A study by an Iowa State University researcher finds that inside sources — not nearby hog confinement operations — may be responsible for causing problems for homeowners. Researcher Steven Hoff measured the levels of hydrogen sulfide and ammonia taken outside and inside homes located near the hog confinement operations.
He says they found inside-the-home ammonia levels were consistently higher than outside levels and “it was not related to whether or not this home was upwind or downwind of any animal source in the area.” Hoff conducted the study over a 16-month period around hog confinements ranging from 1200 to 4800 hogs. He says they’re seeing a “disjunction” between the inside ammonia levels and what’s going on outside the home.
Hoff, who works in the ISU Department of Agricultural and Biosystems Engineering, says they suspect there are some “inside sources” causing the elevated ammonia levels in the homes. Hoff says one of the ammonia sources could be attributed to a litter box. Hoff says in one, there was smoking inside the home, and in another, they kept pets inside the home. Hoff says they’re still looking for sources inside the home that could contribute to the ammonia levels, and they’ve put together a test lab at Iowa State to look at the inside sources.
The Iowa Department of Natural Resources recently released a study of air quality around hog confinements. Hoff says his study confirms some of the DNR findings. Hoff says the DNR did not have any measurements that exceeded the “health effects value” level set for hydrogen sulfide — which he says is very similar to what he’s found in his work. Hoff says they looked at some smaller hog confinements, but his findings “are very much in line with what the DNR is finding.” Hoff says his study doesn’t mirror the DNR study and is different because he looked simultaneously at the inside air levels as he measured the outside levels. Hoff says he wanted to “know that if we measure something outside of our home, does that automatically mean that it will be a measurable quantity inside the home as well? So, I wanted to see that link.”
Hoff’s study was funded, in part, by the National Pork Board.