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LiOH is known to be one of the most efficient CO2 adsorbent because it reacts with CO2 to form Li2CO3. However, LiOH still suffers from lack of enough hardness for practical use. In this study, various substrates, were modified with LiOH. Their X-ray diffraction patterns were investigated, and LiOH peak was observed from all prepared samples. CO2 adsorption capacity of each prepared sample was measured by monitoring CO2 concentration change during the adsorption process under constant CO2 gas inflow condition. LiOH-modified Al2O3 and zeolite 5A showed good CO2 adsorption performance, while LiOH-modified AC and SiO2 showed relatively poor CO2 adsorption. Al2O3 and zeolite 5A contains many basic functional groups of Al3+, which promote the neutralization reaction with acidic CO2. The effect of carrier gas, carrier gas flow rate, initial CO2 concentration, and amount of LiOH-modified Al2O3 loading was investigated. CO2 adsorption performance was better when the carrier gas was N2, because O2 competes with CO2 on LiOH. CO2 adsorption performance was better with lower carrier gas flow rate, lower initial CO2 concentration, and less loading of adsorbent due to the increase of contact time and contact points.

Although subways have many advantages as a transport system, passengers may be exposed to indoor air pollution. In such cases, the dominant risk factors are associated with particulate matter (PM) bound metals and polycyclic aromatic hydrocarbons (PAHs). In this study, inhalation cancer risks (ICR) were assessed at Seoul metro subway stations (SMS), South Korea, in 2014–2015.