Communities near Sea-Tac Airport exposed to unique mix of air pollution, UW study finds

SeaTac, Wash. — Communities underneath and downwind of jets landing at Sea-Tac Airport are exposed to a unique mix of air pollution, according to a new University of Washington study.

Researchers said the ultrafine particle pollution is distinctly associated with aircraft.

The study is said to be the first to identify the unique signature of aircraft emissions in Washington.

Sea-Tac Airport is the eighth-busiest U.S. airport. In 2018, the airport served nearly 50 million passengers and saw 438,391 takeoffs and landings, researchers said.

The findings come from the two-year Mobile ObserVations of Ultrafine Particles or "MOV-UP" study, funded by the Washington State Legislature, to examine the air quality impacts of air traffic on communities within 10 miles of SeaTac Airport.

Researchers said they collected air samples at locations around the airport over a year between 2018 and 2019.

Locations included a former elementary school south of the airport and the SeaTac Community Center north of the airport.

The samples were collected through mobile monitors that were planted on hybrid vehicles that drove on 11 routes north and south of the airport in all four seasons of the year, officials said.

A new method was developed to distinguish between pollution from jet traffic and pollution from other sources like roadway traffic, according to the researchers.

Ultrafine pollution particles are emitted from both sources, officials said.

Researchers said they found key differences in the particle size and mixture of particles they emit.

The researchers said they then mapped each type of emission mixture to show its specific geographic footprint around Sea-Tac.

"We found that communities under the flight paths near the airport are exposed to higher proportions of smaller-sized, ‘ultra-ultrafine' pollution particles and over a larger area compared to pollution particles associated with roadways," said Edmund Seto, co-principal investigator and associate professor of environmental and occupational health sciences in the UW School of Public Health.

Researchers said ultrafine particles are less than 0.1 micron in diameter, or 700 times thinner than the width of a human hair.

However, the researchers created the term "ultrafine" to refer to smaller ultrafine particles between 0.01 to 0.02 microns in diameter.

"Although this study did not consider the health effects of exposure to roadway or aircraft-related pollution, previous studies suggest smaller pollution particles are more likely to be inhaled and to penetrate the body than larger particles," officials said.

Researchers said other studies have linked the exposure of ultrafine particles to breast cancer, heart disease, prostate cancer and a variety of lung conditions.

The Washington State Department of Health is said to be preparing a literature review of the potentials health effects associated with ultrafine particles.

"We can now study the specific health effects of aircraft-related pollution, how different neighborhoods may be affected by it and specific interventions that could reduce human exposure to these pollutants," said Michael Yost, professor and chair of the Department of Environmental & Occupational Health Sciences, and co-investigator on the study. "We hope to work with state and local policymakers as well as affected communities to pursue these questions."