The particulate filter (DPF - Diesel Particulate Filters) serves to limit emissions of fine dust (PM10 mainly) of diesel engines. It is currently the best technology available for this purpose and that makes it important. The advantages are indisputable, but there are some flaws that should be considered.
In the city, vehicular traffic is responsible for 70% of PM10 emissions, which frequently exceed the legal limits and make the air unhealthy. The fault lies mainly with diesel vehicles because they emit fine dust more than gasoline. Considering that many more diesel cars have been sold in recent years, the air in the city should be unbreathable.
If this has not happened, indeed there is some improvement in the air quality, it is mainly thanks to the technology of particulate filters mounted on cars. These are obviously not free, sometimes presented as expensive options, but they are definitely useful and should be part of the standard equipment of diesel cars.
Advantages of the particulate filter
The advantages are all for the environment and for the community. If we were to make a selfish speech, the driver is left with only the extra expense and, if anything, the possibility of entering some ZTL. But the game is worth the candle. The particulate filter it reduces by 90-95% the emissions of fine dust particles, of all diameters and not only PM10. It also reduces emissions of carbon monoxide (CO) and unburnt hydrocarbons (HC). A reduction of Polycyclic Aromatic Hydrocarbons (PAHs) and other compounds is also obtained. Therefore the particulate filter mounted on diesel engines is certainly positive for the quality of the air we breathe.
Disadvantages of the particulate filter
The first is that with the particulate filter the car's consumption increases (by about 3%) due to the exhaust back pressure caused by the progressive clogging of the filter. Another disadvantage of the particulate filter is that it requires periodic cleaning, a process called regeneration, to prevent it from becoming clogged and reducing the car's performance.
After regeneration the CO emissions increase slightly, but so little that it is not a problem. At one point the particulate filter it must also be replaced because regenerations are no longer enough. On average, the replacement takes place after 80-100 thousand kilometers, but on the latest models it can even reach 180 thousand km.