Diesels Linked to Clogged Arteries

What does breathing in diesel smoke have in common with the side of cheese fries you might have recently had for lunch? They both, in any regularity, might increase your chances of heart disease.

In a new report published last week in the journal Genome Biology, a group of UCLA scientists studied the biological process in which particulate matter in diesel exhaust interacts with fatty acids in LDL cholesterol (the “bad” number your doctor wants you to keep down) to cause blood-vessel inflammation and accelerated rates of atherosclerosis — the plaque-building mechanism that leads to heart disease.


The new study’s laboratory work coincides with observational data gathered in various studies finding that people living near diesel pollution sources had higher instances of heart disease.


The study said that recent data had implicated air pollution as a risk factor for developing the heart disease. It joins family history, activity, smoking, hypertension, age, gender, and diet, all widely attributed as risk factors. Heart disease is the leading cause of death in the Western world.


The scientists said that exposure to the smallest particles in particulate matter seem to have a greater impact in plaque formation than the larger ones. In mice, the study found that exposure to diesel particulate matter in what is termed the ultrafine size range (less than 0.18 micrometers) resulted in an increase in atherosclerotic lesions.


Particulate matter in the U.S. is regulated by overall mass, not particle size, so there is no conclusive assessment of whether so-called clean diesels actually reduce the number of ultrafine particles, or whether they merely remove the larger particles that might approach what’s commonly identified as soot.


Sam Atwood, a spokesman for the South Coast Air Quality Management District, the air pollution control agency for much of Southern California, said that the self-regenerating particulate filters being used on heavy-duty vehicles have been shown to reduce the number of ultrafine particles in the exhaust, along with overall particle mass. Atwood added that ultrafine particles are likely present at some level in all engine exhausts.


However, Atwood pointed to a 2005 USC study that observed while the overall mass of particulate emissions has gone down over the years, the number particles emitted — an indicator of ultrafine particles — has gone up.


This, combined with other health concerns pertaining to ultrafine particles (a number of health organizations already conclude that these smaller particles have a greater impact on the lungs and in respiratory issues), may indicate the need for a different set of emissions rules altogether for diesels.


In California, where the rules are strictest for diesels, the current particulate matter standard for passenger car and light truck diesels is 0.01 grams per mile. Federally, it has been ten times that, 0.10 grams per mile, although several automakers say that they will meet the stricter California standards this next year. For medium-duty trucks, the current limit is 0.06 g/mi. Heavy-duty vehicles, such as semis and buses, are regulated on the basis of engine power; the current federal limit is 0.01 grams per bhp-hour, which has been phased in for the 2007 model year.

Related Articles


Mercedes Preps DiesOtto Engine by Richard Yarrow (7/26/2007)
New engine blends gas, diesel features.


GM Teams with Penske for Diesels by Joseph Szczesny (7/22/2007)
New Cadillac Eurodiesel first fruit of deal.


Jetta Gets Clean Diesel TDI in ‘08 by Henny Hemmes (6/26/2007)
Sedan will be the first model with clean diesel engine.

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