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 thermal-optical technique developed by Bob and others at the Oregon Graduate Center was adopted as the analytic method for OC-EC measurements by the National Institute for Occupational Safety and Health (known as NIOSH method 5040). In recognition of this achievement Bob received the 1996 Alice Hamilton Award as a co-author of this method. 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. In 2000, we developed Model-4 Semi-Continuous OC/EC Field Analyzer, a semi-continuous OC-EC analyzer for near real-time, in-situ measurement of carbon aerosol. The time-resolution capability and laser-based pyrolysis correction techniques of this instrument provide refined information about particle origins, health exposures, and changes in air quality. Our instruments have become the premiere analytic equipment used for OC-EC on six continents and more than 40 countries, and are ready for use with the NIOSH method 5040, IMPROVE and EUSAAR 2 protocols. Highly configurable operating parameters also allow for custom designed analysis.