FOCUS ON ODORS
What is an odor?
An odor is a volatile emanation produced by certain substances, transmitted through the air, and perceived by the sense organ of smell. It is defined not only by the intrinsic characteristics of the stimulus that causes it but also by the receptor system that is sensitive to it.
The human being could differentiate according to experts up to:
1000 billion different smells
Identification depends on each individual's personal history and memory capacities.
Odor is characterize by :
INTENSITY:
The strength at which the odor is perceived
Intensity is not proportional to the quantity of odor molecules
QUALITY:
Recognition of the odor through evocations (floral, putrid...)
HEDONIC TONE:
Perception of pleasantness or unpleasantness
Some information about our relationships with odors
Humans inhale and exhale over 12 cubic meters of air per day through 23,000 breathing movements.
However :
80% of perceived odors = AVERSION
Only 20% of perceived odors = POSITIVE EMOTION
Acceptance of bad odors depends on several factors for individuals. Indeed, the hedonic nature of an odor, related to the notion of well-being, is a significant part of olfactory discomfort and involves psycho-social parameters closely linked to the individual's history.
Complaints about olfactory nuisances are the second most common reason for complaints from neighbors.
Recognize your bad odors
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Ammonia is a colorless gas with a pungent, irritating odor, with the chemical formula NH3. It is widely used in the chemical industry for manufacturing fertilizers, cleaning products, and other chemical compounds. It is generated by some chemical industries (for example, it is found in wastewater from petrochemical activities) as well as numerous agro-industries (production of animal fats, slaughterhouses, rendering plants, fishmongers, canneries, etc.). In nature, ammonia is produced by the decomposition of organic matter. Significant levels of ammonia are therefore found in activities that involve organic matter recycling, such as during the composting process (of urban or industrial sludge, organic waste, green waste), and in livestock farming where animal excreta are the main sources of emissions.
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Methylamine, with the chemical formula CH3NH2, is a colorless gas with a distinctive odor resembling decomposing fish. It is used in the manufacturing of various chemicals, including resins, textile processing products, pesticides, and pharmaceuticals. It is also produced through the decomposition of organic waste.
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Indole (C8H7N) and skatole (C9H9N) are aromatic heterocyclic organic compounds with a strong odor reminiscent of animal tones, often resembling the smell of excrement. At very low concentrations, these molecules exhibit a floral odor commonly used in perfumery as both a fragrance and a fixative. These compounds are naturally present in feces (and are found in activities such as livestock farming and wastewater treatment) as well as in rendering activities.
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Cadaverine, with the chemical formula NH2(CH2)5NH2, has a characteristic odor of decaying meat. It is one of the main chemicals produced during the decomposition of corpses. This molecule can also be found in decomposing foods such as meat, fish, and dairy products. Its emissions are found in activities involving the treatment of urban water and certain industrial waters from the agro-industry, such as during the composting of organic waste.
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Acetic acid (CH3COOH) is an organic chemical compound, the main component of vinegar, which has a pungent odor and a sour taste. It is used in cooking as a preservative and in industry for manufacturing various chemical products. It is primarily generated by agro-industrial activities (production of animal fats, slaughterhouses, rendering plants, canneries), in pig farming, and in wastewater treatment plants.
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Butyric acid (C3H7COOH) is an organic chemical compound with an unpleasant odor reminiscent of rancid butter. It is found in butter, certain cheeses, and vomit. It is used in the production of perfumes and food flavors. This substance is generated by certain agro-industries, agricultural activities such as livestock farming, as well as by water and waste treatment industries.
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Valeric acid (C4H9COOH) is an organic chemical compound with an unpleasant odor resembling sweat. It is primarily used in the synthesis of flavors, softeners, or agrochemical products. It occurs naturally in certain foods, plants, and is used in medicine to treat certain nervous disorders. It is also a by-product of bacterial fermentation. Valeric acid is mainly generated by agro-food industries and industries involved in water and waste treatment.
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Formaldehyde (CH2O) is a colorless gas with a pungent and suffocating odor. Highly reactive, formaldehyde is used in various industrial sectors (manufacturing of adhesives, resins, and some cleaning products). It can also be found indoors. Its reactivity also contributes to its dangerous properties. Formaldehyde is flammable, corrosive, and toxic. At high concentrations, it can be harmful to health, causing irritation and respiratory problems. It is generated by certain chemical industries such as textiles, as well as in water treatment industries.
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Acetaldehyde (CH3CHO) is a highly reactive volatile organic compound with a fruity odor (reminiscent of green apples) at low concentrations. Its olfactory perception becomes pungent and suffocating at high levels. It is naturally produced by certain plants and is present in some foods and beverages, such as ripe fruits and fermented products. Among its uses, acetaldehyde is employed in the production of chemicals and plastics. It is generated by certain agro-industrial activities as well as industries involved in water treatment and organic waste recycling.
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Acetone (C3H6O) is a colorless liquid used in numerous products such as nail polish removers, solvents, and cleaning agents. It is also naturally produced in the human body during the breakdown of fats. Acetone has a characteristic fruity, sweet odor and is highly volatile, meaning it evaporates rapidly when exposed to air. This molecule can be found in certain industrial activities, agricultural practices such as in pig farming, and in wastewater treatment plants.
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Hydrogen sulfide (H2S) is a flammable, toxic, and colorless gas with a strong odor of rotten eggs that can be deadly at high concentrations. The production of H2S can result from several activities, such as anaerobic decomposition of organic matter (particularly generated by organic matter recycling activities, wastewater treatment plants, or certain agro-food industries), industrial activities (H2S is a by-product of many industrial processes, including petroleum refining, paper production, steelmaking, and chemical manufacturing), and agricultural activities (livestock farming).
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Methyl mercaptan (CH3SH) is a gas with a very strong and unpleasant odor, often described as resembling rotten cabbage or natural gas. It is generated by certain industrial activities such as petroleum refining, paper industry, vegetable oil mills, production of animal fats, rendering plants, etc. Additionally, it occurs naturally in some decomposing organic matter (found in wastewater treatment plants, organic waste collection and recycling centers such as landfill sites or composting facilities).
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Ethyl mercaptan (C2H5SH) is a gas with an extremely strong and foul odor, often described as resembling cooked or decomposing cabbage. It is used as an odorant additive in natural gas to facilitate leak detection. Ethyl mercaptan is generated by certain industrial activities such as petroleum refining, paper industry, vegetable oil mills, production of animal fats, rendering plants, etc. Additionally, it occurs naturally in some decomposing organic matter (found in wastewater treatment plants, organic waste collection and recycling centers such as landfill sites or composting facilities).
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Allyl mercaptan (C3H5SH) is a chemical compound with a very strong and unpleasant odor, often likened to garlic or onions. It is also naturally present in certain foods like garlic and onions. Its production results from various natural and anthropogenic activities, including the degradation of organic matter, paper and pulp production, wastewater treatment, processing of foods like garlic or onions, chemical industry for polymers and additives, or combustion of fossil fuels.
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Dimethyl sulfide, with the chemical formula (CH3)2S, is a volatile organic compound with a strong and unpleasant odor, often described as similar to cooked cabbage or decomposing vegetables. It is found in certain plants, seafood, and is also produced during the decomposition of organic matter. Dimethyl sulfide is generated by industrial activities such as petroleum and natural gas production, paper and pulp production, rendering plants, slaughterhouses, as well as activities involving the collection, storage, and recycling of organic waste.
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Thiolane (C4H8S) is a saturated heterocyclic compound belonging to the thioether family. It is present in petroleum and natural gas and is also produced by the degradation of certain types of algae. Thiolane is synthesized industrially and used in the manufacturing of various chemicals, including rubbers, resins, and plasticizers. It can be generated during the treatment of urban and industrial wastewater.
