Atmospheric hydrocarbon measurements from remote areas are presented and analyzed to determine sources of ambient mixing ratios. Biomass burning appears to make major contributions to free tropospheric hydrocarbon burden over tropical forests and grasslands. Biogenic emissions constitute a large percentage of atmospheric hydrocarbon volume in continental areas of significant productivity. In marine areas studied, ambient hydrocarbons may include contributions from evaporation of dissolved hydrocarbons transported by ocean currents from areas of coastal upwellings or marine pollution. In all cases, hydrocarbons from local sources in major components of the atmospheric hydrocarbon composition.