When you think of air pollution, you probably think of exhaust fumes from cars or pollutants produced by large factories. But animal feeding operations, such as swine (pig) farms, can contribute to air pollution, too. When dried waste, animal dander, and food residue is flushed into cesspools, it begins to decompose and is later released into the air around the farm. For kids who attend school near pig-feeding operations, these airborne pollutants can cause more frequent wheezing and exacerbate asthma symptoms, say researchers from the University of North Carolina at Chapel Hill.
Researchers surveyed 58,169 12- to 13-year-old teens about how often they wheezed, whether they'd ever had severe wheezing symptoms, and whether they'd ever been diagnosed with asthma or allergies. They also answered questions about asthma or allergy triggers at home (dogs and cats, family members who smoke, etc.). The researchers also surveyed 265 school principals about whether they could smell livestock odor outside or inside the school several days a month. Finally, the researchers determined the location of swine-feeding operations throughout the state and determined each school's proximity to them.
Overall, one quarter of the students in the study said they'd wheezed within the past year. One quarter of the schools were located within 3 miles of at least one pig-feeding operation, and at a significant number of schools, principals reported that livestock odor could at times be detected outside and inside the school.
At schools exposed to the most air pollution due to pig-feeding operations, students reported a slightly higher prevalence of wheezing during the past year. More teens who attended school near a pig feeding operation had respiratory symptoms, diagnosis of asthma, activity limitations, and missed school due to asthma or related symptoms. Among students who said they had allergies, children were 5% more likely to wheeze if they attended schools located within 3 miles of a large pig farm, and 24% more likely to wheeze if they attended a school in which livestock odor could be smelled indoors twice a month.
What This Means to You. Other studies in adults have shown that living near swine-feeding operations can cause more frequent respiratory symptoms. Kids spend several hours a day at school, and this study found that exposure to airborne pollutants from pig farms near school can exacerbate asthma symptoms. If your child complains of wheezing or other respiratory symptoms such as chest tightness, talk to your child's doctor, who may recommend medication and other strategies to help control physical symptoms.
Source: Maria C. Mirabelli, PhD; Steve Wing, PhD; Stephen W. Marshall, PhD; Timothy C. Wilcosky, PhD; Pediatrics, July 2006.
Reviewed by: Steven Dowshen, MD
Date reviewed: August 2006