Does air coming from hog confinements contain manure?

The air leaving Iowa hog confinements contains manure and should be illegal under state law, according to a petition filed with the state.  Four northeast Iowa residents want the Iowa Department of Natural Resources to regulate the release of manure through the air in the same way it regulates the release of liquid manure.  The state requires that manure be retained until it's applied as fertilizer to farm fields, the petition says.  "We contend the 24/7/365 discharge through air vents or blowers contain excreta/waste/manure," according to the petition filed by Bob Watson and Dick Janson, both of Decorah, Larry Stone of Elkader, and Lew Klimesh of Waucoma.  The petition argues that farmers are not containing all their manure in between fertilizer applications, said Dan Andersen, an Iowa State University agricultural and biosystems engineering assistant professor.