This thesis reports the investigations of sheep wool’s ability to sorb volatile and very volatile organic compounds (v/VOCs). Indoor air quality and occupants health can be adversely affected by the presence of even low gaseous concentrations of v/VOCs. Sheep wool’s fibres, with their keratinous chemical functionalities, provide platforms for sorption of the said compounds. Wools from different breeds of sheep are studied with regards to the sorption of four volatile organic compounds in their gaseous state, which represents a wide range of polarity and basic chemical diversity: formaldehyde, toluene, limonene and dodecane. A gas-tight set-up was constructed and analytical techniques were optimised. It was found that there is variation between the different wool types in addition to difference between scoured and unscoured wools. Total sorption capacity of formaldehyde is also examined, with variations opposing the trend seen for the sorption of the more non-polar VOCs at low concentrations. Sorption patterns were studied with respect to increasing concentrations. Characteristics of the different wool types are reported and linked to the observed sorption behaviour. Moisture uptake is studied across different wool types and the use of the Vrentas-Vrentas mathematical model is discussed. The mean cluster size of water molecules in the wool fibres is compared. The sorption kinetic behaviour of the wool fibres is analysed using the Parallel Exponential Kinetic model, and the sorption parameters were used to calculate the modulus of the wool fibres. Chemical and mechanical modifications along with the use of additives are studied to enhance wool’s sorption ability. Adding polar functionalities onto the fibres’ surface hinders total sorption capacity of formaldehyde and the sorption of all four v/VOCs at low concentrations. Adding a large non-polar functionality also hinders total sorption capacity of formaldehyde, but increases the sorption at low concentrations of non-polar compounds without reducing the sorption of polar formaldehyde. Ball milling increases surface area and the sorption of all four compounds at low concentrations. Carbon fibre as an additive excels at the sorption of non-polar compounds, whereas a coating of chitosan increases the total sorption capacity of formaldehyde without effecting the sorption patterns of any of the v/VOCs at low concentrations. The effect of the modifications on other fibre properties is also reported.