ACAP calls for ultrafine-particle testing at mandatory vehicle inspections

Removing or tampering with particulate filters in diesel vehicles is a worrying trend, according to ACAP, with direct consequences for pollutant emissions and public health.

To tackle the practice, ACAP is calling for ultrafine-particle measurements to become mandatory at periodic vehicle inspection centres, through the introduction of dedicated equipment. This is one of the association’s five key measures that it intends to present to the next Government.

Ultrafine-particle testing at vehicle inspections

At present, inspection centres use only opacimeters, which assess the opacity of exhaust gases. This approach cannot identify excessive concentrations of fine particles or establish whether a particulate filter is missing. As a result, many vehicles may remain on the road while producing emissions far above the legal limits.

ACAP’s proposal is to introduce devices that can accurately count particles per cubic centimetre. Such systems are already in use in other European countries and can identify readings above the legal threshold of 250 000 particles/cm³, set for vehicles type-approved to the Euro 5b standard or later.

According to ACAP, the investment required from inspection centres would be comparable with that needed for opacimeters. Under this measure, vehicles with manipulated, non-functioning or absent emission-control systems would fail their inspection immediately.

Particulate filter tampering and its environmental impact

As ACAP notes, altering particulate filters is not merely a technical infringement; it is also an environmental setback. Vehicles in this condition release particles at levels dozens of times higher than those whose filtration systems remain operational.

Alongside the introduction of particle counters, ACAP supports stronger training for vehicle-inspection technicians and a public awareness campaign highlighting both the risks and the illegality of removing these systems.

Modern enforcement for cleaner vehicles

ACAP’s proposal forms part of a broader approach to controlling pollutant emissions and renewing the vehicle fleet. It is one further element in making the automotive sector an active contributor to decarbonisation and improved air quality.

As the average age of the vehicle fleet rises, alongside imports of used vehicles, the technical rigour of periodic vehicle inspections becomes even more important. ACAP also believes the measure would have significant effects in detecting fraud.