Wastewater treatment plants (WWTPs) produce gaseous emissions that might be olfactory annoying to the surrounding population. Current odour assessment methodologies are based on costly and infrequent olfactometry measurements involving human panels, and continuous monitoring of few gases via fixed gas detectors installed on the plant.

   This leads to odour measurements with low temporal and spatial resolution, hindering an accurate characterization of the odour episodes. The main goal of the SNIFFDRONE project, presented in this paper, is to develop a drone with olfaction capabilities to acquire spatially-dense odour measurements and localize the source of odour nuisances in WWTPs.

    In the Flemish legislation, no odour assessment framework is implemented, despite that odour-related permit applications require the inclusion of an odour impact study. For livestock farming, odour emission factors, derived from olfactometric measurements (ou_E), are widely used. Contrastingly, the available assessment tools, based on earlier odour impact research, utilize sniffing measurements (se).

   To allow comparison between the two units of odour, it is assumed that 1 ou_E equals 1 se. For most groups of livestock animals with a rather constant growth cycle (e.g. pigs), this comparison is deemed valid and suitable for evaluating the odour impact. However, the theoretical assessment of broiler chicken emissions can be questioned, as the olfactometric emission factor of 0.33 ou_E/s.animal results in almost no odour impact.