New DPF Filter Effectiveness Queried by Scientists

Are we getting the whole truth about DPF Filters?

The effectiveness of the DPF filters has long been disputed, but now evidence has come to light suggesting the troublesome filters may not be as great as the car manufacturers say. The filters, which work through trapping larger particles of engine soot, can quickly become blocked and are often resented by drivers for limiting car ability, causing breakdowns and adding to the already heavy cost of car ownership- not least the cost of their eventual removal and replacement.

A study from the University of Notre-Dame in the USA claims that post 2007 diesel fumes (NDTE-2007) while lower, carry a soot whose particles are finer, negating the effects of a filter by simply ‘slipping through the net’ more often. Though the newer engines produce less, what they do produce is not only adept at escaping the filter but also- possibly more dishearteningly- at infiltrating the body through the nose, and ultimately, into the brain or lungs “where it can cause chronic inflammation and organ degeneration”. These ‘ultrafine’ particles can travel long distances on the wind- and pose a more serious risk to health, the article claims.

Further, more questions are being asked about DPF filters and their effectiveness, especially as newer engine technology continues to drive down emissions and the industry may even be less likely to pursue lower emissions if relying on DPF filters. For example, while DPF filters effectively isolate pollution, especially away from roads where you can regenerate or ‘burn’, such as in busy cities, this pollution must nonetheless be released somewhere- either burned off on motorways or disposed of by garages. The environment sees this dusty, dangerous ‘DPM’ again even if it doesn’t happen while driving normally. Indeed, it has been suggested that the required long drives at speed down motorways simply to clean the filter may offset any environmental benefit.
Whether DPF filters will be around forever, or whether industry experts will design new, more effective ways of emissions control remains to be seen. However it’s clear that while the jury is still out on the question of DPM a clean, well-maintained DPF is the best way to combat the harmful effects of diesel fumes. The need for informed, responsible car ownership and careful driving is as paramount as ever and there’s no reason to neglect your DPF filter- on older cars especially.

You can view the article on DPM problems here: