Perceived annoyance from environmental odors and association with atmospheric ammonia levels in non-urban residential communities: a cross-sectional study

OBJECTIVE: Odor exposure is an environmental stressor that is responsible of many citizens complains about air pollution in non-urban areas. However, information about the exposure-response relation is scarce. One of the main challenges is to identify a measurable compound that can be related with odor annoyance responses. We investigated the association between regional and temporal variation of ammonia (NH(3)) concentrations in five Danish non-urban regions and environmental odor annoyance as perceived by the local residents. METHODS: A cross-sectional study where NH(3) concentration was obtained from the national air quality monitoring program and from emission-dispersion modelling, and odor pollution perception from questionnaires. The exposure-response model was a sigmoid model. Linear regression analyses were used to estimate the model constants after equation transformations. The model was validated using leave-one-out cross validation (LOOCV) statistical method. RESULTS: About 45% of the respondents were annoyed by odor pollution at their residential areas. The perceived odor was characterized by all respondents as animal waste odor. The exposure-annoyance sigmoid model showed that the prevalence of odor annoyance was significantly associated with NH(3) concentrations (measured and estimated) at the local air quality monitoring stations (p < 0.01,R(2) = 0.99; and p < 0.05,R(2) = 0.93; respectively). Prediction errors were below 5.1% and 20% respectively. The seasonal pattern of odor perception was associated with the seasonal variation in NH(3) concentrations (p < 0.001, adjusted R(2) = 0.68). CONCLUSION: The results suggest that atmospheric NH(3) levels at local air quality stations could be used as indicators of prevalence of odor annoyance in non-urban residential communities.