Using drones to measure the relationship between urban air pollution, pollution sources, and vegetation in Seattle

Recent UW research that has identified high concentrations of ultrafine particle air pollution in some Seattle/King County communities has created an urgent need to evaluate the potential efficacy of community-scale air pollution mitigations, including the role that vegetation may play in reducing air pollution. Few studies have considered how trees and shrubs affect ultrafine air pollution, and most have focused on reductions in particles in the horizontal direction to the side of freeways from roadway traffic particle sources, rather than the distributions of particles in vertical and horizontal directions relevant to both roadway and aircraft-sourced particles. We have formed an interdisciplinary team of UW investigators, which includes expertise from Environmental & Occupational Health Sciences, Civil and Environmental Engineering, and Atmospheric Sciences to tackle this challenge and to fill this important knowledge gap for our local communities.

With new funding from UW Earthlab, and in partnership with air quality, health, and community stakeholders, we propose to conduct a study that will utilize an unoccupied aerial vehicle (UAV) – a drone instrumented with high-end air quality sensors, which will allow for efficient measurements at varying altitudes at sites identified by our partners that differ in vegetation density and type and proximity to ultrafine particle sources. Findings from this study will provide local and highly relevant evidence on the effectiveness of urban planning initiatives that may utilize greenery as an approach to address particulate air pollution. Additionally, the results would potentially inform future intervention studies that monitor air pollution changes that occur as a result of planting vegetation, which are starting to occur in cities across the country.

The Reasearch Team and Community Stakeholders on this project include:

Edmund Seto, UW Environmental & Occupational Health Sciences
Tim Larson, UW Environmental & Occupational Health Sciences and Civil & Environmental Engineering
David Shean, UW Civil & Environmental Engineering
Joel Thornton, UW Atmospheric Sciences

El Centro de la Raza
Puget Sound Clean Air Agency
WA Department of Ecology
WA Department of Health

Research finds that community air monitoring helps identify more PM episodes than government monitoring alone

Establishing community-based air quality monitoring networks has largely focused on the benefits of engaging communities in environmental issues, building awareness of air quality-related impacts and environmental disparities. But, has such monitoring really improved our understanding of air quality?

This new paper from our group helps quantify the improved air quality information gained from next-generation community-based air monitoring. The research is based on a dense network of monitors that were established by a collaborative involving our research group and various partners in the Imperial Valley, California in 2016.  We observed that with approximately 10 times as many monitors as operated by government agencies in the region, we observed approximately 10 times as many PM2.5 episodes over a 5-month period.

The monitoring for this study is based on technologies and sensor calibration methods developed in our research group. Our group continues to conduct research and make improvements to our community air monitoring methods.  If interested in learning more about our low-cost monitoring projects in Imperial, San Ysidro/Tijiuana, San Francisco Bay Area, Seattle, Los Angeles, New York City, Chicago, Minneapolis/St. Paul, Baltimore, Winston-Salem please feel free to contact us. 

Imperial study influences passage of AB 617 for Community Air Monitoring in California

As the NIEHS-funded research to establish a network of community-operated PM monitors in Imperial, CA comes to an end this year, efforts have been made to ensure the sustainability of the network.

The team was recognized by the CA State Assembly and Senate on April 26th for the work in Imperial.  Also the work has influenced AB 617, a new rule which was approved by the state legislature in 2017, which requires air districts to implement community and fenceline air monitoring in communities that are classified as highly disadvantaged based on their environmental exposures and impacts as well as social disparities.

Whereas my research group at UW was involved in the development of the network, and managing QA/QC of the data from the monitors during the study, we have transitioned our knowledge of the monitoring to Comite Civico del Valle, who are currently sustaining the monitoring network and are in charge of the data.


US EPA meeting to discuss performance targets for non-regulatory air quality sensors

Over 800 people participated in the June 25-26, 2018 US EPA Air Sensors 2018 meeting, in which performance targets for non-regulatory air quality sensors were discussed.

In recent years, the use of low-cost sensors has grown considerably. Yet, the quality associated with these sensors is not fully known, or is highly variable between different makes/models of sensor, and depends greatly on how the sensors are operated.  Would the establishment of performance targets potential improve the quality of low-cost air quality sensors for non-regulatory applications?

The European Union has made great strides recently to evaluate and form a working group to establish performance targets for air quality sensors.

The US EPA meeting, presentations highlighted recent studies that describe the (good) performance that has been found with current particle matter sensors and ozone sensors, which has allowed for them to be used in a variety of studies and use cases.

In my presentation on “apples to apples vs apples to oranges performance testing”, I first discussed the relative merits of controlled laboratory testing of sensors, which would allow for consistent testing conditions, easy third party verification of testing results, and potentially less uncertain, lower cost, and timely results, and “apples to apples” comparisons between sensor makes/models.  Next, I discussed the importance of field testing in real-world applications that present numerous practical challanges for manufacturers, yet provides reassurance for users that sensors would likely work under real-world scenarios. These field tests would acknowleddge that different use cases in different field settings offer a challenges “apples to oranges” variety of conditions.  If sensors are able to perform well under such challenging and varied testing conditions, they’d likely be useful for non-regulatory applications.

On the 3rd day, smaller panel deliberated the relative merits of sensor evaluation, performance targets, binary vs tiered certification, and other issues.  We are working on a document that would provide summarize some of the perspectives we have on the subject.

NIH NIEHS Partnerships for Environmental Public Health Webinar on Community Air Sensors

The National Institutes of Health’s NIEHS Partnerships for Environmental Public Health (PEPH) program has long been a champion for community-engaged environmental health research.  Today’s webinar highlights the progress of two ongoing projects. PEPH’s description of the webinar is below:



Residents in communities across the country are often curious or concerned about the quality of the air they breathe and how it may affect their health or the health of family and friends. While many locations have air monitors, those monitors are sometimes not in communities of concern. With the advent of smaller, low-cost sensors, residents have become increasingly engaged in monitoring the air quality in their neighborhoods so as to understand and reduce potential health risks.

This webinar will highlight two community-based air monitoring projects. The first is a collaboration among the California Environmental Health Tracking Program (a partnership of the California Department of Public Health and the Public Health Institute); the Comite Civico Del Valle Inc.; the University of Washington; the University of California, Los Angeles; and George Washington University. The second is a partnership between the Harvard T.H. Chan School of Public Health and the Fairmount Greenway Task Force. The presenters will discuss their approaches, the benefits of those approaches, and future opportunities.


The Imperial County Community Air Monitoring Network: A Model for Community-Based Environmental Monitoring for Public Health Action

Paul English, Ph.D., California Department of Public Health
Michelle Wong, California Department of Public Health
Edmund Seto, Ph.D., University of Washington
Luis Olmedo, Comite Civico del Valle

Wheels on the Ground: Citizen Science and the Fairmount Greenway

Ann Backus, Harvard T.H. Chan School of Public Health
Traci Brown, Ph.D., Harvard T.H. Chan School of Public Health
Michelle Moon, Fairmount Greenway Task Force

If interested, there should be a recording of the webinar on PEPH’s website: 

WA State Airport Community Air Quality Study

Sea-Tac airplane. Photo by Paul B.

As the population has grown in Seattle, so too has air traffic at the Sea-Tac International Airport.  According to the Port of Seattle’s statistics for 2016, over 45 million passengers traveled through Sea-Tac. These numbers are up 52% over historical passenger numbers from just 10 years ago.

Increasing air traffic has long been a concerned of residents in neighboring communities.  In particular, residents have been alarmed by the findings of recent studies conducted in other airport communities around the country that have documented elevated ultrafine PM levels along the flight paths near airports, such as LAX.  Yet, because no two airports are the same with respect to how planes land and take-off, the numbers of aircraft that fly in and out, meteorological conditions, local terrain, background air pollution levels, and where people live in relationship to flight paths, extrapolating from others studies to the Seattle context is challenging.

To address this concern and to provide much needed local data, over the next two years, the University of Washington will measure ultrafine PM concentrations in communities within a 10-mile region north and south of Sea-Tac.  The goal of this study will be to identify the extent to which ultrafine PM levels are elevated above background levels of PM.  This includes trying to differentiate aircraft-related PM from the other predominant sources of PM in the area, which include roadway traffic and wood smoke.

Measurements will be collected using a state-of-the-art mobile monitoring platform — a University of Washington car outfitted with high-end air monitoring instruments that can measure the size distribution and counts of ultrafine particles.  This vehicle will traverse the study area throughout the year, allowing the research team to map ultrafine PM levels, and relate the air pollution to varying amounts of air traffic and other factors that may affect ultrafine PM concentrations.

Identifying whether elevated ultrafine PM levels exist in communities around Sea-Tac airport is the first phase of a potentially broader investigation of exposures to aircraft-related pollution and its health effects.  A final report documenting this first phase will be delivered in December 2019.

To learn more about this study, feel free to contact the study leads:

Professor Edmund Seto,
Professor Timothy Larson,

Historical Sea-Tac Passenger Volumes.!/vizhome/Sea-TacAirportActivityReportTP/Cover

Update 9/28/2017:  A resident near the airport emailed me, noting that while passenger volume has trended up, flight operations peaked in 2000.  If you’d like to explore the data, they are available at:!/vizhome/Sea-TacAirportActivityReportTP/Cover



San Ysidro Air Study launches website for real-time air quality monitoring data

The San Ysidro Air Study will be unveiling its new website on June 9, 2017 in an Open House event hosted by study collaborator, Casa Familiar.

This 2-year study funded by CalEPA Office of Environmental Health Hazard Assessment (OEHHA) aims to improve community understanding of air quality at the US-Mexico border region through a community-engaged research process of collecting measurements from 13 next-generation air quality monitors.

The research team includes Casa Familiar, San Diego State University, and the University of Washington.  To learn more about this study, visit the study website, which has webinars, community meeting notes, and links to news stories:

Our new website will provide residents and government agencies in San Ysidro with real-time air quality data in the form of maps and charts.  PM2.5, CO, NO, NO2, and O3 data will be available.  Also, concerned citizens and researchers may request access to historical data collected by the air quality monitoring network via the website.

Additionally, data from the San Ysidro monitoring are being provided to the Identifying Violations Affecting Neighborhoods (IVAN) system for integrated air mapping and environmental reporting among different communities in California.

Our new San Ysidro Air Study data portal is


New York, concrete jungle where dreams are made of… Get’s our latest generation of Community Air Monitors

We’re installing our latest generation of Internet-connected community air monitors (PM particle sizer, 4 gas pollutants) this week in New York City as part of a new MESA study of cardiovascular health led by PI Joel Kaufman at the Unversity of Washington.

Special thanks to PhD student Graeme Carvlin for leading the team of undergrads that are building our current batch of monitors that will be installed in the 6 MESA cities this year, as well as the deployment team and our local collaborators in each of the cities.

These new monitors will enable the next generation of air pollution exposure assessments for multi-city epemiologic studies that are based on real-time, continous spatiotemporally rich environmental data.

Patent Application for a new passive low-cost air pollution sensor

PM air pollution is responsiblity for close to a million deaths and is associated with considerable poor health around the world.

Collaborators from UW Engineering and I filed a new patent for a “Passive Low-Cost Air Pollution Sensor”.  The invention will hopefully pave the way more accurate and precise assessments of PM levels in the developing world, using readily available and inexpensive supplies.

San Ysidro Community-Based Air Monitoring Study at the California-Mexico Border

Funded by the Office of Environmental Health Hazard Assessment of CalEPA, my research group has partnered with Casa Familiar and San Diego State University to conduct a 2-year community-based air monitoring study in the San Ysidro community at the CA-Mexico border.

Motivated by the need to better inform CalEnviroScreen — an Environmental Justice tool developed by CalEPA to map communities disproportionately impacted by environmental health hazards, the study will combine local knowledge from community residents with air pollution monitoring tools and methods provided by academic partners to conduct a year of intensive monitoring within the border community.

Border communities, such as San Ysidro, may face air pollution impacts not felt by other CA communities and existing monitors may not be adequate to measure this impact. Being close to the international border may result in exposure to air pollution from lines of idling vehicles at the Ports of Entry, trade-related commercial trucks, and transport of pollutants from Mexico.

The study will leverage next-generation air quality sensors that measure PM2.5, PM10, CO, NO, NO2, and O3, with high-end research instruments and methods that measure BC, EC/OC, metals, and diesel markers.

The research team recently gave a webinar hosted by CalEPA that discussed Citizen Science, and specifically the goals of the San Ysidro study, the challenges and opportunities for academia and community residents to work together to improve understanding of air pollution in communities and to improve tools like CalEnviroScreen.

The first monitor in this new community monitoring network was officially launched on August 26, 2016.

More information about the study can be found on the project website: 

If you have questions, I’m the study PI: