The Beat

Environmental Health Perspectives, April, 2000

Organic Power

A demonstration project conducted by the USDA Agricultural Research Service has found that diesel vehicles such as trucks, tractors, and buses can run more cleanly if organically based biodiesel is mixed with the regular diesel fuel. "B20" fuel (which is 20% biodiesel, derived from soy or other seed oils or animal fat) requires no engine modifications in order for it to be used.

Alan Weber, a representative of the National Biodiesel Board, says that credits for biodiesel fuel use are available to federal and state agencies and public utilities in large metropolitan areas under the 1992 National Energy Policy Act. One of the goals of the USDA project, part of a federal initiative to reduce dependence on petroleum-based fuels and build new markets for U.S. crops, is to increase the federal government's use of bio-based fuel by 10% over the next five years.

Country Roads Not Always Cleaner

A new method of measuring road dust developed by researchers at Washington University's Air Quality Laboratory in St. Louis reveals that the average rural vehicle creates over six times more particulate matter (PM) than the average urban vehicle. The acidity and high volume of PM emissions, along with their heavy metal composition, may lead to such health effects as upper respiratory illnesses, cardiovascular disease, and cancer.

The new method measures the net sum of PM emissions created by a vehicle by several means over each mile it travels, focusing on particles smaller than 2.5 microns in diameter. Using this method, regulatory and government agencies can more accurately measure particulate emissions and then strategize to reduce them.

Texans Bogged in Smog

Houston, Texas, must take strong measures to reduce its air pollution--cited as the worst in the United States--in order to comply with federal ozone standards, states a 23 December 1999 article in the Fort Worth Star-Telegram. The article reports that 75 measures, including restricting driving on every fourth day and reducing the highway speed limit to 55 miles per hour, were proposed during a December meeting of Texas environmental officials.

To comply with federal law, Houston must reduce vehicle miles traveled by 25% and industrial nitrogen oxide emissions by 90%, but petrochemical industry emissions, along with those from automobiles and port traffic, are making this difficult. Texas commissioner Ralph Marquez said that even the measures proposed may not be enough to bring Houston in line with the Clean Air Act, which requires the city to meet federal ozone standards by 2007.