Des Moines Air Quality Monitoring Station (AQMS)

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The Des Moines Air Quality Monitoring Station (AQMS) will provide long-term, community-centered measurements of ultrafine particles and other air pollutants south of Sea-Tac Airport. Building on UW’s Mobile ObserVations of Ultrafine Particles (MOV-UP) study, the station will help distinguish local aircraft-related pollution from broader regional sources.

The station at a glance

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< 100 nm

Ultrafine particle diameter.

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10–20 nm

Particle range indicative of aircraft emissions.

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5

UFP, PM2.5, black carbon, NO₂ and CO.

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2

Monitoring sites at opposite ends of Sea-Tac Airport.

Ultrafine particles and health

Ultrafine particles are smaller than 100 nanometers and may affect health. Aircraft emissions carry a distinct particle-size signature, so measuring particle size helps separate aircraft pollution from other sources.

Diagram comparing particle sizes: ultrafine particles (under 100 nm) are far smaller than fine (PM2.5) and coarse (PM10) particles.

Instruments

Measured pollutants and instruments

The Des Moines AQMS continuously measures key air pollutants from transportation and other combustion sources. Together, these measurements help track local air quality and how it changes with weather and airport operations.

Instrument used to measure ultrafine particle concentrations and particle-size distributions.A

Ultrafine particles

Particle count with particle-size information.

Scanning Mobility Particle Sizer TSI 3938 with water-based CPC

Nephelometer used to measure fine particulate matter, or PM2.5.B

Fine particulate matter

Measures PM2.5 particles in the air.

Nephelometer Aurora 1000

microAethalometer MA200 used to measure black carbon.C

Black carbon

Soot from transportation and other combustion sources.

microAethalometer MA200

Aerodyne Research CAPS monitor used to measure nitrogen dioxide (NO2).D

Nitrogen dioxide

A marker of traffic and other combustion.

Aerodyne Research CAPS NO₂

Serinus 30 analyzer used to measure carbon monoxide (CO).E

Carbon monoxide

Another tracer of combustion sources.

Serinus 30 analyzer

Insights

Insights into local air pollution

Des Moines AQMS uniquely measures both ultrafine particle number concentrations and particle-size distributions. Because different sources emit particles of different sizes, particle-size distributions serve as a source fingerprint.

The new AQMS near the southern runway provides a unique opportunity to quantify aircraft impacts during north-flow operations.

Chart of ultrafine particle concentrations by hour of day under north-flow and south-flow winds, showing higher concentrations downwind of Sea-Tac Airport.

Community

Community significance

A unique monitoring network

Two monitoring stations at opposite ends of Sea-Tac Airport provide a more complete picture of airport-related air pollution under different wind and runway-operation conditions.

Tracking changes over time

Long-term monitoring will help evaluate how aircraft emissions change as technologies and fuels, including sustainable aviation fuel, continue to evolve.

Working together

The AQMS reflects a collaborative effort among state agencies, community stakeholders and researchers to improve understanding of local air quality.

A community Advisory Board

An Advisory Board will help ensure the project addresses community priorities and that findings are shared with residents.

Monitoring network

Station locations

Stations at opposite ends of the airport allow researchers to compare ultrafine particle patterns under different wind directions and runway operations.

Tip: hover or tab to each marker on the map to see the site and the agency that operates it.

UFP AQMS locations in the Greater Seattle Area with entities managing each site

Data access

Community data access

Community members can view current measurements and explore available data in the public Des Moines air-quality dashboard.

Funding

Funding acknowledgment

This project is supported through Washington’s Climate Commitment Act in partnership with the City of Des Moines, as a Local Community Project sponsored in Legislative District 33 and administered by the Washington State Department of Commerce.

Project partners

Supporting organizations

Washington Climate Commitment Act

City of Des Moines, Washington

University of Washington Department of Environmental and Occupational Health Sciences

Puget Sound Clean Air Agency