you got all these cars with these filters on are they really worth buying any of them when you do 300 miles around town then you have to take a trip for 20 minutes to clear the dam things out what a waste of fuel .

How many people drive 300 miles solid urban driving without an interim run on a dual carriageway? Those that do would have been better advised to opt for petrol.

It's only fair that as technology improves the benefits are shared between the operators of the vehicle and those standing outside the vehicle. If you don't want a DPF then buy a pre Euro V vehicle.

But think about the scalability of your DPF delete 'solution': If everyone removes their particulate traps and city air quality does not improve, the result will be ever more draconian emissions legislation in a bid to siolve a problem that does not need to exist. Think of 1970's American cars...

or do pollutants only count in the EU???

Pollution is a localised problem. CO2 can be considered a global problem, but NO/PM is only of interest in areas of high vehicle density such as city centres.

lmao my question as been answered in this video

https://www.youtube.com/watch?v=zwjamZ98Ebk

in order to a full regeneration you have to hard drive it for 20mins in 4th gear at over 2500 revs

No. This is what people who don't let ignorance get in the way of trying to find a solution to a problem and blaming everyone else when they don't succeed.

Using the highest gear possible gives the best fuel economy and the highest exhaust gas temperatures which aid soot burn-up.

Running around in low gears with the revs screaming away achieves neither.

Don't take my word for it. Join a truckers' forum and try telling them that running round in a low gear gives high EGTs or clears DPFs. They often have exhaust pyrometers so they know what's going on.

Some of these recurring DPF problems will be due to faults on those particular vehicles (faulty pressure sensors etc) which have been misdiagnosed as blocked DPF.

The plumes of black smoke that you used to see (Ford 2.3?) have largely been obviated by diesel injection and combustion technology advances, rather than solely by the DPF.

Take a relatively modern car without a DPF (Hyundai/Kia for instance) and compare its output to a Perkins 4.236 hoofed into a landy and you will see what I mean.

The black smoke is just the visible element of the poor combustion. It too contained all of the partially oxidised fuel, aromatics and nano particles, left to roam free when the rest settled as dust.