty system, so occurrences are likely to be limited.