Small size CdS QDs were synthesized by (i) the single source precursor methodology and by (ii) the microwave synthetic route. The consequences of CdS QD direct exposure to air for a period of 7 days were investigated by following the evolution of the photoluminescence (PL) and absortion spectra. For QDs obtained by (i), the excitonic emission band (3.0 ‑ 3.1 eV) decreases in intensity, relatively to the low energy one (2.2 ‑ 2.5 eV) tentatively associated to midgap surface states. This suggests arising of new recombination path(s) associated to degradations during aging, possibly an oxidative formation of a CdO surface layer. On the other hand, no significant change is observed in the absorption spectra. For QDs obtained by (ii), no degradation is revealed by the PL spectra which remain unchanged. On the other hand, the absorption spectra are dominated by an unexplained broad band around 3.6 eV which tends to hide the fundamental excitonic transition one and increases in intensity with aging.