Studies support efforts to reduce diesel exhaust air pollution

Another post for my friend Rob...

Two real-world studies from Europe demonstrate the health damage done by automotive air pollution, especially the kind emitted by diesel engines.

 

An 11-year period of improving air quality in Switzerland, which started with some of the cleanest air in Europe, produced measurable benefits in lung function for adults as they aged, according to a report in the Dec. 6 issue of the New England Journal of Medicine.

"Even with small improvements in air quality, you get measurable health benefits," said Dr. Ursula Ackermann-Liebrich, a professor of public health at the University of Basel. "That is true at levels even which are quite low."

 

And an unusual collaborative study by American and British researchers, reported in the same issue of the journal, showed that people with asthma who walked along a street used by diesel-powered traffic experienced loss of breathing much greater than those who strolled through a traffic-free park.

 

"The unique feature of this study in real-world conditions was that we have demonstrated that typical urban levels of air pollution with diesel-rich powered vehicles have measurable effects," said Dr. Junfeng Zhang, chairman of environmental and occupational health at the New Jersey School of Public Health and an American member of the research team. "There have been theories or hypotheses of diesel exhaust or particle matter and also laboratory studies with animals, but this was a study in the real world with real people."

 

The Oxford Street walk produced a 5 percent to 6 percent reduction in lung function, "and asthmatics already have compromised lung function," Zhang said.

 

The reduction in lung function was "significantly larger" than what was measured after the Hyde Park walk and was accompanied by an increase in biomarkers of lung inflammation. The negative effect on the lung was greater than has been seen in animal studies using breathing chambers, Zhang said.

 

The Swiss study found a decrease in the amount of airborne fine particulate pollutants, a major feature of diesel emissions. That improvement in Swiss air quality was accompanied by a slowing in the rate of the loss of breathing function that occurs as people age, Ackerman-Liebrich said. The journal report attributed the healthful effect to "decreasing exposure to airborne particulates."

 

"There seems to be something more potent than other forms of air pollution in diesel exhausts," said Dr. Morton Lippman, a professor of environmental medicine at New York University. "It is something many other studies have pointed to."

 

The issue of diesel pollution is of growing interest because "new diesel technologies are increasingly coming on the market," Lippmann said. Diesel automobiles are much more common in Europe than in the United States but are gaining attention because of their greater fuel efficiency, he noted.

 

The two studies are welcome because they assess the effect of diesel emissions at relatively low levels, Lippmann said. "That remains a complex issue," he said. "Getting statistically significant information on a small average effect on a large population is not easy. There are a lot of unknowns. Most effects are associated with particles rather than gases in the mixture, but there is no data on which part of the components is particularly nasty."

 

 

A national program for cleaner diesel emissions is described by the U.S. Environmental Protection Agency.

Reducing emissions from diesel engines is one of the most important air quality challenges facing the country. Even with more stringent heavy-duty highway engine standards set to take effect over the next decade, over the next twenty years millions of diesel engines already in use will continue to emit large amounts of nitrogen oxides and particulate matter, both of which contribute to serious public health problems. These problems are manifested by thousands of instances of premature mortality, hundreds of thousands of asthma attacks, millions of lost work days, and numerous other health impacts.

Building on the successes of EPA's regulatory and non-regulatory efforts to reduce emissions from diesel engines, EPA has created the National Clean Diesel Campaign (NCDC). The Campaign will work aggressively to reduce the pollution emitted from diesel engines across the country through the implementation of varied control strategies and the aggressive involvement of national, state, and local partners.

NCDC participants are committed to reducing diesel emissions and finding innovative ways to protect human health and the environment. To fully address the challenges of reducing diesel emissions the NCDC is using a multi-pronged approach:

• Commitment to the successful implementation of the Clean Air Highway Diesel Rule (the "2007 Highway Rule") and the Clean Air Nonroad Diesel Rule.
• Developing new emissions standards for locomotive and marine diesel engines.
• Promoting the reduction of emissions for existing diesel engines through cost-effective and innovative strategies, including use of cleaner fuels, retrofitting and repairing existing fleets, idling reduction among others.

 

Programs for the Existing Diesel Fleet

Over the last five years, EPA has brought forward a number of very successful innovative programs all designed to reduce emissions from the diesel fleet. In conjunction with state and local governments, public interest groups, and industry partners, EPA has established a goal of reducing emissions from the over 11 million diesel engines in the existing fleet by 2014. Looking at these engines, EPA determined there were general sectors that provided the best opportunity to obtain significant reductions. In addition, school buses were identified as an area where diesel emission control can greatly help a susceptible population. These sectors are school buses, ports, construction, freight, and agriculture. Each program provides technical and financial assistance to stakeholders interested in reducing their fleets' emissions effectively and efficiently.

 

Regulations for Clean Diesel Engines and Fuels

The Agency is devoting significant efforts to ensuring the successful implementation of stringent new standards for diesel fuel and new diesel engines. These standards are the critical foundation of EPA's diesel control program.

Beginning June 1, 2006, refiners must begin producing clean ultra-low sulfur diesel fuel- diesel fuel with a sulfur level that is at or below 15 parts per million (ppm)- for use in highway diesel engines. Low sulfur (500 ppm) diesel fuel for nonroad diesel engines will be required in 2007, followed by ultra-low sulfur diesel fuel for these machines in 2010, and for locomotives and marine engines in 2012.

Besides reducing emissions from the existing diesel fleet, these clean fuels will enable the use of advanced aftertreatment technologies on new engines. Technologies like particulate traps, capable of emission reductions of 90% and more, will be required under new standards set to begin phasing into the highway sector in 2007, and into the nonroad sector in 2011. These programs will yield enormous long-term benefits for public health and the environment. By 2030, when the engine fleet has been fully turned over, PM and NOx will be reduced by 250,000 tons/year and 4 million tons/year, respectively. This will result in annual benefits of over $150 billion, at a cost of approximately $7 billion. Similar stringent emissions standards for locomotives and marine diesels are now being developed. EPA is also working to reduce emissions from large commercial marine diesel vessels like cruise and container ships through the use of cleaner fuels and engines.

Together these programs will yield enormous long-term benefits for public health and the environment.