The proposed siting of hog production facilities is all about location, Harmon emphasizes. The distance to nearby dwellings, the size of the pork production facility and the exposure angles — from the facility to a residence — must be taken into account.
Before siting, study the historical prevailing winds for direction and frequency during various times of the year. Understand the percentage of time (hours) that a dwelling will experience the “downwind” direction of prevailing winds. The exposure angle — the angle when neighbors are directly downwind — should be documented.
The terrain will affect the intensity of the odor. “As winds die down, wind flows down through valleys,” he explains.
“Acceptable distances are not equal in all directions,” reminds Harmon. “In Iowa, predominant summer winds are from the south and south-southeast. A facility to the south of a neighbor at a given distance has a greater odor impact than one to the north at the same distance.”
Selecting the proper site for a new hog production unit is one of the cheapest odor-control options available, he adds.