Stick to the Rules

Commercial Vehicle Workshop magazine features the rules regarding Diesel Particulate Filters and MOT, and how treatment can be more effective than removal.

Recent changes have been made to MoT rules regarding Diesel Particulate Filters (DPFs). DPFs are commonly fitted as standard to new diesel cars and vans to enable manufacturers to comply with air pollutant emissions standards (Euro limits). They reduce emissions of airborne soot particles from diesel exhaust, which are harmful to human health – especially in city centres where localised pollution builds up. Measures such as DPFs are clearly needed as in many UK cities air pollution regularly exceeds limits deemed ‘safe’ by the EU.

However, in vehicles that are left idling or stuck in slow moving traffic for significant periods, soot levels can build up surprisingly quickly. This can block up the DPF and cause operational difficulties.

A tendency for frequent DPF blockage in vehicles making short runs in and out of town can make it tempting to simply remove the filter entirely to avoid further problems. But these are exactly the vehicles in which the DPF is most needed in order to improve air quality in inner cities. Faced with the possibility of hefty fines from the EU for breaching air quality limits, it is unsurprising that the UK government is beginning to crack down on this shady practice of DPF removal.

Read more: Stick to the Rules