When emissions containing odorants are released to the atmosphere they can have an impact on the environment. Although under some circumstances this could include an impact on the ecosystem or on human health, that would be a factor of the chemical nature (e.g. toxicity) of the release rather than its odorous nature per se. By convention, the term ‘odour impact’ is restricted to the negative appraisal by a human receptor of the odour exposure. This appraisal, occurring over a matter of seconds or minutes, involves many complex psychological and socio-economic factors. Once exposure to odour has occurred, the process can lead to annoyance, nuisance and possibly complaints.
Review of Odour Character and Thresholds
Scentroid Odour Measurement