The prescribed burning of wildland areas is an essential tool of forest and wildlands management, providing ecological benefits and reducing wildfire risk. Smoke from prescribed burns also has a significant impact on local air quality. The generation and transport of particulate matter (PM) emissions is of special concern, as PMs have been identified as a significant public health risk. Particulate emissions factors provide a measure of particulate production in relation to the amount and type of fuel burned. Experiments to measure particulate emissions factors of common wildland fuels from the southwestern United States were conducted at the US Forest Service Fire Science Laboratory in Missoula, MT. The environmentally controlled combustion laboratory consisted of a fuel bed placed below an adjustable exhaust flue. Instrumentation included laser photometer particle detectors, aerosol mass spectrometers, open-path FTIR, fast mobility particle sizers, condensation particle counter, particle mass monitor, filter sampling, and fuel bed load cells. Particulate emissions were measured using direct (particle capture) methods. This presentation will focus on newly obtained emissions factors of PM2.5, using the direct method, for chaparral and oak woodland fuels from California and Arizona. Emissions factors will be compared with published EPA AP-42 values. In general, the newly calculated emission factors are lower than those published in AP-42.