Everyone knew cars made these gases, but cows? Indeed, plumes of gases waft from San Joaquin Valley dairies where prodigious amounts of livestock waste are stockpiled. By 2005, cows will lead cars in venting this so-called "reactive organic gas," a main ingredient of smog.

MAJOR CONTRIBUTORS: Millions of tons of waste from the 1.1 million dairy cows in the Valley, like these at a Kings County dairy near Hanford, are flushed into large, uncovered lagoons. Until the 1990s, nobody knew that the waste created gases that add to the Valley's air problem. (Mark Crosse / The Fresno Bee)

But aren't dairies "mom and pop" businesses where owners live right next to their 80 to 100 cows? How could bales of hay, contented cows and a few pickup trucks make this kind of air pollution?

Because this is no "mom and pop" business anymore. Many dairies have more than 1,000 cows, and many are planned at more than 4,000 animals. The newest Tulare County dairy will have 14,000 cows. Two dairies in Kern County will have a combined 28,000 cows.

These mega-dairies, as environmentalists call them, present problems in winter, too. In the Valley's thick, tenacious fog, tiny particles form as ammonia and combine with other chemicals. The Valley's No. 1 source of ammonia is the dairy industry.

These little ammonia-based specks hang in the fog for hours and easily evade the body's defense mechanisms, penetrating deep into people's lungs. Such tiny particles are now being linked to high death rates and heart problems.

Welcome to the latest revelation nationally about air quality: Cows and other barnyard critters make air pollution.

How much? Enough to regulate the industry?

The debate is on – from North Carolina to the Pacific Northwest. About a dozen states are beginning to look at regulating cattle, dairy, pork, chicken and egg farms.

In California, the discussion centers around the $4.5 billion dairy industry. The keys are the tiny wintertime particles and an obscure 1938 study that is used as the basis for estimating cow gas emissions.

In the eight-county Valley, these issues hold great importance because the dairy industry flourishes here like few other places in the country. Tulare County is the top-producing dairy county in the nation with products worth $1.2 billion last year, and the rest of the Valley is no slouch either.

The Valley is home to an estimated 1.1 million dairy cows, which is about one-third of the size of the human population here. But if you throw in seasonal grazing herds, beef cattle and other bovine classes, more than 2.6 million cows live in the Valley at certain times of the year.

An adult cow expels 20 times more waste per day than a human.

The waste is concentrated in dairies where many cows are congregated in fairly small areas. Millions of tons of waste usually are flushed into large, uncovered lagoons where it decomposes. Until the 1990s, nobody knew it was an air problem.

"We didn't even list livestock waste in our inventory of emissions until the last decade," says Mark Boese, deputy air pollution control officer in the San Joaquin Valley Air Pollution Control District. "It just hasn't been an issue."

An accurate estimate of the gas emissions should be obtained before regulation is enforced, dairy industry advocates say. They criticize a 64-year-old methane study, which forms the basis of dairy smog projections and environmental impact reports on dairies.

The study, contained in a publication called "Nutritional Physiology of the Ruminant" from the Carnegie Institute, is far too old and off the mark, government experts agree. Additional research has been done, but it hasn't been substantial enough to replace the older work.

Citing sources dating back to 1890, the study concludes about 160 pounds of methane are emitted per cow each year. Methane does not make smog. The study does not investigate smog-making gases from cows.

But cows emit other gases that do form smog. These other gases account for about 8% of what cows emit.

Instead of measuring those gases, regulators have just been figuring 8% of 160 pounds, or 12.8 pounds of smog-making gases per cow each year. The smog-making gases include ethyl alcohol, ethyl amine, isoprophyl alcohol, propyl acetate and trimethyl amine.

But nobody knows if the 12.8 pounds is right.

"We have looked at other studies done in California, but they appeared incomplete and flawed," David Jones, Valley air district planner, wrote in an e-mail.

Dairy emissions controls have been put on hold until a National Academy of Sciences committee completes a study late this year. The study probably will suggest an approach to estimating emissions as well as a discussion of human health and environmental impacts.

Western United Dairymen, an industry group representing 1,100 dairies in the West and more than 700 in the Valley, agrees with the decision to wait on regulation. Michael Marsh, chief executive officer of the dairymen group, says the industry shouldn't be forced to clean up pollution that cannot be quantified.

But environmental lawyer Brent Newell of the Center on Race, Poverty and the Environment says the dairy industry's arguments are irrelevant. Large numbers of these animals can create an air problem, he says.

"We need to regulate first and apologize later," Newell says. "The people of this Valley are suffering from the air. There's no sense of urgency to clean this up."

The urgency should extend to the wintertime problem, too, Newell says.

Here's how the wintertime particles form: Ammonia combines with nitric acid, which forms from pollutants called nitrogen oxides that come from diesel trucks and cars. The combination makes tiny, potent specks known as ammonium nitrate.

Scientists call it PM2.5, which means particulate matter 2.5 microns wide. For comparison, a human hair is about 60 microns wide.

Medical science considers these particles a significant health hazard. The state Air Resources Board suspects 66,000 tons of ammonia annually rising from dairies is the main reason.

To environmentalists, these issues illustrate how the system failed to protect the public from dairies.

Newell's group and the Sierra Club filed a lawsuit about two years ago in Kern County to stop two dairies there with a combined 28,000 cows. The dairies finally gained approval in October. Newell may appeal.

His organization has taken action to hold up dairy expansion in several Valley counties. Most recently, Newell notified the Valley air district of his group's intention to sue over the lack of dairy regulation.

Newell believes the issues should first be handled at the planning level. He says such planning discussions are crucial because of the current dairy boom.

The burgeoning dairy industry is the biggest player in the state's formidable farming business, and large dairy operations are in vogue.

But it wasn't always so. In the 1950s, the state had almost 20,000 dairies, averaging 40 cows apiece. Last year, there were 2,157 with an average of 721 cows. More than half are in the Valley.

Why is the Valley becoming dairy Shangri-La? The inexpensive, wide open tracts of land have been very attractive to dairy farmers who were eager to leave congested Southern California.

So, just as many orange growers left Orange County for the Valley many years ago, Chino-area dairy owners have relocated to the Valley. And dairies have expanded to keep prices down, sales up and profits steady.

But, in their wildest dreams, no one would have imagined how large and controversial dairies would become. Three years ago, environmentalists and state officials began looking into the plans of farming magnate J.G. Boswell to build a series of Kings County dairies totaling about 50,000 cows.

Under fire, Boswell withdrew its plans two years ago, though the door still is open for the same proposals to surface again under many different owners. Yet environmentalists still are asking what would happen to the air with additional millions of tons of untreated cow manure from 50,000 cows.

Now, multiply that question about twentyfold for the more than 1 million cows in the Valley.

Indeed, what happens to the billions of pounds of manure annually produced by Valley dairies?

The manure is commonly stored in lagoons, which are cleaned out a few times a year, depending on the farmer's practices.

The waste often is used to fertilize crops for the cows to eat, or the dairy farmer might sell it to another farmer for use as fertilizer. Typically, a dairy will occupy many hundreds of acres with the animals congregated in a relatively small area where they are fed, milked and maintained.

The close confines create a pungent, highly concentrated brew of emissions, and they are attracting serious study now.

Michael Kenny, executive officer of the state Air Resources Board, says state officials are exploring feed options that will produce less waste. South Coast Air Basin in the Los Angeles area late this year will consider dairy controls that might include faster removal of the waste.

But there is a little-used technology that prevents air pollution while it uses animal waste to make electricity. It is called a digester, or methane-recovery system, which captures gases from the livestock waste and burns it to power an electricity turbine.

For one type of digester, the manure is incorporated into a process that turns it into a thick flow and sends it to a covered concrete pit. The manure slowly decomposes, making methane in the process.

The methane is captured by pipes to power the electricity generator.

But the systems can cost hundreds of thousands of dollars. Only a handful of dairies in California have them.

Western United Dairymen is working with the state on the new California Dairy Power Production Program, which can provide up to 50% of the money needed to build a digester. Nine projects have been approved for funding from the $10 million state grant program, according to Western United.

Without the program, the digester technology is too expensive, says Western United executive Marsh.

"These systems run up to $1.8 million," he says. "I'd say an average cost would be $500,000."

On top of the sticker shock, Marsh says dairy owners have had trouble selling their electricity to privately held utilities, such as Pacific Gas & Electric Co. and Southern California Edison Co., which face money and legal problems in buying from power producers.

Gov. Davis in September signed a law allowing dairies to get credit if their digester systems produce more power than their dairy uses from the utility. In other words, the dairy's billing meter would run backward and give the farmer a credit when it is producing extra power, which is fed into the state's central grid.

In the past, the electricity credit problems have made dairy farmers cool to the idea of digesters. The doubt lingers.

"There's a real hesitation to do it," says Doug Williams, a bioresource and agricultural engineering professor at California Polytechnic State University, San Luis Obispo.

Williams constructed a power-producing $225,000 system at Cal Poly. He says pollution reductions haven't entered the discussion for him yet.

He believes the technology should be widely employed just for the energy advantages:

"I just think manure is a wasted resource if it isn't converted into energy."