One key difficulty for process designers when selecting an adsorbent to study more closely in a process is the lack of characterisation. This has also been highlighted by a review from Low et al., which collated the data availability from over 200 adsorbents studied for DAC, and found that very few materials have the characterisation required for process studies. § § There is an overwhelming number of amine-functionalised adsorbents for DAC in literature. Yet, the only universally reported parameter is the uptake capacity at 0.4 mbar of CO2, which, as discussed in this work, is not a critical parameter in isolation. Wu et al. have attempted to develop a standard set of evaluations that should be performed. They identify five key aspects that should be reported: capacity, kinetics, ease of regeneration, stability, and availability. We agree that the evaluation of kinetics is critical. However, applying a standard approach to the evaluation of kinetics is complicated, and the result depends on the conditions and method used. The adsorption half-time at 0.4 mbar of CO2 and a standard temperature such as 25°C in a gravimetric set-up with a small sample, such as 50 mg, to eliminate heat effects could be a simple and quick characterisation method that would allow process designers to screen the literature for adsorbents with fast kinetics quickly. We agree with Wu et al. that CO2 isotherms at a standard temperature such as 25°C should be measured, and particular focus should be on regions of very low pressure (the Henry regime) to capture the affinity. We also agree that stability will be critical to the applicability of any amine-functionalised adsorbent. Conversely, we need to add that H2O adsorption is also vital, and adsorbent designers should consistently start reporting H2O isotherms at a standard temperature such as 25°C. We also see that the co-adsorption effect is significant. It will need to be accounted for when designing the process, but it may be too timeconsuming to measure accurately at the adsorbent development step. Perhaps, with thorough validation, models can be developed to reliably predict this without having to measure them experimentally. The final two key parameters that should be measured from our analysis are the adsorbent density and the thermal conductivity. § § The materials highlighted as having sufficient characterisation by Low et al. are Lewatit® VP OC 1065 and amine-functionalised nanofibrillated cellulose. Email: jpy1@hw.ac.uk RCCS, Heriot-Watt University