Analyzing Air Quality in Laredo, Texas

Every day in Laredo, Texas over 20,000 heavy-duty diesel trucks cross the U.S.-Mexico border, but they may be impacting more than just the supply chain.  

A new study aided by Bloomberg Fellow Michelle Mabson and her organization, Earthjustice, with support from the Bloomberg American Health Initiative, analyzed the environmental impact of this traffic and other potential sources of particulate matter on Laredo residents. The study was a part of a year-long community air monitoring project led by the Rio Grande International Study Center to provide residents with data on air pollution spikes and to characterize seasonal air pollution patterns. Historically, the region’s air quality has been assessed through a single federal monitor. While this approach can be effective in smaller communities, Laredo’s more than 3,000 square miles mean residents have had limited access to more accurate, localized data to inform decisions. 

Beginning in 2024, Mabson assisted the Center team with the installation of low-cost PM2.5 sensors capable of detecting fine particle pollution from vehicle emissions, power plants, forest fires, construction dust, and more. These sensors, developed by the Peliter Aerosol Lab at the University of Massachusetts - Amherst, generate real-time data that is available to residents through a bilingual public dashboard. 

The team’s early findings challenged their original hypothesis. Rather than being concentrated around the border bridge, pollution appeared to be distributed across the region. Elevated PM2.5 levels were frequently recorded in areas far from the crossing, suggesting the influence of multiple localized sources of pollution, including vehicular traffic, freight rail, and industrial activity. This shift from a single “hotspot” narrative to a regional exposure profile has important implications for both policy and intervention design. 

Community concerns extend beyond exposure to pollution and include economic stability and public perception. School district leaders, for example, expressed concern that heightened awareness of air quality could influence attendance, while industry stakeholders raised questions about potential regulatory implications. 

The findings also generated concern among local businesses and residents. For many, this study marked the first time they had access to information about air quality in their community. In response, the team adopted a participatory approach, holding meetings with residents and county officials to discuss the significance of the findings and ensure that data collection aligned with community priorities. 

By positioning the data as educational rather than regulatory, the team created space for residents to better understand local air quality and consider potential solutions. Since its launch, the project has seen increased participation from school officials, business leaders, and residents in public forums. 

While the initial data collection phase is complete, the team plans to continue analyzing and sharing data to support ongoing monitoring efforts and contribute to a healthier future for Laredo residents.