Sources of Human Variability in Odor Perception

P. Chrostowski, CPF Associates, Inc.
7708 Takoma Avenue
Takoma Park, Maryland

Air & Waste Management Association 100th Annual Conference
Pittsburgh, PA
June 2007

ABSTRACT

Human response to odor stimuli varies both qualitatively and quantitatively. When taken to its extreme, this can lead to the situation where one person perceives a negative odor whereas another person at the same location perceives no odor at all or even a positive one. This paper reports the results of research to identify the sources of variability in human odor perception and presents quantitative methods for evaluating variability in performing an odor modeling exercise. Variability in perception may be associated with variations in odorant emissions, environmental factors such as atmospheric dispersion and precipitation, exposure factors including location and inhalation rate, physiological factors, psychological and cognitive factors, modifying odors, and disease states. A combination of both psychological and physiological factors leads to both age-based and gender-based variability in odor perception. In addition to age and gender other factors including level of education, smoking behavior, exposure to chemicals, alcohol use, body mass, general and dental health, pregnancy, nutritional status, adaptive processes and use of medications all influence perception of odor. This is often expressed as variability in reported odor thresholds and other quantitative expressions of odor. From a modeling standpoint, this variability can be evaluated using uncertainty propagation techniques such as Monte Carlo analysis. The presentation includes a case study regarding the perception of hydrogen sulfide odor.