Petroleum Diesel Health Research

Switch to Biodiesel Fuels Workplace Improvements

Devil in the diesel: Lorries belch out what may be
the most carcinogenic chemical ever discovered.

Sick of Soot: Reducing the Health
Impacts of Diesel Pollution in California

Switch to Biodiesel Fuels Workplace Improvements
Heavy industry requires heavy equipment, but the diesel exhaust from these machines can create an unpleasant, potentially unhealthy, work environment. Reducing diesel exhaust exposure is one of Alcoa's health focuses, and this commitment can be seen at the company's Davenport Works in Iowa.

The almost 100 diesel fork-trucks and 40 pieces of heavy equipment that keep this plant running smoothly consume 250,000 gallons of fuel each year. In 2002, the plant switched from diesel fuel to a soy-based biodiesel that greatly reduces exhaust particulate and other emissions from the equipment. Before the switch, employees around the diesel exhaust frequently complained of eye, throat, and respiratory irritation.

"The particular area where I work is well confined with little ventilation," said Ron Pritchard, equipment operator in Davenport's ingot plant. "In the winter when everything was closed up, it became very unpleasant. We had to keep the door open about a foot to keep the fumes moving."

Eliminating diesel equipment wasn't feasible because of the limited capacity of alternative equipment, such as electric-powered vehicles. In 2001, Davenport began evaluating biodiesel, a renewable energy source made from a variety of natural oils. The selected fuel, known as B20, is a 20% blend of soy-based biodiesel and low-sulfur diesel. This blend can be used in new and older diesel engines with no engine modifications and no noticeable impact on the engine's operating performance. The fuel, which is slightly more expensive than diesel, also can prolong engine life.

Results of the evaluation indicated that the ambient concentration of diesel exhaust particulate in high traffic areas decreased 80%. Tailpipe emissions were reduced by 44.2%, and additional benefits included a reduction in hydrocarbon, sulfur dioxide, carbon monoxide, and carbon dioxide emissions. In addition, the objectionable odor of diesel exhaust changed to the odor of French fries.

In 2002, Davenport switched from diesel to biodiesel for all powered equipment. The change, which involved no additional expense, reduced employee health risks, decreased the use of fossil fuels, and reduced emissions into the environment.

"After we switched to the new fuel, the air cleared up quite a bit," said Pritchard. "We don't have the burning eyes and throats like we used to."

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Sick of Soot: Reducing the Health Impacts of
Diesel Pollution in California

Diesel soot, or particulate matter (PM), is a dangerous pollutant that can penetrate deep into the lungs. People exposed to diesel soot can suffer from severe respiratory and cardiovascular illnesses, chronic bronchitis, cancer, and premature death. California, with the largest population of people and diesel vehicles in the country, is in essence a microcosm of the national health risks of diesel emissions.

Soot: A California Killer
In 2000, the California Air Resources Board (CARB) estimated that diesel PM was responsible for 70 percent of the state’s risk of cancer from airborne toxics (CARB, 2000c). Diesel engines often remain in operation for decades, with the older engines releasing the greatest amount of pollution. In 2004 alone, diesel pollution will cause an estimated 3,000 premature deaths in California—greater than the estimated 2,300 annual homicides in the state.1 In addition, diesel exhaust will cause an estimated 2,700 cases of chronic bronchitis and about 4,400 hospital admissions (including emergency room, or ER, visits) for cardiovascular and respiratory illnesses every year. The cost of these health impacts is $21.5 billion per year.

While Californians in every corner of the state are exposed to diesel pollution, the most densely populated and polluted air basins have the highest number of health problems. Roughly 90 percent of California’s population, and 80 percent of the state’s diesel pollution sources, are found in 5 of the 15 air basins: Sacramento Valley, San Diego, San Francisco Bay Area, San Joaquin Valley, and South Coast. This sets an important example for population centers nationwide.

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Devil in the diesel: Lorries belch out what may be
the most carcinogenic chemical ever discovered.
New Scientist, 25 October 1997

A COMPOUND discovered in the exhaust fumes of diesel engines may be the most strongly carcinogenic ever analysed, say Japanese researchers. They warn that a major source of the chemical is heavily loaded diesel-engines, and that it could be partly responsible for the large number of lung cancer cases in cities.

The compound, 3-nitrobenzanthrone, produced the highest score ever reported in a Ames test, a standard measure of the cancer-causing potential of toxic chemicals.

“I personally believe that the recent increase in the number of lung cancer patients in vehicle-congested areas is closely linked with respirable carcinogens such as 3-nitrobenzanthrone”, says Hitomi Suzuki, a chemist at Kyoto University who led the study. Test emissions from truck engines and the air above central Tokyo both contained the compound.

3-Nitrobenzanthrone is a nitrated polycyclic aromatic hydrocarbon (nitro-PAH).It is produced during reactions between ketones - by products of burning fuel - and airborne nitrogen oxides that take place on the surface of hydrocarbon particles in diesel exhaust.
The researchers used the Ames test to measure the number of mutations the compound caused in the DNA of standard strains of bacteria. In a test with a strain of Salmonella typhimurium, 3-nitrobenzanthrone recorded more than 6 million mutations per nanomole. This compared to a score of 4.9 million for its nearest rival, 1,8-dinitropyrene, which is also found in diesel exhaust and had until now been the most powerful known mutagen.

In a further experiment, the researchers found that the compound caused “considerable chromosomal aberrations” in the blood cells of mice, suggesting that it is likely to have similar effects on other mammals, including humans. Suzuki and colleagues from the National Institute of Public Health in Tokyo and the Kyoto Pharmaceutical University report their findings in the October issue of Environmental Science and Technology (vol 31, p 2772).

The two mutagens are found only in minute quantities. Each makes up no more than a few parts per million of the particulates in diesel exhaust. Nonetheless, the Authors conclude that they are so toxic that “it is easily understandable that they would contribute considerably to the total mutagenic activity of diesel exhaust particle extracts."

Tiny combustion particles, many of them from diesel exhaust, have been estimated to cause 10 000 deaths in Britain and 60 000 in the US each year (“dying from too much dust”, New Scientist, 12 March 1994, p 12).

Tony Seaton of the Aberdeen Royal Infirmary, a leading adviser on air pollution and health to the British government, says: “PAHs are known carcinogens and nitro-PAHs are probably the worst. This one seems to be new to us.”

The Japanese study also provides clues about how to reduce the threat from 3-nitrobenzanthrone and other nitro-PAHs. It reveals a “remarkable increase” in emissions when engines are working under heavy load. This may show “the potential danger of engines overloading”, Suzuki says.

He calls for stronger regulations to limit the loads that diesel trucks can carry. In addition, nitro-PAHs are created faster in smoggy air with high levels of nitrogen oxides and ozone.

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