Respiratory, sensory and general health symptoms in populations exposed to air pollution from biodegradable wastes

Background: Adverse health effects of exposure to high levels of air pollutants from biodegradable wastes have been well-studied. However, few investigations have examined effects of chronic exposures to low-to-moderate levels, on health symptoms among residents. Besides, most studies have been ecological and did not investigate whether these potential associations were direct or indirect (stress-mediated). Methods: In this study, individual-specific exposures to a proxy indicator of biodegradable waste pollution (ammonia, NH3) in non-urban residences (n=454) during 2005-2010 were calculated by the Danish Eulerian long range transport model and the local-scale transport deposition model. Logistic regression and mediating analyses were used to examine associations between exposures and questionnaire- based cross-sectional data on odor annoyance and symptoms, after adjusting by person-specific covariates. Results: Individual NH3 exposures were associated with odor annoyance, increased frequency of “eyes itching, dryness or irritation” and “cough” (ORadj =3.72; 95%CI: 2.41–5.75; ORadj = 1.69; 95%CI: 1.09-2.61 and ORadj = 1.75; 95%CI: 1.12-2.74, respectively, for each unit increase in Loge(NH3 exposure)). The results on mediation indicated indirect (annoyance-mediated) associations between exposures and increased occurrence of nose itching, dryness or irritation, runny nose, nausea, headache, dizziness, difficulty concentrating and unnatural fatigue. Conclusions: We found evidence that individual exposures to air pollution from biodegradable wastes are associated with increased occurrence of symptoms among residents. Stress-related mechanisms appear to underlie these effects.