Odour Emission Factors: Fundamental Tools for Air Quality Management

As a general rule, emission factors and emission inventories are fundamental tools for air quality management. Emission estimates are important for developing emission control strategies, determining applicability of permitting and control programs, evaluating the feasibility and the effects of appropriate mitigation strategies, and a number of other related applications by different users, including national and local agencies, consultants, and industry. Data from source-specific emission tests or continuous emission monitors are usually preferred for estimating a source’s emissions. However, test data from individual sources are not always available and, even then, they may not reflect the variability of actual emissions over time. Thus, emission factors are frequently the best or only method available for estimating emissions, in spite of their limits (US EPA, 1995). Currently, the most complete compilation of pollutant emission factors is the AP 42 by the United States Environmental Agency, which up to now is constituted by 15 chapters including different sections, each covering a different activity sector, ranging from food and agricultural industries to petroleum industry or waste disposal, and many others. Up to now, this compilation refers to “traditional” pollutants, but not to odours. However, as a matter of fact, odours are now recognized as atmospheric pollutants and are subject to control and regulation in many countries (Nicell, 2009; Sironi et al., 2013). For this reason it appears very important to extend the existing databases of emissions factors to odours, thus defining “odour emission factors” (OEFs).