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California Border Community Discovers 10x More Air Pollution Events than Detected by Government

April 26, 2018

Community-installed air monitors reveal elevated pollution rates in county with highest child asthma hospitalization in state

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Heber, CA (April 26, 2018) – A network of air monitors installed by community members in California’s Imperial County has found 10 times more episodes of high particulate matter (PM2.5) levels than had been detected by the government’s regulatory monitors, according to preliminary findings presented today by local organization Comité Cívico del Valle, the Public Health Institute’s California Environmental Health Tracking Program (CEHTP) and researchers from the University of Washington. The predominantly Latino Imperial County has exceeded state and federal standards for air quality measures for decades, and it has the highest asthma-related hospitalization rate for children in the state.


Analyses led by University of Washington researchers found:

  • Between October 2016 and February 2017, the community network detected 1,426 high pollution episodes, defined as hourly PM2.5 concentrations above 35 ug/m3—more than 10 times the 116 episodes detected by the government’s monitors.

  • 90% of the time, when an episode was detected by a government monitor, it was only observed by that single monitor. Episodes detected by the community air monitors were observed by at least 5 monitors 68% of the time.

  • The estimated concentration of coarse dust particles (particle sizes between PM2.5 and PM10) was high throughout much of the populated regions of the county.

  • Levels of PM2.5 were estimated to be highest in areas near the Mexican border.


The higher spatial density of the community air monitor network helped it reliably identify more air pollution episodes than the regulatory network. The government has just five regulatory air pollution monitors spread across the county’s more than 4,000 square miles. They measure ambient levels of pollution but do not provide information about air quality in communities that do not have a regulatory monitor. Beginning in 2015, community members and study staff installed 40 of their own air pollution monitors to identify when air pollution levels near vulnerable populations, including at 14 local schools, reach hazardous levels.


“Communities deserve accurate, understandable and actionable information about their local levels of pollution, so they can protect their health,” said CEHTP’s Michelle Wong, MPH. “This new information, brought to light through a scientifically-rigorous, community-designed air monitoring network, means residents in the Imperial Valley are also better equipped to engage with the government and to advocate for better air policy and ultimately, better air.”


Agricultural burning, unpaved roads, and truck and rail transport are some of the known pollution sources that have concerned residents in the areas with high PM10, while pollution from vehicular traffic at the border crossings has been a community concern in areas with high PM2.5. Smaller than the width of a single human hair, PM10 and PM2.5 are so tiny they can penetrate into the respiratory tract and cause significant health problems such as asthma, decreased lung function, and respiratory disease.

Community air monitor system


The community network generates real-time, hourly data, which is available to community members at www.ivan-imperial.org/air. Researchers at CEHTP and the University of Washington, led by Dr. Edmund Seto, worked with Comité Cívico del Valle to ensure that the data captured from the community monitors would be accurate. The careful planning and collaboration with researchers means that the community network’s data are more likely to be both useful and useable by government agencies tasked with protecting health and the environment in the region. 


“This network of monitors has empowered our families with accurate, readily available information about our air quality on a daily basis—but it’s also demonstrated that our air pollution problem is even worse than we thought,” said Luis Olmedo, executive director of Comité Cívico del Valle. “This should give state and local officials an even greater sense of urgency in working to improve our community’s health by eliminating the biggest sources of pollution.”


Part of a 4-year, $2 million study funded by the National Institute of Environmental Health Sciences, the air monitor project is an innovative approach to engaging local residents in scientific data collection. A community steering committee of local residents played a key role, from project design to implementation. The committee and other community members determined the sites where half of the monitors were placed. Comité Cívico del Valle has been responsible for installing and maintaining the monitors.


Share on Twitter: Imperial County has the highest child #asthma ER hospitalization rates in California. Community-installed air monitors found 10x more high pollution episodes than government monitors: bit.ly/Imperial-Air via @PHIdotorg #EnviroHealth



About the California Environmental Health Tracking Program

The California Environmental Health Tracking Program (CEHTP) is a program of the Public Health Institute, in partnership with the California Department of Public Health. The mission of CEHTP is to mobilize data to inform public health.

About Comité Cívico del Valle

Comité Cívico del Valle, Inc (CCV) was founded in 1987 in Imperial County, California, striving to improve the quality of life for disadvantaged communities through a broad range of approaches including civic engagement, outreach, community-based research, policy, citizen science, and crowdsourcing.

About the Public Health Institute 

The Public Health Institute, an independent nonprofit organization, is dedicated to promoting health, well-being and quality of life for people throughout California, across the nation and around the world.