What Animals Smell
Ozonics is constantly participating in research with various agencies and private entities to determine the molecular structures that animals smell that allow them to identify humans as humans and a threat. As pertinent research develops, we will share it here for the use of the industry and marketplace.
Ozone and human scent
By Dr. Francis Y. Huang, chemical oxidation expert at a private research organization in San Antonio, TX.
Ozone(O3) is a strong, gaseous, oxidizing chemical that is prone to react with chemicals that have unsaturated molecular structures. Ozone has been used to treat drinking water and for wastewater treatment (e.g. von Gunten, 2003; Ternes et al., 2003; Huber et al, 2005; Li et al., 2008), indoor air odor abatement (as measured by olfactometry and modern sensitive instruments), and nuisance odor elimination in conjunction with animals (e.g. Wu et al., 1999; Liu et al., 2011; Feilberg et al., 2010). Even at low levels (parts per million or even parts per billion), ozone has been found to react with surface and airborne chemicals in buildings and aircraft cabins (e.g. Wisthaler et al., 2005; Uhde and Salthammer, 2007; Weschler et al., 2007).
Ozone reacts with many volatile organic compounds commonly produced in nature, resulting in either total destruction or chemical alteration such that these compounds lose their characteristic chemical properties. For example, in field tests on flowers, when floral hydrocarbons, the compounds which provide essential signals to attract pollinators, come in contact with ozone, pollinator foraging efficiency is drastically reduced. (McFrederick et al, 2008). Such loss of floral scent signals might force insect pollinators to spend more time searching for flower patches and less time foraging.
The hydrocarbon compounds linalool, β-myrcene, and β-ocimene are known to be common scents released from flowers. They all have unsaturated chemical structures and readily react with oxidizing chemical agents. Similarly, there are many such chemicals emitted from warm-bodied animals. These chemicals are responsible for body scents or odors, particularly in axillary sweat and urine. Scientists have identified several hundreds of these compounds and can use them as individual or gender fingerprints or markers, as well as pregnancy or health abnormality indicators (e.g., Ebling, 1989; Curran et al, 2005; Penn et al. 2006; Vagilio, 2010). Many of these compounds are found to readily react with strong oxidizing chemical agents, too. The chemicals found in human odor or scent can be categorized in several classes of chemical structure, including alcohols and phenols (phenolics), aldehydes, ketones, esters, hydrocarbons, heterogenic organics (indolics), and organic fatty acids. Like floral scents, many of them have very complex chemical structures, particularly in unsaturated forms, which can be easily attacked by ozone, even at low levels.
As mentioned previously, ozone is known to react readily with odor-causing chemicals in farm animal waste and airborne odorants, particularly indolic and phenolic organics which all have unsaturated chemical structures. It stands to reason, then, that ozone should have the same effect on human odor and scent as they contain compounds of the same chemical classes, although not all the compounds found in human odor and scents are also found in farm animal waste or odor. Scientists do not know why wild and some domestic animals are extremely sensitive to human odors and scents, but we can logically speculate that there are strong differences between the olfactory capabilities of animals and humans and the sensitivity of odor and scent detection must be chemical related. Using a “key-to-lock” analogy: if human odor and scent contain specific components that are readily detected by animals (unfortunately, to date, no scientist can definitively identify and isolate these components due in part to their structural complexity and extreme low odor threshold), the key (the chemicals) must fit the lock (the animal smell sensors) to deliver identifiable signals. What if the key is destroyed or altered by ozone? If so, then the key will not fit the lock and subsequently no detectable odor or scent will be recognized!
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Feilberg, A., Dorno, N., Nyord, T., 2011, Odor emission following land spreading of animal slurry assessed by proton-transfer-reaction mass spectrometry (PTP-MS), Chemical Engineering Transactions, 23, 111-116.
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Curran, A. M., Rabin, S. I., Prada, P. A., Furton, K. G., Comparison of the volatile organic compounds present in the human using SPME-GC/MS, Journal of Chemical Ecology, 31(7), 1607-1619
Penn, D. J., Oberzaucher, E., Grammer, K., Fischer, G., Soini, H. A., Wieesler, D., Novotny, M. V., Dixon, S. J., Xu. Y., Brereton, R. G., 2006, Individual and gender fingerprints in human body odour, Journal of the Royal Society Interface, 4(13), 331-340
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