Herein, a study of the thermal combustion/pyrolysis behaviour of three lignocellulosic biomass materials was tested. Alongside this, an investigation on the reduction of the subsequently produced pollution emissions was carried out. The lignocellulosic biomasses (miscanthus × giganteus, orange peel waste (OPW) and potato peel waste (PPW)) were physiochemically characterized, along with in-situ gas detection from the combustion/pyrolysis processes. XRD and EDX results showed high level of inorganic salts in the bulk and surface of the samples tested, which had an impact on the combustion/pyrolysis behaviour. Among the three lignocellulosic biomasses tested, OPW showed the highest higher heating value of 17.88 MJ.Kg-1, whereas potato ash was the best candidate as a potential source of potassium (23.8 wt.%) to be used in the fertiliser industry. The EDX results showed that miscanthus was the only lignocellulosic biomass to show high % Si in the surface composition. This was the reason for the low-temperature melting, due to the formation of low fusion-temperature silicate as a result of SiO2, K, Cl and S. Pyrolysis experiments were conducted under pure nitrogen atmosphere, where hydrogen gas was observed in the temperature range of 580-700°C. Combustion experiments were run under air where NOx emissions are generated during the combustion process.To mitigate those emissions, coupling the DeNOx catalyst with urea to construct an in-situ NH3-SCR system during the combustion achieved low levels of NOx emissions.