Study: Diesel Vehicle Particulate Matter Small, Declining
The nation’s diesel engine lobby is pointing to the release of new research that shows diesel emissions are often wrongly blamed for causing too much pollution and diseases, while recent efforts to curb them is often misunderstood.


The nation’s diesel engine lobby is pointing to the release of new research that shows diesel emissions are often wrongly blamed for causing too much pollution and diseases, while recent efforts to curb them is often misunderstood.
A new paper issued by the United Nations Economic Commission for Europe concluded that diesel road vehicles were the cause of only a small percentage of particulate matter in Europe and the United States compared to economic sectors like the commercial, institutional and household sectors, according to the Diesel Technology Forum.
“From the data and facts mentioned above, we conclude with a high degree of reliability that it is misleading to claim that people’s exposure to diesel engines of road motor vehicles is the cause of increased risk of lung cancer,” UNECO concluded in the paper entitled “Diesel Engine Exhausts: Myths and Realities”.
“Eighty three percent of particulate matters emissions in European Union countries and 97% in the United States of America and Canada is generated by other economic sectors, mainly the commercial, institutional and household sector,” the paper concluded. “Therefore, the claim that emissions from diesel engine exhausts from road transport are the main cause of lung cancer in humans needs to be seriously challenged. It does not mean however, that measures to improve the environmental performance of the transport sector can stop. On the contrary, they must continue and in an aggressively well targeted way.”
UNECE is one of five regional commissions of the United Nations with the major aim of promoting pan-European economic integration. It brings together 56 countries located in the European Union, non-EU Western and Eastern Europe, South-East Europe, the Commonwealth of Independent States (parts of the former Soviet Union) and North America.
This UNECE paper highlights the positive trends in reducing emissions from new clean diesel technology as well as the misperceptions about the overall role of diesel engines in air pollution,” said Allen Schaeffer, executive director of the Diesel Technology Forum.
He said the development of new clean diesel technology for passenger vehicles, trucks, buses, construction and farm engines have reduced particulate matter and nitrogen oxide emissions by more than 90% in the past two decades.
“The UNECE paper provides an important perspective often overlooked in the environmental debate, that diesel vehicle engines have dramatically improved their emissions and are not a significant cause of particulate matter emissions in developed countries. It also highlights the importance of diesel technology for developing countries and how to improve air quality through harmonized global fuel and emissions standards,” said Schaeffer.
The Diesel Technology Forum says the new UNECE report has similar findings to a separate study published in the journal Nature Communications on May 13.
According the forum, it found that in many Asian and European communities cars and trucks, particularly diesel vehicles, are thought to be the main vehicular pollution sources, but that needs re-thinking.
“As we show that elevated particulate matter levels can be a consequence of ‘asymmetric pollution’ from two-stroke scooters, vehicles that constitute a small fraction of the fleet, but can dominate urban vehicular pollution through organic aerosol and aromatic emission factors up to thousands of times higher than from other vehicle classes,” the report said
More Equipment

What It's Like Inside this Custom 2025 Peterbilt 589?
Take a driver's-eye tour of this customized 2025 Peterbilt 589 as longtime driver Ingrid Brown explains its features, compares it to previous models, and shares plenty of personality along the way.
Read More →Drivers Put Western Star Trucks to the Test at Star Nation Experience
Watch to get an inside look at the Western Star trucks, technology, and community behind the Star Nation Experience 2026!
Read More →
Atlas Expands Kodiak Driverless Truck Fleet in Permian Basin
Atlas Energy Solutions is expanding autonomous frac sand hauling in the Permian Basin with a second load-out location and plans for 100 driverless trucks by mid-2027.
Read More →
Putting Mack’s Command Steer to the Test
A test drive of Mack’s Command Steer active steering system evaluates how it can make truck driving easier and less tiring.
Read More →
Mack, Volvo Expand DEF Derate Software Updates
The updated software gives Mack and Volvo truck owners more time to address DEF-related issues before the engine derates or the vehicle goes into reduced-speed inducement, following new EPA guidance.
Read More →
Rush, MCT Team Up to Grow Refrigeration Service Network
The joint venture will operate MCT's network of Carrier Transicold dealerships and mobile service locations, with the companies promising greater service capacity and uptime for refrigerated fleets.
Read More →
Cummins Adjusts 2027 Engine Rollout After EPA Proposal
The engine maker will gradually introduce its new Model Year 2027 diesel engines while continuing to offer current models during the transition, citing the EPA's proposed emissions rule changes.
Read More →
Aurora Rolls Out Next Generation of Driverless Trucks for Commercial Freight
Aurora's latest autonomous trucks it's rolling out with International feature lower-cost hardware designed for a million miles as the company expands commercial driverless freight operations across the U.S. Sun Belt.
Read More →
Peterbilt 589 Spotlight: A Close Look at a Custom Working Truck [Video]
There's more to this customized Peterbilt Model 589 and Great Dane refrigerated trailer than chrome and stainless (although there's plenty of that too!) A veteran driver explains the design choices and practical features behind this working truck.
Read More →
Continental Expands Retread Lineup With New ContiTread HDL 5 EP
New long-haul drive retread is designed to improve fuel efficiency, extend tread life, and lower fleets' cost per mile.
Read More →
