Abstract. Wood combustion emissions can induce oxidative stress in the human respiratory tract caused by reactive oxygen species (ROS), either directly or after oxidation in the atmosphere. To improve our understanding of the ROS generation potential of wood combustion emissions, a suite of smog chamber (SC) and potential aerosol mass (PAM) chamber experiments were conducted under well determined conditions for different combustion devices and technologies, different fuel types, operation methods, combustion regimes, combustion phases and aging conditions. The ROS content as well as the chemical properties of the aerosols were quantified by a novel ROS analyzer and a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS). For all eight tested combustion devices, primary ROS concentrations substantially increased upon aging. The level of primary and aged ROS emission factors (EFROS) were dominated by the combustion device (within different combustion technologies) and to a greater extent by the combustion regimes: the variability within one device was much higher than the variability of EFROS from different devices. Aged EFROS under bad combustion conditions were ~ 2–80 times higher than under optimum combustion conditions. EFROS from automatically operated combustion devices were on average one order of magnitude lower than those from manually operated appliances, which indicates that automatic combustion devices operated at optimum conditions to achieve near-complete combustion should be employed to minimize ROS emissions. The parameters controlling the ROS formation in secondary organic aerosol were investigated by employing a regression model, including the fractions of the mass spectrometric signatures m/z 44 and 43 in SOA (f44-SOA and f43-SOA), the OH exposure, and the total organic aerosol mass. The regression model results of the SC and PAM chamber aging experiments indicate that the ROS content in SOA seems to increase with the SOA oxidation state, which initially increases with OH exposure and decreases with the additional partitioning of semi-volatile components with lower ROS content at higher OA concentrations, while further aging seems to result in a decay of ROS. The results and the special data analysis methods deployed in this study could provide a role model for ROS analysis of further wood or any other combustion studies investigating different combustion conditions and aging methods.