Biomass is a promising substitute fuel to reduce fossil CO₂ emissions. However, the ignition and combustion behavior of these substitute fuels differ from fossil fuels. In this work the existing ignition oven method is extended using UVVIS and NIR spectroscopy. The measurement setup is used to investigate wood dust and olive cake regarding the ignition delay time, ignition temperature and occurring species during ignition and combustion. The ignition delay time is determined by using photodiode and spectrometer measurements. One important factor in the determination of the ignition delay time is the applied ignition criterion. A comparative analysis of five ignition criteria commonly applied in the literature reveals differences in the determined ignition delay times and the course of the ignition hyperbolas. In the spectral analysis of the ignition process of wood dust and olive cake the species potassium, sodium, lithium, rubidium, CaOH and CH are identified. The intensity of the molecular radiation is proportional to the content of the species in the fuel. For instance, the CaOH peaks in the spectra of wood dust are higher than those in the olive cake spectra while the CaO content is 2.21 wt% and 1.06 wt% in the ash respectively. The spectral measurements can be used in future work to predict slagging, fouling and corrosion. In subsequent research thermal radiation will be employed to calculate the temperature inside the particle cloud.