Cow poop isn't the villain after all

Tuesday, June 8, 2010

Fresno California has air quality problems and the huge number of cows in the San Joaquin Valley has been taking the blame. Turns out that ozone may not be coming from the cows after all, but from their feed.

There are 15 million cows in the valley, the largest dairy producing area in the United States, which is under a federal mandate to reduce its ozone levels. Farmers had installed methane digesters to treat manure, to no avail. Ozone levels kept rising, even though there isn't nearly as much auto traffic as in urban areas and efforts were being made to reduce it.

According to Associated Press, a four-year study conducted by scientists at the University of California, Davis, found that millions of tonnes of silage stored under black plastic emit ozone during fermentation. Researchers used a portable smog chamber on farms to test emissions. The study was published in April in the American Chemical Society's Journal of Environmental Science and Technology. More studies will be required to ensure that the correct conclusions have been reached.

The executive director of the San Joaquin Valley Air Pollution Control District isn't waiting for those results, however. Sayed Sadredin plans to ask his board as early as June to amend regulations and require farmers to bag their silage, a solution that will be costly but can reduce emissions by 90 per cent. Farmers will be footing that bill as well. BF