As shown in Figure (a), seven chemical features, including OMS, parallel benzene ring (PAR), metalelectronegative atom-metal (M-X-M), uncoordinated nitrogen, azole linker, methyl functional group (-CH3), and electronegative functional group (-EN), were identified in the promising MOFs. 4 of them (OMS, PAR, M-X-M, and uncoordinated nitrogen) were suggested in previous screening works, and others (azole linker, -CH3, and -EN) were intermittently described in experimental works. Among these, OMS and the azole linker appeared in nearly half, or more, out of the MOF candidates. The OMS, a well-known chemical moiety, facilitates strong interactions between positively charged metal atoms and negatively charged oxygen atoms in gas molecules. However, the stronger interaction between the more negatively charged O atom in H2O, compared to that in CO2, leads to H2O typically interacting more strongly with OMS than CO2. This suggests that OMS utilization in DAC application should be approached with caution.