Farming-related air pollution linked to deaths, study says
MARIETTA — Luke Brubaker admitted that he’s proud of his soil as he bent over and gestured with an extended arm to a field on his northwestern Lancaster County dairy operation.
He pointed to the largely unbroken soil, where modern farming practices allow feed to be planted without tilling. And he noted tiny slits in the dirt, where fertilizer was injected directly into the ground instead of slathered on top.
“See, it’s not all torn up,” he said, highlighting the effect of farming practices that lock soil and nutrients in the ground, keeping them from washing or blowing away where they can become harmful pollutants.
Those methods were among numerous conservation practices Brubaker made sure to highlight as he offered something of a rebuttal to recently published research that links farming-related air pollution to premature deaths.
That study estimated that air pollution from Lancaster County farmlands causes about 184 deaths annually, according to Jason Hill, a University of Minnesota professor. That’s about 0.075 deaths for every one of Lancaster County’s 2,440 square kilometers of land. Some of those deaths, he noted, may be recorded out of the county — a result of local pollutants carried elsewhere by weather.
Those local figures were plucked from a study published last month in the Proceedings of the National Academy of Sciences by Hill and more than a dozen fellow researchers, who set out to examine the relationship between food production and air pollution.
Nationwide, they found that agriculture-related air pollution is responsible for 17,900 yearly deaths.
“Air pollution is the top contributor to reduced human health from environmental sources,” Hill said.
It’s a statistic that’s attracted attention in Pennsylvania and, specifically Lancaster County — the most productive, non-irrigated farming county in the United States, home to more than 5,000 individual farms.
“It’s something that’s being talked about, absolutely,” said Liam Migdail, spokesman for the Pennsylvania Farm Bureau.
However, industry leaders wish more of that discussion would focus on the growing adoption of farming practices that can help capture air pollutants, Migdail said.
“These are all practices that are in place in farms in Lancaster County and they are expanding,” Migdail said, holding up Brubaker Farms LLC as an example. “The last thing that any farmer wants to do is damage their community or cause a health problem.”
Agriculture has long been identified as a contributor to air pollution. But Hill said the study he collaborated on is novel because it used modern air-quality models and county-level data from federal regulators to examine the impact of individual types of farming — concluding that animal agriculture is a leading cause of air pollution.
Mainly, the study focused on particulate pollution — microscopic solids and liquids floating in air that can be created through on-farm activities like tilling, field burning and machinery use, as well as by livestock kicking up dust.
Particles also can be created during chemical reactions in the air, including when ammonia reacts with other airborne substances to form salts, according to Richard Clark, chair of the Earth Sciences Department at Millersville University, where he teaches meteorology.
Ammonia is emitted into the air from animal waste, as well as when it is spread atop fields as fertilizer, said Clark, who was not a part of the study.
Within the published study, Lancaster County stands out in the United States, both for its high levels of ammonia emissions and total farming-related particulate pollution, Hill said, comparing it to neighboring regions.
The type of particulate pollution of concern in the study is called PM2.5. The name means individual particles are no larger than 2.5 micrometers — 30 times smaller than the width of a human hair.
Because they are so small, the particles are a threat to human health, according to Alan Peterson, a medical doctor in Lancaster County who has long studied the relationship between health and the environment.
The tiny particles are easily inhaled, bypassing bodily defense systems to enter the lungs, where they can then make their way into blood vessels, he said.
“Once they are there they can get into literally any organ in the body,” Peterson said.