We found: 1) ozone exposure followed by K. pneumoniae infection decreases survival and alveolar macrophage phagocytic function of SP-A (-/-) mice compared to filtered air exposure (p < 0.05), and females are more affected than males; 2) SP-A (-/-) mice (exposed either to ozone or FA) are more susceptible to infection with K. pneumoniae than wild type (WT) mice regarding their survival rate and macrophage phagocytic function; the phagocytic function of FA SP-A(-/-) is similar to that of ozone exposed WT. This evidence concerns the gene SFTPA2 and susceptibility to pneumonia measurement.