An orange balloon floated 50 feet above California State University, Fresno's small dairy herd last week, helping in the unsavory task of gathering air samples from a plume of pungent gases.
On the ground, a gas chamber held more samples as Holstein and Jersey cows munched feed nearby. Researchers sweated in the barnyard stench, ensuring sampling instruments worked properly.
It's not glamorous, but this is the cutting edge of air-quality science. In just the past decade, dairies have emerged as a serious source of air pollution, and there's work to do.
Fresno State is among 10 universities around the country studying every aspect of the gases coming from the multibillion-dollar industry.
What chemicals comprise these gases? What can be done to limit them?
For good reason, the scientists at Fresno State are among the research leaders. The San Joaquin Valley is the nation's most productive dairy region, with about 2 million milking cows.
Until now, no researcher had used a balloon to track the gases as they move away from a dairy, said Segun Ogunjemiyo, a Fresno State geography professor and one of the lead investigators.
"Are the gases diluted as they move?" he asked. "Do they disperse? Are there other chemical reactions taking place?"
The research is important because of a major misconception about dairy emissions. Five years ago, government officials thought most of the pollution gases came from cows and their waste.
But University of California at Davis researchers this year found that the biggest source of emission at a dairy comes from feed, such as fermenting corn silage.
It is considered a significant problem. Dairies create almost twice as much reactive organic gas as cars do in the valley, according to recent studies.
The gases cook together with nitrogen oxides from vehicles and other combustion sources, such as fires, to make ozone in the valley, one of the nation's most polluted air basins.
Fresno State researchers are trying to determine if dairies cause problems on a regional basis, not just around the farm.
The research will help in designing rules and emission controls, say state and valley air-quality officials. For instance, completely covering feed piles might help reduce gases.
Ogunjemiyo is working with Alam Hasson, a chemistry professor at Fresno State, and Steven Trabue, a federal scientist who works with Iowa State University. They obtained a $600,000 grant from the U.S. Department of Agriculture for a three-year valley study.
The money came from more than $5 million in fed-eral grants to 10 universities across the country for such research. The other schools include the University of Minnesota, Ohio State University and Texas Tech University.
At Fresno State, the latest innovation is using the $100,000 orange balloon, purchased with a grant from the federal National Science Foundation.
It looks like a miniature dirigible. Filled with helium and attached to a nylon line, it takes instruments aloft to measure wind speed and collect air samples for later analysis. The instruments are operated by remote control, and data are transmitted to receivers on the ground.
Hasson said the team spent three months setting up the work with the balloon. The researchers will go into the lab over the next several weeks and begin analyzing the gases.
One complication is that the gases from the Fresno State dairy mingle with emissions from traffic. So the next step will be to analyze a dairy away from the city.
"April is the next time we will be sampling," Hasson said. "There are many different kinds of dairies, so we will try to find one that is representative of many dairies."
The professors said there are 14 students involved in the research.