CO2

Carreiro-Martins, Pedro, João Viegas, Ana Luisa Papoila, Daniel Aelenei, Iolanda Caires, José Araújo-Martins, João Gaspar-Marques, Maria Manuela Cano, Ana Sofia Mendes, Daniel Virella, and others. "CO2 concentration in day care centres is related to wheezing in attending children." European journal of pediatrics. 173 (2014): 1041-1049.