Feds at Work: Offering a cost-effective way to identify public health threats
Led the first-ever study using tree moss to detect air pollution, including cancer-causing heavy metals
When environmental officials in Portland, Oregon, found toxic heavy metals in the air several years ago, they realized something was amiss. But they couldn’t figure out where the pollution originated.
Enter Sarah Jovan, a research ecologist, and Geoffrey Donovan, a research forester. A discussion between the two U.S. Forest Service employees, on how moss can detect air quality problems in forests, led to applying the novel concept in a city for the first time.

Their collaboration, beginning in 2013, led to startling results. Donovan and Jovan used moss from tree trunks and branches as a test bed at 346 sites throughout Portland, allowing them to produce maps showing heavy metals at a level of detail never seen. The tests revealed numerous hot spots in residential neighborhoods near two stained glass manufacturers that had high and potentially dangerous levels of cadmium and arsenic. Both can cause cancer.
“It was groundbreaking work,” said Sarah Armitage, senior air quality planner at Oregon’s Department of Environmental Quality. “I don’t know if we would have figured out the source of our heavy metals without them. It might have taken us years longer.”
The June 2016 disclosures led to follow-up air quality testing by Oregon’s environmental department that found cadmium 49 times and arsenic 155 times above acceptable health levels. These heavy metals are used in stained glass, but a loophole in state and federal regulations had allowed the emissions to go unchecked.
“What I think is most significant is that it made a real difference in people’s lives.” ~ Sarah Jovan
The revelation led to tighter monitoring and regulation of glass manufacturers in Portland and the state. Factories installed new filters, and the two companies emitting the air pollution stopped working with cadmium. The moss study was a “tipping point” that led to more state funding to conduct extensive air quality monitoring, Armitage said.
And in response to the moss program’s data, the federal Environmental Protection Agency reviewed glass manufacturers across the country and tightened enforcement.
“The EPA said, ‘Let’s take a look at all these types of industries across the country and see if we missed anything,’ ” said Andrew Gray, research ecologist at the Forest Service’s Pacific Northwest Research Station. “There was a Portland impact, but a much bigger impact as well.”
Portland’s experience led to interest by Cincinnati, Seattle and other cities in using this effective and low-cost technique to monitor air quality. On average, air quality instruments each cost $50,000 annually to operate. That translates into $17 million a year for monitoring devices with the same reach as Portland’s moss sampling grid. The Portland study cost just $100,000.
Following the testing by Jovan and Donovan, and later by the state, warnings were issued in Portland against eating food from local gardens, and health screenings were made available for local residents.
“It made a real difference in people’s lives,” Jovan said.
Jovan and Donovan’s team also trained state regulators to do moss testing to pinpoint emissions problems before deciding where to deploy expensive air monitors.
“We had a modest amount of funding and luckily the freedom to follow our noses.” ~ Geoffrey Donovan
The firestorm of political and public interest in the results became a complication for Jovan and Donovan, who needed to finish their research. They were bombarded with press calls and spent hours in public meetings explaining their findings.
“Sarah and Geoffrey were really under the microscope and attending really contentious public meetings, trying to explain what they found to all sorts of regulators and politicians,” Gray said.
Donovan said the moss study shows the value of good government science.
“We had a modest amount of funding and luckily the freedom to follow our noses,” he said. “This is an example of the good things that can happen if you have that unique environment.”
Sarah Jovan and Geoffrey Donovan are finalists for a 2017 Samuel J. Heyman Service to America Medal, or Sammies. Each year, the Partnership for Public Service honors federal employees whose remarkable accomplishments make our government and our nation stronger.
For the third year, we will also present the annual “People’s Choice” award. Please vote for the person or team you find most inspiring. (Voting closes at 11:59 p.m. EST on September 15, 2017.)
