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May 19, 2016   |   Diesel Technology Forum

Policy Insider

Breathing Easier With Clean Diesel

The transition to near zero emissions diesel technology not only contributes to cleaner air but also provides health benefits.

Relative to decades ago, our air is much cleaner. The iconic cover of Time magazine back in 1967 saw L.A. shrouded in a hazy cloud of fine particles and smog such that visibility was constrained to just a few feet. Air quality in other major metropolitan regions was not much better. Since then, decades of innovation in cleaner fuels and emission control technologies have dramatically improved our air quality. Since that cover of Time magazine was published in 1967, gasoline and diesel fuel is much cleaner. Modern engine designs and tailpipe emission control technologies have exponentially reduced emissions. Clean diesel technology has been a major contributor to our cleaner air. The recent “State of the Air” report issued by the American Lung Association noted that the transition to cleaner diesel engines is attributable to improvements in clean air. One of the most easily identifiable applications of diesel is a tractor-trailer seen on our roads and highways. A Class 8 diesel tractor that meets the most recent tailpipe emissions standard set for model year 2010 results in 98 percent less emissions of oxides of nitrogen (NOX), a smog forming compound, and particulate matter (PM), than a truck manufactured in 1988. The transition to near zero emissions diesel technology not only contributes to improved visibility but also provides health benefits.

The real benefit of cleaner air is more than just visibility but public health. Here again, clean diesel technology has been a major contributor in improving public health. Fine particles emitted from a variety of sources including dust, forest fires, powerplants and internal combustion engines have been linked to adverse health effects including lung ailments. Clean fuel and the first near-zero emissions engine standards for commercial vehicles, established for model year 2007, have reduced fine particle emissions from diesel trucks. If a penny weighs 2.5 grams, a 30,000 lbs Class 8 tractor powered by a model year 2007 compliant engine hauling 50,000 lbs of freight would need to travel 100 miles before generating a penny’s weight in particulate matter. A truck manufactured in 1988 would need to travel just 10 miles before generating a penny’s weight in PM.

Recent research suggests that diesel engines that meet the near-zero particulate matter standard established for model year 2007 result in no significant adverse health effects. Laboratory animals exposed to emissions from these clean diesel engines displayed no impaired lung function and no noticeable adverse effect on lung tissue. In fact, recent diesel engines manufactured in 2011 analyzed in an earlier phase of research in the study, were found to emit far less particulate matter emissions than required by regulation. This study provides strong evidence that clean diesel engines on the road today do not contribute to adverse health outcomes.

While the Clean Air Act is almost 50 years old, the transition to cleaner fuels, engines and emission controls on cars and trucks is almost equally as old.  The transition to clean diesel fuel and engines may be the latest chapter in the Clean Air Act and there is strong evidence that engines developed to meet strict near-zero emissions requirements clean the air but more importantly provide public health benefits.  


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Ezra Finkin
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