Ammonia study fuels concerns over dairy emissions

A recent survey showing “slight improvement” in air pollution releases from Yakima County dairies isn’t easing the concerns of neighbors and environmentalists, especially with a new study linking ammonia from manure to decreased lung function in children with asthma.

The survey comes two years after officials set a mandatory air quality policy for county dairies.

In 2014, survey officials gave 12 percent of the dairies a D score on a program of management practices designed to reduce air pollution from manure and dust. Follow-up inspections in 2015 showed those facilities had taken small steps to improve, said Hasan Tahat, engineering supervisor for the Yakima Regional Clean Air Agency.

Facilities that scored above a D in 2014 weren’t re-inspected in 2015. But Tahat said he’d heard anecdotally that some of the already higher-ranked dairies had continued to invest in state-of-the-art pollution controls such as enclosed feeding areas and systems to separate solid manure from wastewater.

The study of children with asthma was conducted by scientists from the University of Washington in collaboration with the Yakima Valley Farm Workers Clinic. It monitored 51 children for several months with daily lung tests and correlated that data with nearby ammonia monitors.

Higher ammonia levels were associated with a 4 percent decrease in lung function, said Catherine Karr, the UW pediatrician who lead the study. That may not sound like a significant impact, but Karr said it’s in line with the impact of other well-studied asthma triggers, such as mold and cockroaches.

“Ammonia is an irritant, and we expect that it could have an immediate effect and that’s what we saw,” she said.

“We looked at ammonia because we thought it would be a good marker for animal operations. The major source of ammonia is from manure and the breakdown of waste,” Karr said.

But she added that emissions from dairy farms are just one of the asthma triggers affecting those who live in a rural environment.

Conflicting claims

Jennie Larez knows that all too well. The 61-year-old Harrah resident said the combination of her severe asthma and activities on neighboring farms keeps her largely home-bound.

“The dairy pollutes the air so bad when they are spraying the poop through the sprinklers that I can’t even go outside without a respirator,” she said. “But it’s also bad when others spray pesticides or when they harvest the wheat, even when people are burning the ditches, so everything gets me.”

Her doctor tells her to move, she said, and they plan to when her husband retires in a few years.

Jean Mendoza, an environmental advocate with the group Friends of Toppenish Creek, said stories like Larez’s make it frustrating that clean air officials have seemed to shrug off the asthma study’s findings.

She’s concerned with statements that Clean Air Director Gary Pruitt gave to the Washington Dairy Products Commission for an article the commission wrote that was published without a byline in the Yakima Valley Business Times and the Toppenish Review in January.

“We had no issues whatsoever with 85 to 90 percent of the Valley dairy operations where we scheduled site visits, reviewed the (best-management practices) checklist and discussed how best to proceed at each farm,” Pruitt was quoted in the article.

But data from the 2014 site visits at 59 Valley facilities shows the agency found significant issues at 49 percent of them, earning them a score of C or D.

The Washington Dairy Products Commission article also said experts have found no evidence that dairy farm emissions are a health risk.

Studies have raised questions. A recent national study found dairy workers were not exposed to any air pollution levels high enough to violate occupational health standards. On the other hand, a state study found ammonia emissions were a significant contributor, after wood smoke, to elevated levels of winter air pollution in the Yakima Valley.

“I think Clean Air needs to issue a clarification of that newspaper article because other studies show how ammonia is a risk to public health,” Mendoza said.

No measurements

Much of the confusion and debate about dairy emissions stems from the fact that they are difficult to measure, unlike an industrial facility with a smokestack.

“Unless you enclosed the whole dairy, all 30 or 40 acres, in a giant dome with a pipe, there is no way, scientifically speaking, to measure dairy emissions before and after a control,” Tahat said. “We aren’t putting a number on emissions because we can’t. Each dairy is different.”

That’s why the Clean Air Agency adopted its dairy air plan, which was based on several levels of best-management practices that have been shown to reduce emissions. It’s far more practical to implement, but there’s no way to measure exactly how much each dairy that adopts a certain strategy has reduced its emissions.

“Every improvement is an emission reduction. For example, if they were scraping (manure from) pens once a week and now they do it twice, that’s an improvement, and they go from a 3 to a 4 on a scale of 5,” Tahat said.

Another area of improvement most dairies have adopted is the use of nutrition consultants to make sure the cows’ feed doesn’t include too much protein. If cows can’t digest extra protein, it causes increased emissions from their manure, Tahat said.

The new program has yet to take any regulatory action against any dairy for not complying with the best-management practice policy. But Tahat said the agency can do so for any facilities that decline to do basic-level management.

“Prior to the policy, we couldn’t issue tickets, but now if people aren’t going to comply, we have that authority,” he said. “It’s going to take time, but we are seeing improvements.”

This story was originally published March 2, 2016 at 4:42 PM with the headline "Ammonia study fuels concerns over dairy emissions."