Fine Particulate Matter (PM2.5) is an air pollutant characteristic of vehicle tailpipe emissions which, along with NOx and Ozone, contributes to poor outdoor air quality in car-centric urban areas. While Philadelphia broadly monitors PM2.5 pollution on the city and neighborhood level in certain regions, gaps in the monitoring network limit access to accurate, targeted air quality information along popular mixed-use trails such as the Schuylkill River Trail (SRT) and the Martin Luther King Jr. Dr. (MLK) Trail. Both trails were constructed along roadways, but the SRT is exposed to far more frequent traffic and at a closer proximity to motor vehicles on average compared to the MLK Trail. This presented a unique opportunity to compare patterns of transportation-related air pollution (TRAP) along each trail and to identify regions of the trail network disproportionately impacted by particulate emissions from vehicles. PM2.5 TRAP concentrations were derived from in-situ concentration data of total PM2.5 obtained over twelve collection periods conducted along the MLK and Schuylkill River Trails. Subtracting background concentration values acquired from the Montgomery Drive Air Monitoring Station and normalizing by the background yielded relative PM2.5 TRAP ratios comparable between collection periods. PM2.5 TRAP hotspots were found to be largely concentrated near the intersection of S. Ferry Rd. and Kelly Dr. as well as along Boathouse Row, which were both locations associated with high levels of traffic congestion, particularly during rush hour periods. If possible, users of the Schuylkill River Trail should avoid these regions during periods of high traffic on Kelly Dr. in order to limit excess exposure to PM2.5. This thesis contributes a preliminary investigation into the potential influences of transportation emissions on the Schuylkill River Trail and hopes to encourage further study into air pollution sources and impacts in similar areas across Philadelphia.