Residential exposure to outdoor air pollution from livestock operations and perceived annoyance among citizens

Odor exposure is an environmental stressor that is responsible of many citizens complains about air pollution in non-urban areas. However, there is very little information about the exposure-response relationship. 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 variations of ammonia (NH₃) concentrations in five Danish non-urban regions and environmental odor annoyance as perceived by the local residents. Ammonia concentrations were obtained from the national air quality monitoring program and from emission-dispersion modelling, and odor pollution perception from questionnaires. The model was validated using leave-one-out cross validation (LOOCV) statistical method. 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 NH₃ concentrations. The seasonal pattern of odor perception was associated with the seasonal variation in NH₃ concentrations. The results suggest that atmospheric NH₃ levels measured at local air quality stations or estimated at the residences from emission-dispersion models could be used as indicators of odor annoyance in non-urban residential communities.