Some cars emit thick black smoke even though they have passed the measuring stations. A simple test is enough to reveal the problem – reaching into the exhaust. If soot appears on your fingers, the car does not have a functioning particulate filter.
The so-called DPF filter is mainly used in diesel cars, and it has been mandatory since 2010. In order for it to work properly, it is necessary to keep the engine at higher speeds from time to time, otherwise the filter will clog. However, some drivers, for example, cut out the clogged ceramic insert or drill a hole in the filter due to expensive parts. “Then we have a vehicle that not only does not have a particulate filter, but also has a defect that causes high emissions,” explains Michal Vojtíšek, an expert in combustion engines and emissions from the Mechanical Engineering Department in Prague.
Various measurements point to the problem. About a hundred cars drove through the measured section in an hour and a half, and the devices showed higher concentrations of dust particles in about a tenth of them. According to scientists, the situation is improving, thanks to stricter automotive legislation. “Cars have engine management, catalytic converters, particle filters – and thanks to that (we have) slightly better air than we used to have. Even though there are more and more cars,” explains Vojtíšek.
Scientists recently conducted similar measurements on buses and boats on the Vltava. It was around the river that the test did not go well. “The particle concentrations we measured were frighteningly high, much worse than at the Florenc bus station,” notes Vladimír Ždímal, head of the environmental engineering department at the Institute of Chemical Processes of the Academy of Sciences of the Czech Republic.
The Road Transport Inspectorate has also been measuring emissions from cars directly on the road for almost a year. It has two fully equipped cars for this purpose. So far, the inspectors have checked 165 drivers and found defects in almost every fourth one.
Airborne dust has the greatest impact
Emission concentrations are monitored mainly on busy roads in cities. Exhausts, i.e. sources of pollution, are low to the ground and therefore close to people. Airborne dust has the greatest impact on health. Dust particles are not even visible to the naked eye. Their size is measured in micrometers, which are ten-thousandths of a centimeter. Compared to a human hair, which has an average diameter of about 70 micrometers, the finest dust particles commonly monitored are almost thirty times smaller.
This also makes them dangerous because they penetrate deep into the alveoli of the lungs. And some even into the bloodstream. Dust, especially from diesel engines, is also carcinogenic. Its long-term elevated concentrations increase the risk of cancer and heart and blood vessel disease. The particles can also worsen asthma and contribute to more frequent respiratory infections.
The average age of European cars is less than thirteen years, but on domestic roads it is more than sixteen years. Only Estonia and Greece are worse off. The older the vehicle, the more deficiencies need to be addressed during regular inspections at technical inspection stations (STK). Regular maintenance is key.
The European Union is now dealing with inspections at technical inspection stations. It originally wanted cars over ten years old to have to be inspected every year, but members of the transport committee rejected this. Proposals to make it mandatory to record mileage during service visits, to have all assistance systems functional, and to have emissions measured remotely remained in play.
“This kind of thing already exists today, but the diagnostic interface is not installed on anything, it has no transmitter that would send the values somewhere. If this could be expected in series production, such a vehicle would be able to continuously send (information about this, note) whether all its systems are in order and how those systems are working dynamically,” explains Libor Fleischhans, chairman of the Association of Emission Technicians and Repairers.
The activities of the MOT are supervised by the Ministry of Transport. Under the previous leadership, it had an audit prepared and in recent years it has itself conducted twenty so-called honesty tests. It then called for further inspections by regional authorities. They carried out five hundred checks and found errors in one hundred and forty technicians. However, according to some experts, the real numbers may be even higher.
“From the ISTP (Information System for Technical Inspections) data, it follows that new types of strange circumstances, frauds, and errors can be found again and again. (...) It follows that there are many tens of thousands of cars, perhaps hundreds of thousands of cars that have passed emission checks, have an emission report, and that report does not contain true information,” notes Petr Novák, a data analyst at the Association of Emission Technicians and Repairers.