The Odor Awareness Scale (OAS) is a questionnaire designed to assess individual differences in awareness of odors in the environment. The theory that odor awareness can be distinguished in awareness of negative (to be avoided) odors and positive (to be approached) odors was tested using confirmatory factor analysis (CFA) on the 34-item questionnaire after completion by 525 respondents. CFA (after deletion of 2 items) showed good fit of the 2-factor theory, resulting in a positive awareness subscale (11 items, Cronbach's alpha = .77) and a negative awareness subscale (21 items, Cronbach's alpha = .80). Furthermore, reports of sickness from environmental odors were correlated with the negative odor awareness factor, not the positive odor awareness factor. Respondents scoring high on the overall sum score of the OAS showed significantly better olfactory performance on an odor perception test battery than respondents with a low score. These results suggest a causal relation between awareness of potentially negative odors, olfactory performance and experiencing health effects from environmental odor exposure, that warrants further investigation.