concentrations and odor annoyance among non-urban residents in regions I to V. Figure 3a. Daily measured concentrations. Figure 3b. Averaged seasonal concentrations and odor annoyance. The opposite trends in odor annoyance and NH3 emissions observed in autumn in regions III, IV and V are explained by the fact that application of slurry in autumn in Denmark is not generalized as it occurs in spring. Responses on odor annoyance in autumn are more sensitive to the existence (or absence) of winter crops in the proximity of the specific respondents’ houses. Excluding these three data points from the regression analysis between seasonal variations of NH3 concentrations and perceived odor annoyance at each region, increases the coefficient of determination from R2 = 0.68 to R2 = 0.91.