EURO6 wont solve the Problem with Particulate Emissions
On January 1st, 2013—long before the diesel emissions scandal made headlines—the EURO 6 emissions standard came into force for trucks and buses over 3.5 tons. This significantly tightened particulate‑matter limits. In addition, for the first time, regulators began measuring not only particle mass but also particle count.
One might assume this solves, or at least substantially mitigates, the emissions problem.
Far from it. When it comes to particulate matter—and I will limit myself strictly to particulate matter here—there is even more manipulation than in the diesel scandal, which until now has been perceived mainly as an issue in the passenger‑car segment. The difference is that this time it is not done through defeat devices (at least none we know of), but through loopholes in regulations and inadequate measurement technology.
Particulate matter has traditionally been measured only for particles of 10 micrometers and larger. This has since been refined to include particles of 2.5 micrometers. Hence the rule that not only particle mass but also particle count must be measured.
You should be aware that particulate matter from diesel exhaust becomes increasingly dangerous as particle size decreases. In other words, the smaller the particle, the more harmful it is when inhaled. Put simply: one thousand particles at 2.5 micrometers are significantly more dangerous than one thousand particles at 10 micrometers. Smaller particles penetrate much deeper into the human body.
Why should this concern you?
Unfortunately, the progression toward ever‑smaller particles does not stop at 2.5 micrometers. Modern EURO 6 diesel engines operate with very high pressures and very high temperatures. Earlier diesel engines avoided extreme temperatures because they dramatically increased nitrogen oxide production. Under EURO 6, however, NOx limits are so low that an SCR system (urea injection) is mandatory. This largely resolves the NOx issue—at least when the SCR system is actually active, which, as news reports have shown, is often not the case.
High temperatures and pressures not only increase NOx formation but also generate much smaller particles—far smaller than 2.5 micrometers. Particle sizes reach down into the single‑digit nanometer range. For comparison: one millimeter consists of 1,000 micrometers and one million nanometers. A 10‑nanometer particle is therefore 250 times smaller than the lower measurement threshold. Another comparison: if a 10‑nanometer particle were the size of a 1‑centimeter grape, the lower measurement threshold would be roughly 2.5 meters—larger than a human being.
Why is this a problem? One would assume these particles are accounted for in mass measurements. Unfortunately, they are not. Current measurement methods are unreliable in the nanometer range; anything below 70 nanometers is effectively invisible to them. This means diesel engine manufacturers only needed to make particles small enough that they could be detected only by specialized laboratories. Unfortunately, these particles are highly toxic. We are no longer talking merely about lung cancer or asthma—we are talking about severe heart attacks, strokes, and advanced dementia.
Your heart attack might come from too many schnitzels per day—but just as easily from the particulate matter you breathe daily. Your pollen filter system offers no protection here. Below 70 nanometers, these particles behave as aerosols—solid matter that behaves like a gas. They remain almost permanently suspended in the air we breathe and bypass all barriers. In the end, nano‑particulate pollution is highly democratic: you cannot protect yourself from it, except by not producing it in the first place.
This would require a substantial reduction in the use of diesel and gasoline.
LNG (natural gas) produces no particulate matter during combustion, just like electric vehicles. Since it functions similarly to diesel—without generating this pollution—and is equally economical, the problem could be resolved cleanly and efficiently. The question is: is our survival instinct strong enough?