Dairy Cows Pass Gas, but How Much?

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Dairy cows either: a) pollute the air a lot less than previously thought, b) a lot more than previously thought, or c) about the same as was thought. The answer is all of the above, according to a committee charged with figuring out what the San Joaquin Valley's dairy cows contribute to smog.

Dairy cows either: a) pollute the air a lot less than previously thought, b) a lot more than previously thought, or c) about the same as was thought.


The answer is all of the above, according to a committee charged with figuring out what the San Joaquin Valley's dairy cows contribute to smog.


Though members of the committee failed to reach a consensus in Friday's report, the ultimate decision has multimillion-dollar implications for the dairy industry -- which produces the region's No. 1 agricultural commodity.


Milk generates $1.24 billion in farm revenues in Stanislaus, Merced and San Joaquin counties.


At issue are the volatile organic compounds -- which are smog-inducing chemicals -- created by dairies.


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The committee, an advisory group to the San Joaquin Valley Air Pollution Control District, is called the Dairy Permitting Advisory Group. It is made up of dairy industry representatives, environmentalists, community groups and air district officials.


Friday's report is a preliminary step in setting up a permit process for dairies, which were previously exempt from air pollution permits. Once the new system is in place and the pollution level is determined, the air district can decide what mitigation measures dairies will have to take to minimize pollution.


The committee's report lists three possibilities and leaves the final determination to David Crow, the air district's air pollution control officer. He has until Aug. 1 to decide which option to endorse.


The decision could have big ramifications for the dairy industry, according to Michael Marsh, chief executive officer of Modesto-based Western United Dairymen.


There are more than 2 million dairy cows in the San Joaquin Valley.


Particles in the waste they generate, in addition to the gas they expel, become part of the valley's air -- among the worst in the nation.


Quantifying cows' effect on the air, by measuring the gas, is where the reports' authors disagree.


If the lowest of the three figures (5.6 pounds per year per cow) is endorsed by the air board, Marsh said, dairies might only have to change some management controls, such as cows' diet, the frequency of flushing waste material out of the buildings or further separation of solids in the waste.


But if the highest figure (38.2 pounds per cow per year) is chosen, dairies could be forced to spend millions of dollars on technology such as methane digesters, according to Marsh.


The middle figure (13.3 pounds) is close to the disputed number (12.8 pounds) that has been used since a 1938 study.


Even the middle number makes dairies the No. 1 source of volatile organic compounds in the valley, ahead of trucks and cars.


"I think the three different perspectives are three equally valid ways of looking at the available data," said committee member Dave Warner, director of permits for the air district. "It's no surprise to me that a given set of data can be interpreted a number of ways."


The committee looked at four California studies, as well as other studies and factors that might contribute to dairy emissions:


--The lowest number is based on the California studies and is favored by the dairy industry.


--The middle number adds factors that the air district staff felt were missed in the California studies.


--The highest number, favored by environmentalists, includes data that was acquired from studies outside the state.


Marsh said in a statement that he was "disappointed and concerned that politics appears to have entered into what was supposed to be a science-based process."


Public workshops are coming Marsh said the highest number is "way out there, not related at all to scientific data." Data from studies done in other countries under different circumstances were used, he said.


But committee member Diane Bailey of the Natural Resources Defense Council said the California studies didn't cover some pollutants related to volatile organic compounds.


"It's not the fault of the researchers, but there are some huge blanks and we attempted to fill them up," she said.


That was accomplished by using data from studies done outside of California and translating the results to the situation here, Bailey said. "I feel it is based on the best available science."


Bailey added that there is a cost to choosing a number too low.


"The residents of the valley are subsidizing the (dairy) industry with their health," she said. "There is a health care dollar cost."


Warner said public workshops will be held before Crow makes his recommendation Aug. 1.


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Source: Knight Ridder/Tribune Business News