In the present study, building on our previous findings, we investigated the role of two SP-A1 (6A2, 6A4) and two SP-A2 (1A0, 1A3) variants, which are frequently observed in the general population [28], on survival, in response to K. pneumoniae alone and in response to filtered air (FA) or ozone (O3)-exposure prior to infection in aged mice (~9–12 months). Here, SFTPA1 is linked to infection.