Biomass combustion emissions arising from naturallyoccurring wildfires, anthropogenically generated prescribedburns, and residential wood combustion contribute greatly toatmospheric fine particulate matter (PM2.5). Wildland fireemissions are different from emissions of residential woodcombustion due to differences in fuel composition andbiomass structure, season of occurrences, time of day, and thelocal environment such as the slope of the ground, ambienttemperature, and wind velocity. These environmental factorslead to some differences in ratios of known molecularmarkers, thus apportionment of wildland smoke usingresidential wood smoke source profiles may miss-representthe impact of smoke during the wildfire season. To providenew insight to biomass combustion emissions, sampling wasconducted in several types of conditions. Carefully controlledconditions were employed for the simulation of residentialwood combustion using a fireplace and a dilution samplingsystem at the Desert Research Institute. Additionally,controlled biomass combustion sampling was conducted at theUSFS Fire Sciences Laboratory Combustion Facility toexamine the emissions of several wildland fuels, includingconifer needles, wildland grasses, and sagebrush. In-fieldopen-area prescribed burning sampling was also conducted inthe Mariposa Sequoia Grove within Yosemite National Park,in central rural Nevada, where desert brushes were thedominate species, and in the Toiyabe National Forest of theSierra Nevada, where conifer trees are the dominate species.In all cases semi-volatile organic compounds (SVOC) sampleswere collected using a PM2.5 cyclone and Teflon-impregnated glass fiber (TIGF) filters followed bypolyurethane foam (PUF) and XAD resin sandwich cartridges.Additional samples were collected using 47mm quartz andTeflon membrane filters for carbon analysis by thermaloptical reflectance (TOR) method and gravimetricmeasurements, respectively. Semi-volatile organiccharacterization was conducted by gas chromatographycoupled with mass spectrometry (GC/MS) using internalstandard quantitation methods with addition of severaldeuterated internal standards prior to extraction. Variability oforganic compounds found in biomass combustion emissionswere examined in this study. Organic makers such aslevoglucosan, methoxylated phenols, methoxylated organicacids, and resin acids vary considerably for wildland fuels.Comparison of these fuels and prescribed burn emissions toresidential wood combustion indicate a large difference in themass percentage of marker compounds such as levoglucosan.Thus, source profiles specific for wildland fires are needed tounderstand the true influence of these emissions to theambient environment.