Pollutants differ on the farm, but still play role in asthma

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Pollutants differ on the farm, but still play role in asthma

Researcher studies air quality sources, effects in Yakima County
Elizabeth Sharpe

Air pollution tends to be thought of as an urban problem, not an issue in agricultural areas such as those in Eastern Washington. Scant research exists about the health effects of air pollution on communities around industrial-scale farming operations.

Catherine Karr, an associate professor of pediatrics and environmental and occupational health sciences at the University of Washington, is investigating air pollution in the Yakima Valley and how it may affect children who suffer from asthma.  

Catherine Karr is investigating the causes and effects of air pollution in Yakima County, Wash.
picture of Catherine Karr

This chronic disease affects nearly 106,000 kids in Washington, with close to 5,000 of them in Yakima County, according to estimates by the American Lung Association. Asthma causes inflammation and narrowing of bronchial tubes, which limits the amount of oxygen delivered to the lungs. Wheezing, coughing, tiredness, and shortness of breath are a few symptoms, and without treatment, an asthma attack can lead to an emergency room visit or hospitalization. 

Karr and colleagues gathered daily data on the volume of fine particulate matter from a monitoring station operated by the Yakima Regional Clean Air Agency, but they also needed to learn exactly what was in the air. Studies on urban air pollution point to traffic emissions as a primary component, but sources might differ in rural areas, the researchers speculated.

Yakima and Toppenish are small towns with big industry. Tree fruit. Dairy. Beef. Wheat. The production of each is associated with air pollution: Farmers protect apple orchards with pesticides. Tractors harvesting wheat churn up clouds of dirt and grain. Trucks carrying corn and beans run on diesel and keep dust swirling on roads. Animals' waste emits ammonia.  

Michael Yost, professor and chair of UW's Department of Environmental & Occupational Health Sciences, and others designed an air-monitoring device that isolated contaminants in the air. Every six days, the device ran round the clock and collected samples to measure pollen, pesticides, dust, endotoxin (an immune-system reacting component of bacteria) and ammonia.

Fourteen devices were placed at homes of kids in the community and used to create a map of pollutant levels for all 58 children enrolled in the study. Nearly all of the children in the study were Hispanic, with median household income below $30,000. 

Asthma is a chronic, life-limiting disease that affects about 106,000 kids in Washington -- close to 5,000 in Yakima County, according to the American Lung Association. Asthma inflames and narrows bronchial tubes, limiting oxygen intake.
picture of boy using inhaler

For two years, health data on their lung function was measured daily with a special instrument, and control of asthma symptoms was assessed every two weeks in a phone survey. Health providers also tested the kids’ lung function once a year. 

Initial findings show evidence of more asthma symptoms and worse lung function following higher air pollution days, Karr said. Only 26% of the children had consistently “well-controlled” asthma, based on symptom and medication use -- but over the course of the study, all of the children improved.

“I think this reflects that kids and their caregivers in this study had a community health worker paying close attention to the child’s asthma status and received helpful education on managing their disease,” Karr said. Most people, however, "don’t have control over air pollution outside in their community or even in their yards. This study can help facilitate more attention to the problems and motivate solutions.”

While she is in the process of publishing these findings, she is already evaluating the effectiveness of high-efficiency particulate air (HEPA) purifiers in the homes of these children. She recently received a $2.5 million grant from the National Institute of Environmental Health Sciences for that study.

These studies are part of the El Proyecto Bienestar (The Well-Being Project), funded by the National Institutes of Health, which connects Hispanic agricultural workers and local organizations with researchers to address the occupational and environmental health risks facing the workers and their families.

Others involved include researchers in the Pacific Northwest Agricultural Safety and Health Center, Heritage University, Yakima Valley Farm Workers Clinic, and the Northwest Community Action Center, which includes Radio KDNA.