Researcher measures the gases cows emit

updated 9:32 a.m. ET July 28, 2005

DAVIS, Calif. - In a white, tent-like "bio-bubble" on a farm near Davis, eight pregnant Holsteins are eating, chewing and pooping — for science.  "The ladies," as they're called by University of California researcher Frank Mitloehner, are doing their part to answer a question plaguing one of California's largest agricultural industries: How much gas does a cow emit?

The findings will be used to write the state's first air quality regulations for dairies and could affect regulations nationwide.

But before he explains how it works, Mitloehner wants one thing to be clear.  "We're not talking about flatulence," he says.

He emphasizes the point because his research has been dismissed as "fart science," a label he says doesn't do justice to the seriousness of his work.

There are more than 3 million cows in California, the vast majority living in the booming Central Valley, home to some of the most polluted air in the country.  How much to blame the cows and how much to blame the cars for the bad air is no small concern.

Mitloehner's research has suggested that cows are responsible for far fewer of the compounds that contribute to smog, known as volatile organic compounds or VOCs, than previously thought, perhaps as little as half the amount.

That puts the air quality specialist and animal emissions expert in the middle of a heated dispute coming to a head Aug. 1, when the San Joaquin Valley Air Pollution Control District will announce its new emissions factor for cows— the amount of VOCs, in pounds, that a cow releases each year.  The number will eventually determine which dairies must apply for air quality permits and invest in mitigating air pollution equipment.

"This is a multibillion decision," said Mitloehner.  "It's not just a number."

Currently, regulators assume that a cow produces 12.8 pounds of VOCs a year.  But regulators, environmentalists and many in the $4 billion dairy industry agree that the current emission factor, which is based on a 1938 study, is out of date.

A regulator for the air control district has proposed an increase to 20.6 pounds per cow. Industry groups estimate that number is around 5 pounds.

Mitloehner says he just wants to make sure the new number is based on science.  His solution was to recreate a cow's living conditions in a modern dairy and then seal it off.

MORE FROM SCIENCE

Science Section Front

Vanished Persian army said found in desert What your Facebook photo says about you Expert: Separate pandas to rekindle affection Cosmic Log: DNA barcodes make their mark Did Neanderthals have sex with modern man? British scientists challenge government Antarctic lakes loaded with mysterious viruses Military drones enlisted as climate scouts Before flowers, odd bugs pollinated plants Study: Nanoparticles can damage DNA Science Section Front   Add Science headlines to your news reader: