A receptor modeling study was conducted in the Tacoma tideflats airshed. The tideflats area is a small but heavily industrial area adjacent to the Commencement Bay waterway of Puget Sound. It is surrounded by urban centers and rural and residential areas. Fine and coarse particles were sampled for 12 hours twice daily beginning at 7 AM and 7 PM from 12/5/89 through 12/15/89 and from 1/2/90 through 1/8/90. Concentrations of total fine particle mass, nitrate and sulfate ions, organic carbon, elemental carbon, and a suite of elements were measured in the fine particle samples. Organic carbon was by far the dominant species in the fine particle fraction. Gaseous species were collected in evacuated canisters concurrently with particulate samples to measure volatile organic species for the purpose of searching for potential motor vehicle tracers. Receptor modeling results indicate that residential woodsmoke, not industrial sources, was the primary contributor (greater than half) to the total fine particle mass. Other major sources identified by receptor modeling are, in order of predominance, aluminum production (one site only), residual oil boilers, motor vehicle exhaust, scrap metal fugitives, and hogged fuel boilers.