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Friday, August 12, 2005
Pena: Cows are big air polluters?
By Rox Pena
I NEED to pass a vehicle emission test before I can register my car. I need a permit before I can construct and operate an air pollution source like a boiler or generator. But, do I need to get a permit to raise cows? It may sound ridiculous, but in some countries, it's true. This is one issue that I have been closely watching. It's something that I never thought would be possible.
In Sacramento, California, a report was released last week saying that dairies - milk producing cow farms - are the No. 1 source of smog-producing pollution in San Joaquin Valley. They produce more than cars and light trucks. Smog is the fog-like cloud cover that we see in polluted areas. The main component of smog is ground level ozone, which is caused by the reaction of pollutants like nitrous oxides and volatile organic compounds (VOCs) with sunlight. The San Joaquin Valley Air Pollution Control District says a cow creates about 8.8 kilograms of VOCs annually. Other animals can also contribute to VOCs but cows are the number one targets because of their size.
The targets of regulation, although are big farms and not the small scale, backyard operations. Under California laws, agricultural operations, which emit 11,364 kilograms of VOCs per year, are required to obtain a permit. Farms with about 1,300 heads will emit that much VOCs using the given emission standard of 8.8 kilos per cow. Agricultural operations used to enjoy exemptions from emission limits, until an amendment to the California Health and Safety Code implemented on January 01, 2004 scrapped the exemption.
The source of pollution is the cow's eating process. After a cow eats, the food is briefly deposited in its big stomach. It mixes with bacteria where it breaks down and produces methane. After about 20 minutes, the food comes up again as cud. When the cow chews it, it releases VOCs like methanol and ethanol, along with another deadly gas-methane.
Methane, a greenhouse gas that is 21 times more deadly than carbon dioxide, is another concern. Some studies suggest that a single cow produces about 600 liters of methane per day, enough to inflate 40 party balloons. It is said that 20% of methane gas released into the atmosphere comes from cows.
Concerns on cow pollution are not confined in the US. Livestock are also responsible for more than half of Australia's methane emissions. According to state authorities, up to 90% of methane produced on Victorian farms comes from burping and breathing of cattle. In another country, environmental scientist professor Frank Convery claims cows breaking wind and belching account for 35% of Ireland's greenhouse gas emissions. Gas emissions from flatulent cows could soon be restricted by the European Union's quota system.
So, how do you reduce cows' harmful emission? For man-made equipment, it's easy. A car or a boiler can be fitted with pollution control devices, or can be fed with clean fuel. With a polluter that is alive and breathing, interventions must be as natural and cost-effective as possible.
A new study in Canada found about 20 different ways to reduce methane and nitrous oxide emissions from livestock. Each of these has the potential of cutting down emission by one-third. North America has more than 100 million cattle, hundreds of millions of hogs and feeder pigs, and more than two billion chickens. Together, they emit billions of tons of carbon dioxide equivalent to greenhouse gases every year.
Some of these steps are providing high quality grass pastures; rotational grazing, grinding and pelleting feeds; adding a small percentage of canola oil to cattle feedlot rations; keeping young pigs and poultry separated by age groups; and phasing their feeds by growth stages.
Now read this: We breathe in oxygen and breathe out carbon dioxide, the main global warming gas. Luckily, plants do the opposite - taking in carbon dioxide and releasing life-sustaining oxygen. But if we cut trees faster than we replace them, will human population be the next target of regulation?
(August 12, 2005 issue)
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