Sunset Laboratory Inc. was founded in 1984 by Bob Cary, a pioneer in the field of organic carbon and elemental carbon (OC-EC) aerosol analysis. The sample sources Sunset Laboratory analyzes by this method are collected in a variety of environments for multiple purposes. Sources range from ambient urban and rural areas to mining sites, work environments, national parklands, forest fire plumes, and sites of other unusual events. Samples are taken for environmental applications such as EPA monitoring programs for visibility and particle loading. We have become experts at analyzing workplace exposure assessments. In the early 1990s, Sunset Laboratory began to make commercially available thermal-optical OC-EC lab instruments, the Lab OCEC Aerosol Analyzer. We sell these instruments worldwide, with a combined analysis base of well over 250,000 filter samples.