(By Suzanne Potter – Iowa News Service) =  Iowa has the highest number of hog farms and the sixth-highest number of cattle feedlots in the country, according to a new study from the University of Michigan. Researchers mapped large cattle and pig farms, finding Iowa hosts almost more than 2,100 pig animal feeding operations, known as AFOs. The state also hosts 604 cattle AFOs.

Sanaz Chamanara, now a researcher at the University of California-Santa Barbara, who led the study while at Michigan, said air pollution measures 11% worse in areas near pig AFOs and 28% higher near cattle AFOs, specifically particles measuring 2.5 micrometers. “2.5 is a concern because it lingers in the air,” Chamanara explained. “And its association with asthma, lung cancer, cardiovascular diseases and leukemia.”

The pollution comes from dust kicked up by the animals’ hooves and from massive lagoons of waste found near AFOs. Industry trade groups criticized the study, claiming it does not take pollution from transportation and human sources into account, something the authors deny. Plymouth, Kossuth, Hardin, and Franklin counties have the highest number of hog farms but the number is high because local size limits means Iowa AFOs are smaller than the national average.

A farm with more than 1,000 animals is called a concentrated animal feeding operation, or CAFO. Chamanara noted communities near CAFOs tend to have a lot in common, with many of them hosting a high percentage of vulnerable, low-income Latino residents. “The poverty is higher, the uninsured people are higher,” Chamanara reported. “But we should mention that actually the unemployment rate is lower, because these CAFOs also offer job opportunities.”

The study is the first national database of its kind and counters the argument from AFO owners no evidence links feedlots to air pollution. The authors suggested states limit the number of AFOs and encourage farmers to reduce air pollution with windbreaks and covers on waste lagoons.