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In South Seattle, teens collect moss to help ID air quality

Duwamish River Cleanup Coalition
Two members of the DRCC’s Duwamish Valley Youth Corps, which helped collect samples for The Moss Study in South Seattle.";

Residents of Seattle’s Duwamish River Valley have long known they suffer from high levels of air pollution. Air pollution that comes from nearby heavy industry, highways and air traffic has plagued South Seattle neighborhoods.

To the point that we have 13 years of life expectancy difference between South Park and Magnolia, for example,” said Paulina Lopez, executive director of the Duwamish River Cleanup Coalition.

Now the coalition has collaborated with the U.S. Forest Service and several other partners to collect moss samples from a grid covering South Park and Georgetown. The Moss Studysamples were analyzed for 25 heavy metals and other elements. The data will be used to decide where regulators should place high-tech sensors to follow up on hot spots. 

Those collecting the moss samples? Twenty-six teens from the Duwamish Valley Youth Corps. Project organizers say one of the most important aspects of the project is how it trained and empowered local youth to be citizen scientists.

“Everybody recognizes the poor air quality in the lower Duwamish and kids are especially impacted by that,” said Dale Blahna, a research social scientist with the Forest Service. “The younger you are when you get exposed to pollutants, the more likely it is to have negative impacts on the body. And asthma rates are real high in the Duwamish Valley and all the kids know that. So, being able to get local youth involved was really kind of a double benefit.” 

The youth collected 80 moss samples. Professional scientists collected an additional 20 samples to help verify the results. They were analyzed for heavy metals and other elements. Data collected has shown high levels of arsenic and chromium; results were twice as high as what was found in Portland, where a similar study had been previously done.

The information from the study will be even more critical as the valley navigates the impacts of the West Seattle Bridge closure and likely lots of detour traffic near their neighborhoods.

Bellamy Pailthorp covers the environment for KNKX with an emphasis on climate justice, human health and food sovereignty. She enjoys reporting about how we will power our future while maintaining healthy cultures and livable cities. Story tips can be sent to