The release of organic compounds during the drying of biomass is a potential environmental problem, it may contributeto air pollution or eutrophication. In many countries there are legal restrictions on the amounts of terpenes that may bereleased into the atmosphere. When considering bioenergy in future energy systems, it is important that information on theenvironmental e-ects is available. The emissions of organic compounds from di-erent green and dried biofuels that have beendried in hot air and steam medium, were analyzed by using di-erent techniques. Gas chromatography and gas chromatographymass spectrometry have been used to identify the organic matter. The terpene content was signi2cantly a-ected by thefollowing factors: changing of the drying medium and the way the same biomass was handled from di-erent localities inSweden. Comparison between spectra from dried and green fuels reveal that the main compounds emitted during dryingare monoterpene and sesquiterpene hydrocarbons, while the emissions of diterpene hydrocarbons seem to be negligible. Therelative proportionality between emitted monoterpene, diterpene and sesquiterpene change when the drying medium shiftsfrom steam to hot air. The obtained result of this work implies a parameter optimization study of the dryer with regard toenvironmental impact. With assistance of this result it might be foreseen that choice of special drying medium, diversity ofbiomass and low temperature reduce the emissions. A thermo-gravimetric analyzer was used for investigating the biomassdrying rate.