What's in Georgetown's Air?

Study measures particulate matter PM 2.5 that can cause health problems

Preliminary data from air monitors at four locations in Georgetown measured fine particulate matter for the past year. On average, readings rose in the afternoon. The research is part of a study between University of Washington researchers and the Duwamish River Community Coalition. (Chart created by UW's DEOHS with data from Clarity monitors)

A local study is measuring levels of fine particulate matter, some of the most dangerous things we breathe each day in Georgetown.   

At 2.5 micrometers (PM2.5) or less, the size of these small particles is only a tiny fraction of a human hair. So, they can easily get into our lungs and bloodstream raising the risk for heart and respiratory issues and some cancers, especially for children and those over 65. 

Sources of fine particle pollution include wildfires, vehicle exhaust, wood-burning stoves and industrial activities with combustion. Given Georgetown’s location next to Interstate 5, train tracks, King County International Airport-Boeing Field and all sorts of industry, it’s no surprise Georgetown has air pollution. And with the Puget Sound Clean Air Agency approving Ash Grove Cement’s request to burn more tires each day, the air isn’t going to get any cleaner.   

But just how much air pollution is here and where are the neighborhood hotspots?

University of Washington researchers and advocates at the Duwamish River Community Coalition are trying to answer those questions. 

Over the past year, low-cost air monitors have taken levels of fine particulate matter at sites including a spot near Seattle Iron & Metals on East Marginal Way, the Mini Mart, Oxbow Park and the Georgetown Playfield. There are also several monitors in South Park. The air monitors do not measure ultrafine particulate matter, smaller than .1, which is associated with airplane exhaust.

The U.S. Environmental Protection Agency says the concentration of PM2.5 should not exceed a daily average of 35 micrograms per cubic meter (µg/m³) while the World Health Organization recommends not exceeding 15 µg/m³.  

According to preliminary data, the monitor readings never exceeded the EPA standard and averaged around 6 and 7µg/m³ over the past year. The levels did exceed the WHO standard on some days. Readings also tended to peak between 2 p.m. and 10 p.m., especially near Seattle Iron & Metals getting up to 8.5 µg/m³. The readings were higher in high-traffic areas possibly due to more idling cars and port-bound drayage trucks, said Joseph Santana, environmental health equity manager at the Duwamish River Community Coalition. 

Compared to some places in the world, the measurements are not alarming, but they are certainly higher than nearby Beacon Hill, many other Seattle neighborhoods or other Washington communities like North Bend, Santana said.

The data is gathered using low-cost monitors that are not approved for federal monitoring. Although they do not meet federal standards, the data is in line with readings from other officially approved devices meeting federal equivalent methods, Santana said. This suggests the monitors are still producing relevant, useful data, Santana said. 

University of Washington researchers and Duwamish River Community Coalition advocates are partnering on the study, which is part of the larger Duwamish Air Improvement Study for Youth (DAISY) project to reduce childhood asthma symptoms in the Duwamish Valley. The project is supported by a National Institute for Environmental Health Sciences grant. A separate DRCC study found indicators of metal pollution in the moss on neighborhood trees.

The air monitors are supposed to gather more data through 2027, but as with much federally supported scientific research under the Trump administration, future funding is in question, Santana said. 

The DRCC continues to recruit children ages 6-17 with asthma for the study and is offering a $250 stipend. For more information, go to drcc.org/daisy or email contact@drcc.org.