For years, the conventional wisdom has been that pollution from diesel engines was far worse than from gasoline engines for two reasons: First, diesel exhaust fumes are known to contain nitrous oxide emissions. Second, they also contain particulates, small molecules that are too small to see. Both are believed to cause serious damage to human lungs.

Particulate Emissions From Gasoline Engines

Now it turns out that conventional wisdom is wrong. A study by researchers at the Materials, Science, and Technology Laboratory in Switzerland claims that particulate emissions from gasoline engines can be far greater than those from diesel engines.

The laboratory studied the emissions of 7 gas engine vehicles equipped with direct-fuel-injection systems. The research found that they emit from 10 to 100 times more particulates than modern diesel engines. In fact, they have higher particulate emissions than older diesel without particulate filters.

Wait, did you read that right? Gasoline engines spew out up to one hundred times more particulates that a modern diesel engine equipped with a particulate filter? Yes, you read that right. Yikes. And people wonder why the incidence of asthma and other lung related diseases is on the rise!

Researchers Find Carcinogens In Gas Engine Exhaust

The researchers, led by Norbert Heeb, who has 25 years of experience analyzing emissions from diesel engines and designing filter systems, showed that the particles are the same size as those from older diesel engines. They measure between 10 and 20 nanometers and clump together into particles between 80 and 100 nanometers before they leave the exhaust system.

The gas engines were also found to discharge unburned hydrocarbons in the form of polycyclic aromatic hydrocarbons (PAHs), along with other liquid and solid toxins which accumulate on the surface of the emitted particles.

Particulates Penetrate The Lungs

Heeb says the particles are so small they penetrate lung tissue and pass into the bloodstream, bringing those toxins with them. Is this beginning to sound like the days when researchers first told the world about all the nasty stuff contained in cigarette smoke? It should, because it turns out there is a connection to smoking. The researchers also found that the exhaust gasses coming out ot the tailpipes of the cars with gas engines also contain benzo-α-pyrene, a carcinogenic produced when tobacco is burned.

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