TRAX

TRAX measures PM2.5 and ozone concentrations with mobile sensors mounted on Utah Transit Authority (UTA) TRAX light-rail trains to characterize high-resolution spatial and temporal air quality variation in Salt Lake County, Utah.

Key Features:

• High-Resolution Monitoring: PM2.5 and ozone sensors mounted on electric light-rail train cars provide continuous, real-time measurements with high spatial and temporal resolution across the metropolitan region.
• Quality Assurance and Validation: Collected data undergo rigorous quality control procedures and are compared with regulatory sensors for validation.
• Comprehensive Coverage: Deployment expanded from two to three train cars, including a north-south rail line, increasing geographical coverage and sampling of previously unmonitored areas.

Scientific Applications:

• Pollution Analysis: Enables analysis of local and regional pollution events including elevated ozone in summer and high PM2.5 in winter influenced by anthropogenic emissions, regional transport of dust and chemical precursors, wildfire smoke, and topography.
• Case Studies: Detects spatial gradients and pollutant hotspots, demonstrated in case studies such as an elevated ozone event and 4th of July 2019 particulate pollution from fireworks.
• Health and Urban Planning: Provides reliable air quality data for health-related research and for informing urban planning on pollution patterns and trends.

Methodology:

Mobile PM2.5 and ozone sensors mounted on light-rail trains collect continuous real-time measurements across the transit network, and datasets undergo quality control and validation via comparisons with regulatory sensors.