Several recent dairy articles have discussed lower air quality emission numbers based on California research. Because of the current events surrounding EPA's air quality consent agreement (AQCA), people assume we're comparing apples to apples or, more precisely, dairy ammonia emission to dairy ammonia emission. Actually, California's emission's data is very different from that proposed for the AQCA.
The increased impact of animal facilities on atmospheric conditions has been on the radar screens of local and state regulatory agencies in California for some time. Because of citizen lawsuits, it became necessary for that state to develop implementation plans in several of their air management districts. The emissions of concern are volatile organic compounds (VOC) and particulate matter (PM).
VOCs are precursors to ozone formation, and much of California is in violation of threshold levels. VOC thresholds for dairies, based on 1938 research, estimates that cows produce 12.8 pounds of VOCs annually. A 700-cow dairy would equate to 4.5 tons per year of VOCs -- equivalent to 60,000 cars.
But a recent study by Frank Mitloehner, an air-quality specialist at University of California-Davis, found that dairy VOCs may be far lower â€“ as much as 50% lower.
And it suggests the cow may emit more VOCs than her excreta. This kind of research will be critical in developing regulations grounded in good scientific data, and helps in developing best mitigation practices.
What Easterners can learn from it
Currently, animal agriculture in Pennsylvania isn't regulated for air quality. Other than odor, air emissions are barely on agriculture's radar screen. But Pennsylvania and other parts of the Northeast, like California, have non-attainment areas for ammonium particulates that are in the hot bed of animal agriculture.
Over the next several years, the Northeast will have to develop plans to clean up the air in non-attainment areas. It's unrealistic to think that animal agriculture won't be expected to share in efforts to improve air quality by controlling ammonia emissions. The bottom line: Air quality concerns aren't going to go away.
Ishler is a dairy scientist with Pennsylvania Dairy Alliance. Graves is a Penn State ag engineer specializing in dairy.