Objectives: Health effects associated with air pollution at exposure levels below toxicity may not be directly related to level of exposure, but rather mediated by perception of the air pollution and by top-down processing (e.g., beliefs that the exposure is hazardous). The aim of the study was to test a model that describes interrelations between odorous air pollution at non-toxic exposure levels, perceived pollution, health risk perception, annoyance and health symptoms.
Methods: A population-based questionnaire study was conducted in a Swedish community of residents living near a biofuel facility that emitted odorous substances. Individuals aged 18-75 years were selected at random for participation (n = 1,118); 722 (65 %) agreed to participate. Path analyses were performed to test the validity of the model.
Results: The data support a model proposing that exposure level does not directly influence annoyance and symptoms, and that these relations instead are mediated by perceived pollution and health risk perception.
Conclusions: Perceived pollution and health risk perception play important roles in understanding and predicting environmentally induced annoyance and health symptoms in odorous environments at non-toxic levels of exposure.