Agricultural odors are a local problem, Wheeler explains, but gas emissions are a multistate and global problem. For example, she notes, scientists estimate that the majority of the ammonia in the Earth’s atmosphere comes from animal agriculture. “There are two strategies to reduce agricultural gas emissions: reduce generation at the source and reduce the release from the farm site,” she says. “Effective odor and gas-emission reduction at livestock facilities usually involves more than one practice, with feed-nutrition management on the front end and manure-emissions management on the back end.”

Although most people don’t realize it, agricultural emissions are not an insignificant phenomenon, Wheeler points out. “I recall being told by Carnegie Mellon scientists who were involved in air-quality monitoring that they could tell when the prevailing winds shifted and air was coming from the Midwest,” she says. “They said they knew because the ammonia levels in the air would rise, and they believed that was from animal agriculture in places such as Iowa and Nebraska.”

Wheeler is involved in at least a small way in nearly every agricultural-emissions research project done in the college because she is the air-quality, environmental-control specialist in the Department of Agricultural and Biological Engineering. “ As engineers, we get involved in a lot of projects to design processes for odor quantification and measurement,” she says.

Wheeler believes many small- to medium-sized Pennsylvania farms will be affected by EPA’s new enforcement of Clean Air Act regulations relating to animal agriculture emissions. “Some agricultural producers seem to believe that only big farms are being impacted by this, but smaller farms are not going to fly under the radar either,” she says. “This enforcement is going to affect most every Pennsylvania farm in some way. The new regulations are such that a poultry farm with one broiler house and perhaps 30,000 birds will exceed the ammonia limits near the end of the production flock cycle when the birds get big. The scope of the operation is fairly low to trigger the limits.”

Enforcement of agricultural emissions limits is not all-encompassing. Emissions from beef cattle operations are exempt, as are emissions from manure spread as fertilizer on fields. Emissions from manure stored in lagoons, however, will be monitored, according to Wheeler, who believes EPA officials are learning that there are challenges to enforcing regulations on agricultural emissions.

Because the initiative to regulate agricultural emissions is new and rules will evolve, experts such as Wheeler aren’t yet certain what will constitute compliance and sanctions. “I have had a hard time getting a read on what EPA is really going to do about this,” she says. “I thought initially that if you exceed limits, something was going to happen to you—a fine or other punishment. But now it seems that if a producer emits more gases than he or she is allowed to, the producer will have to report and fill out some paperwork. It appears that the teeth to force compliance with the regulations are some years away.”

Efforts to clean up the environment always cost something, Wheeler noted. “It is often worth it, but somebody always has to pay for it,” she says. “Some of these big companies with livestock already have offshore production. If compliance with agricultural emissions regulations becomes too expensive or unwieldy, they will just move the rest of their production offshore and this country will suffer economically. There is a lot at stake here.”