While those participating get immunity for presumed air quality violations during the study, only 20 livestock barns and manure-storage facilities nationwide - none in Alabama - will be monitored.

Scientists begin work at those 20 facilities in May, and farmers hope they'll be able to use information gathered in the study.

"We need to study and look, as these farms get bigger, to see what we're doing," said Tim Donaldson, whose Calhoun County hog operation averages about 2,400 sows in 20 barns. "I'm interested in seeing what emissions we're producing out of those farms, too, to see how it compares to larger industries. If we do have an emissions problem, I want to see what we can do to reduce them."

It's not about odor; it's about materials such as ammonia, which is an ingredient in forming fine particulate matter that can cause health problems. The agreements are with large-scale farms where hundreds, even thousands of animals are confined and fed for at least 45 days a year.

Source: Al.com