Researchers study air quality, heaters in livestock buildings

A current research project based in the Great Plains Center for Agricultural Health (GPCAH) is investigating methods to improve air quality in swine farrowing buildings1. The research team developed models to estimate room concentrations of multiple indoor contaminants [ammonia, dust, hydrogen sulfide, carbon monoxide, and carbon dioxide (CO2)] and conducted field monitoring to evaluate the effectiveness of using ventilation and engineering controls.

In both modeling and field work, the researchers found that CO2 concentrations exceeded recommended workplace limits for swine workers2 (1540 ppm) over the entire winter season and also exceeded one-half the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL=5000 ppm), which is based on exposure to a single contaminant (unlike what exists in swine buildings). Sources of CO2 in livestock production include both animal respiration (exhaled breath) and combustion products from heaters.

Since controlling animal breathing is infeasible, the team evaluated whether the unvented heaters commonly used throughout the Midwest (e.g., LB White heaters) were a significant contributor to high CO2 levels measured in livestock buildings. In fall 2014, researchers installed new gas-fired heaters, the Effinity93 (60K BTU, approximately $500 more than equivalent LB White unit), in a test barn. The team measured concentrations throughout the following winter, comparing them to that of the previous winter with traditional unvented heaters.

To protect the unit from dust, fresh air intake to the combustion device was from outside the farrowing building, and combustion gases were exhausted from the unit to outside the building. The investigators identified that CO2 was reduced by 800 ppm with the new heaters.

Another 200 ppm difference in CO2 between seasons was attributed to colder outdoor temperature and larger in-room animal population in the winter with the older unvented heaters. Other vented gas-fired heaters are available, and the researchers recommend substituting unvented heaters with vented units that have stainless steel internal components, which should improve the lifespan of the heater when used in livestock environments containing ammonia.

1. See for more details on this larger project.
2. Donham K, Haglind P, Peterson Y, et al. (1989) Environmental and health studies of farm workers in Swedish swine confinement buildings. Brit. J. Industr. Med. 46:31–37.

This story originally appeared in the September 2015 issue of Farm Families Alive & Well

New study looks at types and causes of tractor-related injuries

A tractor on display outside of the College of Public Health.Although farming is a rewarding career critical for Iowa and the nation, it can be dangerous work. Estimates suggest that 2 of every 20 farmworkers are likely to be injured in the United States each year.

Tractors are a particularly dangerous source of injury. While national databases keep track of tractor-related fatalities, the number of people sustaining severe injuries and how these injuries occur is less clear. What is known is that nonfatal tractor-related injuries are common and preventable, with some suggesting the rate is 30 times that of fatal tractor injuries.

Types and causes of tractor injuries

In an innovative, first-of-its-kind study, University of Iowa researchers led by Amanda Swanton, a doctoral student and researcher with the Injury Prevention Research Center (IPRC), and Corinne Peek-Asa, professor of occupational and environmental health and director of the IPRC, analyzed 513 cases of nonfatal injury from the Iowa Trauma Registry, the database of the Iowa Trauma System, to examine the types and causes of tractor injuries that required emergency care. The cases were from 2002–2012. The study was published in the Journal of Safety Research.

Study results showed that tractor rollovers were the primary cause of the most severe injuries. As recent technical innovations have focused on reducing the number of tractor rollover deaths, it may be that fewer fatalities have meant a higher number of severe injuries. Other frequent causes included jumping/falling/being thrown from the tractor, being run over, and collisions, often with non-farm vehicles on roads.

Bone fractures were by far the most common type of injury (almost 50%). Other common injuries included internal or open wounds. While most of the injuries were not that severe, the average hospital stay was 3 days, and could range up to 68 days. Notably, 23% of patients required at least one day in the intensive care unit.

Age and injuries

Age affected type and severity of injury. Children were most likely to be hurt falling or jumping from a tractor, young adults by rollover or collision. Those ages 25-44 were most frequently involved in collisions, suggesting that this age group is responsible for transporting farm goods on roadways. Farmworkers in their 40s were injured often but not severely, while those over 55 had a lower risk of injury but a higher risk of being badly hurt, perhaps due to being less resilient and more fragile.

According to Swanton, “the tractor is an everyday part of farm life, and it can be hard to imagine that such a trusted piece of machinery can be dangerous. Tractor injuries are usually sudden and unexpected, but they are also preventable. Making sure tractors have rollover protective structures, are kept in good working condition, and using common sense when working with tractors can go a long way in preventing injuries.” Swanton is a student in the UI Medical Scientist Training Program that provides training for both the MD and PhD degrees.

Studies like this are critical to the effort to reduce the number of farm injuries. Possible approaches might include reconsidering tractor design, how farm equipment interacts with roadways, and how best to educate farmworkers on tractor safety.

The research team also included Tracy Young, injury epidemiologist with the IPRC; Kathy Leinenkugel, Iowa Department of Public Health; and James Torner, a faculty member with the IPRC and professor and head of epidemiology in the UI College of Public Health. The study was funded by the UI Great Plains Center for Agricultural Health.