## 3 Results
This finding might be considered as a practical implication for designing the forced ventilation of the ground CRDF storage bin and/or the production hall. In the case of pelletized CRDF, the VOC emissions simulation revealed that pelletization significantly reduces the VOCs concentrations in the storage bin. It has been found that only furan-2-carbaldehyde has the potential to exceed the standard threshold value (Table S2 in the Supplementary Material file 'Model of VOC emissions from CRDF during storage.xlsx'--spreadsheet 'Pelletized CRDF'). The fold of exceedance was above four, and could be considered for improved design of forced ventilation of storage bins. Most likely, much lower ventilation rates would be needed for pelletized CRDF, which could represent cost savings. Another solution could be decreasing the volume of CRDF to the headspace volume ratio in the storage bin, a solution that likely could increase the overall costs. The provided Excel spreadsheet allows such simulation, and may be used for further experiments in that field. These findings have great importance related to practical considerations for the mitigation of VOCs emissions via pelletization. Pelletization improves storage conditions (decrease of volume) and more importantly, the reduction of occupational exposure to VOC emissions from CRDF. Our experiment showed the global effect of the influence of CRDF pelletization on VOCs emission. The release of VOCs during pelletization could be the reason why the emissions measured were lower, but this needs to be investigated in the future. The pelletization reduces also the risk of health standards threshold values exceedance and influences on the technical requirements for forced ventilation of the storage bin. Our experiment was rather exploratory in this field and aimed at testing the practical approaches to VOC mitigation by pelletization. To avoid harmful human exposure and risk of fire and explosion (including dust explosion), it is important to monitor and, if necessary, take actions to reduce VOC off-gassing from different CRDF production steps where exposure might occur [57]. It should be noted that except in the case of VOCs emission, the formation of H\({}_{2}\) and CH\({}_{4}\) formation during CRDF storage should be monitored. Potential VOCs emissions during pelletization can be controlled by typical industrial approaches, such as vents and hoods that are applicable to localized workplace sources of air pollutants. The provided modeling spreadsheet could be improved by, for example, a more advanced model for predicting the VOCs concentration in the air during storage for practical, full production scale and production facility implementation. Further studies should be continued in this field. Emissions during pelletization should also be investigated on an industrial scale. We recommend continuing studies on the mechanism of VOC emissions, including the kinetics of VOCs emission from CRDF. Also, the effects of other types of CRDF biochars on VOC emissions should be studied. In our opinion, this opens a wide niche for investigation both in fundamental science, such as an explanation of the VOCs emission mechanism, and applied science, such as the scaling up of the system for investigating the potential impact of VOCs on workers during CRDF storage and methods of mitigation of VOCs emission as a part of MSW torrefraction technology development. The biochar technology production and its application in the environment is under significant development. However, there is a \"dark side\" of the biochar related to its potential toxicity and emission of pollutants into the environment. Studies in that field should not only focus on biochars from RDF, but also from other organic waste, such as sawdust, sewage sludge, dairy manure, poultry manure, and dried distillers grains with solubles in relation to different torrefraction and pyrolysis temperatures.