Trailer for Researching Environmental Equity (TREE) Project

Get in the know!

Results Workshops

The Puget Sound Clean Air Agency conducted air quality monitoring using the TREE trailer and the community-led monitoring in four neighborhoods. We are coming back to your community after conducting community-led monitoring to report our findings.

Join us for an in-person, air monitoring workshop to discuss the air quality results in your neighborhood. Click the button below to sign up for a workshop near you:

The results are in!

View the full report

This document provides a comprehensive overview of the community‑directed air monitoring workshops and the analysis completed in collaboration with the University of Washington. Inside, you’ll find information on key sources of air pollution and the associated health risks in the four participating communities of the project.

View the reports in each community

You can also view the summarized report for each community, available in different languages:

LAKEWOOD *View the report in English* *View the report in Spanish*	CENTRAL DISTRICT *View the report in English* *View the report in Spanish*
CHINATOWN-INTERNATIONAL DISTRICT *View the report in English* *View the report in Chinese*	DUWAMISH VALLEY *View the report in English* *View the report in Spanish* *View the report in Vietnamese*

What is the TREE project?

The Trailer for Researching Environmental Equity (TREE) is a project to increase community-directed air monitoring and interest in air pollution, especially in areas that are overburdened. This is from a 3-year grant funded by EPA and Inflation Reduction Act funds.

We deployed TREE trailer that served as an air monitoring center, equipped with research-grade air monitors. Community youth groups were involved in walking tours where they used handheld air monitors to “branch” out from the TREE and explore the neighborhood.

What did we monitor?

The TREE trailer is equipped with monitors to measure fine particles, black carbon (“soot” from diesel exhaust), ultrafine particles, nitrogen dioxide, carbon dioxide, and PM10 metals. We also provided hand-held monitors to measure air quality “on the go”.

This has been community-directed so based on the interests of the community, we explored trends trying to identify pollution sources or trying to map air monitor measurements. The equipment on the trailer is ideal for identifying transportation sources (such as diesel exhaust from trucks, cars, airplanes, trains, generators, or forklifts), or wood smoke.

We are now sharing results and resources in accessible formats, including in multiple languages, to ensure all community members can use the results.

Where did we monitor and when?

We monitored in the following neighborhoods using both the TREE trailer and the community-led monitoring as follows:

Lakewood, April - July 2024
Seattle Chinatown-International District. June - August 2024
Seattle Duwamish, September - October 2024
Seattle Central District, December 2024 - February 2025

TREE trailer and Community-monitoring Air Quality Data

If you are interested in checking out the real-time TREE trailer air-quality data and the community monitoring data carried out by several youth groups, we partnered with, please view the app.

On the link, you will be able to select time of interest, location, and different pollutants (PM2.5, NO2, CO2, Black Carbon, Ultrafine particles) to either get an idea of the air quality over time (using the trailer data) or spatially (using the community monitoring data). While more accurate instruments are in place in the trailer, lower-cost and less accurate air monitors were used during community-monitoring walkarounds.

Please note that at this time, all the data are considered preliminary, and we will be updating this page with the final data soon once quality control checks have been performed and the data analysis is conducted.

If you have any questions or suggestions to improve the data app, please contact us and we would be happy to help.