EPA Research Partner Support Story: Long-term performance evaluation of popular air sensor types at locations across the U.S.

Partners: Colorado Department of Public Health and Environment, Delaware Department of Natural Resources and Environmental Control, Georgia Environmental Protection Division, Oklahoma Department of Environmental Quality, Wisconsin Department of Natural Resources (DNR) and Maricopa County (AZ) Air Quality Department
Challenge: Harnessing advances and innovations in air sensor technology for protecting public health
Resource: Long-term performance evaluation of popular air sensor types at locations across the U.S.
Project Period: 2019 – 2021

There is wide interest from air monitoring agencies, researchers, and community groups in deploying smaller, more portable air sensor technologies for community-scale air monitoring projects. First, air sensors need to be thoroughly evaluated in order to understand their limitations and data quality. Many sensor evaluations performed to date have evaluated sensors for short time periods in a single site or region. To be valuable at the local level, more information is needed about how sensors perform long-term and under a wide variety of meteorological conditions and pollutant concentrations.

“As technology and public interest in air quality measurements advance, inexpensive sensors are fast becoming data crowd sourcing tools as well as community outreach resources. Research on the performance of sensors compared to regulatory sensors will be very valuable to states and communities as they look to use these sensors to expand air monitoring opportunities across the country." – Wisconsin DNR, former Environmental Management Division Administrator Darsi Foss

EPA partnered with six air monitoring agencies across the United States to operate five air sensor types alongside standard regulatory monitors so that data could be compared. The commercially available sensors reported concentrations of one or more pollutants and featured variation in sensing elements, sampling techniques, data communication, size, and data correction and display. Data were collected between summer 2019 and spring 2021.The research team shared initial observations and findings with partners and presented results at scientific conferences and during an external EPA webinar in August 2022. In addition, results will be posted on the Air Sensor Toolbox using EPA’s recommended Performance Evaluation Reporting Template and in peer-reviewed scientific journals in 2023. Most importantly, the project illustrates some of the important considerations that should be considered for planning community monitoring projects using this class of technology, including variations in design and performance, common points of failure, suggestions for maintaining sensors for long-term operation, and awareness of the similarities and differences between different sensors and regulatory monitors. Ultimately, the goal is to help manufacturers improve their products, users to choose appropriate sensors for their intended applications, and for air quality managers to advance air quality data collection and accuracy.

More information on this project and air sensor research can be found on the Air Sensor Toolbox.