Moss is a bioindicator that can be useful in evaluating air quality in metropolitan areas. One study in Portland used a common moss, Orthotrichum lyellii, to locate sources of cadmium pollution, leading to regulations for glass factories in the area. The current study applied a similar methodology to locate sources of metal contamination in and around the South Puget Sound region. O. lyellii was collected from locations with a wide range of vehicular traffic. Additionally, collection sites were divided between industrial, commercial, residential, and forested areas. Moss samples were dried, digested with acid and peroxide, and analyzed for metal content using ICP-MS. Our study shows increased concentration of trace metals such as titanium and vanadium in industrial areas. Some major metals such as calcium may be more closely linked to vehicle traffic. These results may indicate human health hazards in industrial areas in the South Puget Sound area.