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67-557: Renuzit is an American brand of air fresheners produced by Henkel North American Consumer Goods . The Renuzit brand once also included a solvent -based spot remover and cleaner. Renuzit cleaning fluid was originally produced by Radbill Oil Co. of Philadelphia in 1932, which became Renuzit Home Products Company sometime before 1947. The company was acquired by Drackett in 1969 (a child company of Bristol-Myers , which merged with Squibb in 1989). In 1992, Bristol-Myers Squibb sold Drackett to S. C. Johnson & Son , at which point,

134-432: A California law passed in 2017. A California study in 2006 found that the prominent products of the reaction of terpenes found in air fresheners with ozone included formaldehyde, hydroxyl radical , and secondary ultrafine particles . It is not clear if manufacturers will need to list such chemicals which are not ingredients, but form during deployment and are thus able to affect human health. In 2009, Stanley M. Caress of

201-623: A candle flame or some other heat source to heat and vaporize a fragrance formulation, incense burners , wall plug-ins which either use piezoelectric technology to aerosolize fragrance or heat to vaporize it, fragrance impregnated gels which release fragrance as the gel evaporates sometimes with the help of an electric fan, wick and reed diffusers which release fragrance by evaporation from fragrance-soaked wicks or wooden reeds; and fragrance impregnated materials like floor wax, paper, plastics, wood which release fragrance by off gassing ; and lastly nebulization systems which convert liquid fragrances into

268-487: A chemical that binds to copper in the mouse nose, so that copper was not available to the receptors, the authors showed that the mice could not detect the thiols without the copper. However, these authors also found that MOR244-3 lacks the specific metal ion binding site suggested by Suslick, instead showing a different motif in the EC2 domain. Gordon Shepherd proposed that the retro-nasal route of olfaction (odorants introduced to

335-568: A difference between the ports. The gas-diluting ratio is then decreased by a factor of 1.4 or two (i.e., the concentration is increased accordingly). The panelists are asked to repeat the test. This continues until the panelists respond with certainty and correctly twice in a row. These responses are used to calculate the concentration of the odor in terms of European odor units (OU E /m , where 1 OU E /m ≡40 ppb/v n-butanol). Humans can discriminate between two odorants that differ in concentration by as little as 7%. A human's odor detection threshold

402-448: A dozen organisms. They are seven-helix-turn transmembrane proteins. But there are no known structures for any olfactory receptor. There is a conserved sequence in roughly three quarters of all ORs. This is a tripodal metal-ion binding site, and Suslick has proposed that the ORs are in fact metalloproteins (most likely with zinc, copper, and manganese ions) that serve as a Lewis Acid site for

469-417: A gas to fill any empty space. Less common compressed gas propellants work similarly but maintain pressure by filling the empty space without liquefying. The propellant in a true aerosol is mixed with the air freshener, so it must also not react with the product. Sometimes, multiple propellants are combined. CFCs were once popular propellants but are no longer widely used because of their damaging effects on

536-578: A male advantage. A 2019 meta-analysis claimed that the differences in olfaction are extremely small, but confirmed a small advantage for women. Pregnant women have increased smell sensitivity, sometimes resulting in abnormal taste and smell perceptions, leading to food cravings or aversions. The ability to taste also decreases with age as the sense of smell tends to dominate the sense of taste. Chronic smell problems are reported in small numbers for those in their mid-twenties, with numbers increasing steadily, with overall sensitivity beginning to decline in

603-422: A military technology for dispensing insecticides . The product delivered a fine mist of aroma compounds that would remain suspended in the air for an extended period of time. In the 1950s, many companies began to add chemicals that counteract odors to their fragrance formulas. These chemicals, intended to neutralize or destroy odors, included unsaturated esters , pre-polymers, and long-chain aldehydes . In

670-545: A nuisance, depends also on the frequency, concentration, and duration of an odor. The perception of irritation from odor sensation is hard to investigate because exposure to a volatile chemical elicits a different response based on sensory and physiological signals, and interpretation of these signals is influenced by experience, expectations, personality, or situational factors. Volatile organic compounds (VOCs) may have higher concentrations in confined indoor environments, due to restricted infiltration of fresh air, as compared to

737-412: A particular sensation. When odorants are mixed, a habitual odorant is blocked. This depends on the strength of the odorants in the mixture, which can change the perception and processing of an odor. This process helps classify similar odors as well as adjust sensitivity to differences in complex stimuli. The primary gene sequences for thousands of olfactory receptors are known for the genomes of more than

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804-782: A similar fashion except that the actuator is a pump which when pressed a few times creates the pressure to aspirate the fragrance from the container through a tube into the actuator and spray nozzle. Because the container is not constantly under pressure it may be made of glass or plastic as well as metal. The mist created contains droplets 50 to 150 micrometres in diameter. In addition to the fragrances , adsorbents, oxidizers, surfactants , and disinfectants listed above, air fresheners can also contain aerosol propellants , preservatives , and solvents . Air fresheners use both synthesized and organically occurring fragrances. Common fragrances used include lyral and citronellal . Preparations often include terpenes such as limonene . A propellant

871-402: A single compound, but instead the whole odorous mix. This does not correspond to the concentration or intensity of any single constituent. Most odors consist of organic compounds , although some simple compounds not containing carbon, such as hydrogen sulfide and ammonia , are also odorants. The perception of an odor effect is a two-step process. First, there is the physiological part. This

938-432: A threshold, the neuron fires, which sends a signal traveling along the axon to the olfactory bulb , a part of the limbic system of the brain. Interpretation of the smell begins there, relating the smell to past experiences and in relation to the substance(s) inhaled. The olfactory bulb acts as a relay station connecting the nose to the olfactory cortex in the brain. Olfactory information is further processed and forwarded to

1005-412: A vapor in a cold process without the use of heat. Instant action systems are mainly aerosol or atomizer sprays. The aerosol spray uses a propellant and fragrance packaged under pressure in a sealed metal container with a valve which is opened by pressing down a button which contains a spray nozzle – the actuator. When the container's valve is opened by pressing the actuator, fragrance is forced through

1072-428: Is a critical element in assessing an odor. This property is the ability to distinguish different odors and is only descriptive. First, a basic description is used—such as sweet, pungent, acrid, fragrant, warm, dry, or sour. The odor is then referenced to a source such as sewage or apple which can then be followed by a reference to a specific chemical such as acids or gasoline. Most commonly, a set of standard descriptors

1139-399: Is a primary evolutionary sense . The sense of smell can induce pleasure or subconsciously warn of danger, which may, for example, help to locate mates, find food, or detect predators. Humans have an unusually good sense of smell considering they have only 350 functional olfactory receptor genes compared to the 1,300 found in mice, for example. This is despite an apparent evolutionary decline in

1206-487: Is a primary factor in the sensation of comfort. Olfaction as a sensory system brings awareness of the presence of airborne chemicals. Some inhaled chemicals are volatile compounds that act as a stimulus, triggering unwanted reactions such as nose, eye, and throat irritation . Perception of odor and of irritation is unique to each person, and varies because of physical conditions or memory of past exposures to similar chemicals. A person's specific threshold, before an odor becomes

1273-427: Is assigned. Odor intensity can be divided into the following categories according to intensity: Odor intensity is determined in a laboratory by specialists who have been trained to accurately define intensity. Hedonic assessment is the process of rating odors according to a scale ranging from extremely unpleasant to extremely pleasant. Intensity and hedonic tone, whilst similar, refer to different things: that is,

1340-415: Is diluted to a detection or recognition threshold . The detection threshold is the concentration of an odor in air when 50% of a population can distinguish between the odorous sample and an odor-free reference sample. The recognition odor threshold is usually a factor of two to five higher than the detection threshold. The measurement of odor concentration is the most widespread method to quantify odors. It

1407-432: Is fatigued, but recovers if the stimulus is removed for a time. Odors can change due to environmental conditions: for example, odors tend to be more distinguishable in cool dry air. Habituation affects the ability to distinguish odors after continuous exposure. The sensitivity and ability to discriminate odors diminishes with exposure, and the brain tends to ignore continuous stimulus and focus on differences and changes in

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1474-469: Is standardized in CEN EN 13725:2003. The method is based on dilution of an odor sample to the odor threshold. The numerical value of the odor concentration is equal to the dilution factor that is necessary to reach the odor threshold. Its unit is the "European Odour Unit", OU E . Therefore, the odor concentration at the odor threshold is 1 OU E by definition. To establish odor concentration, an olfactometer

1541-622: Is the detection of stimuli by receptors in the nose. The stimuli are recognized by the region of the human brain which handles olfaction. Because of this, an objective and analytical measure of odor is impossible. While odor feelings are personal perceptions , individual reactions are usually related. They relate to things such as gender , age, state of health, and personal history. The ability to identify odor varies among people and decreases with age. Studies claim that there are sex differences in odor discrimination, and that women usually outperform men. Conversely, there are some studies claiming

1608-404: Is the lung technique, where the sample bag is placed in a sealed drum, where a vacuum is created outside the bag, which fills under expansion, and draws into itself the sample from the source. Critically, all components which touch the odor sample, must be odor free, which includes lines and fittings. In comparing the odor emitted from each port, the panelists are asked to report if they can detect

1675-536: Is to measure the odor concentration at the emitting surface, and combine this with the volumetric flow rate of air entering the biofilter to produce an emission rate. Indirect sampling is often referred to as back calculation. It involves the use of a mathematical formula to predict an emission rate. Many methods are used, but all make use of the same inputs which include surface roughness, upwind and downwind concentrations, stability class (or other similar factor), wind speed, and wind direction. The human sense of smell

1742-418: Is used which employs a group of human panelists. A diluted odorous mixture and an odor-free gas— n-Butanol —as a reference are presented from sniffing ports to a group of panelists who are sensitive in odor perception. To collect an odor sample, the samples are collected using specialized sample bags, which are made from an odor free material, e.g., Teflon . The most accepted technique for collecting odor samples

1809-531: Is used, which may range from "fragrant" to "sewer odor". Although the method is fairly simplistic, it is important for the FIDOL factors to be understood by the person rating the smell. This method is most commonly used to define the character of an odor which can then be compared to other odors. It is common for olfactometry laboratories to report character as an additional factor post sample-analysis. Different categorizations of primary odors have been proposed, including

1876-401: Is usually a liquid gas substance used to physically propel the product out of an aerosol spray. The substance chosen needs to be a gas that turns to liquid when pressurized with a relatively low amount of pressure, safe for domestic use. The propellant is a liquid when under pressure in the can, but maintains the pressure in the can (and thereby its spraying ability) by turning partially back to

1943-609: Is variable. Repeated exposure to an odorant leads to enhanced olfactory sensitivity and decreased detection thresholds for a number of different odorants. It was found in a study that humans who were unable to detect the odor of androstenone developed the ability to detect it after repeated exposure. People who cannot smell are said to be anosmic . There are a number of issues which have to be overcome with sampling, these include: Issues such as temperature and humidity are best overcome using either pre-dilution or dynamic dilution techniques. Other analytic methods can be subdivided into

2010-1090: The Federal Trade Commission ordered S.C. Johnson to divest itself of Renuzit and certain other products within a year, and not purchase any other company making air fresheners for 10 years. The following year, S.C. Johnson sold Renuzit to the Dial Corporation . In 2004, Dial became a subsidiary of Henkel . Air freshener There are many different types of air fresheners that deliver their active ingredients in different ways, including sprays, candles, gels, passive and active evaporating diffusers, atomizers, automatically timed metered aerosol dispensers, electric fan air fresheners, and plug-ins. Air fresheners are used in domestic and commercial settings and in both small and large spaces. Some air fresheners are produced for specific spaces and odors, such as car fresheners and urinal deodorizer blocks . Some air fresheners contain ingredients that provoke allergy and asthma symptoms or are toxic. Air freshening also involves

2077-1009: The Sierra Club , Alliance for Healthy Homes, and the National Center for Healthy Housing , the NRDC filed a petition with the U.S. Environmental Protection Agency and the Consumer Product Safety Commission to report the findings. Research at the University of Colorado at Boulder revealed the carcinogenic nature of paradichlorobenzene (PCDB) and naphthalene , present in some types of air fresheners. The pesticide substances were mainly used in mothballs but also in room sprays and toilet rim blocks. The University of Bristol 's Avon Longitudinal Study of Parents and Children (ALSPAC) found that exposure to volatile organic compounds through frequent use of air fresheners and other aerosols in

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2144-720: The University of West Georgia and Anne C. Steinemann of the University of Washington published results from two national epidemiological studies of health effects from exposure to air fresheners. They found that nearly 20 percent of the general population and 34 percent of asthmatics report headaches, breathing difficulties, or other health problems when exposed to air fresheners or deodorizers. Air freshener aerosols with certain propellants are susceptible to misuse as an inhalant . Air fresheners have also been used to cause aerosol burn . In rare cases aerosol burns are reported to have been caused by air freshener canisters exploding. Removing

2211-492: The limbic system , the area of the brain that governs emotional responses. Some believe that these messages have the power to alter moods, evoke distant memories, raise spirits, and boost self-confidence. This belief has led to " aromatherapy ", wherein fragrances are claimed to cure a wide range of psychological and physical problems. Aromatherapy claims that fragrances can positively affect sleep, stress, alertness, social interaction, and general feelings of well-being. Evidence for

2278-410: The ozone layer and resulting bans. Current propellants used in air freshener sprays include: Note that while bag-on-valve systems may use compressed air , nitrogen or carbon dioxide or other substances to squeeze the air freshener from the bag, these are not strictly ingredients because they are not mixed with the air freshener, and remain in the can. Preservatives prevent the decomposition of

2345-425: The 1980s, the air freshener market shifted back away from aerosols due to concerns over the destruction of the ozone layer by chlorofluorocarbons (CFCs) which were used as a propellant . Many other air freshener delivery methods have become popular since, including under the seat wafer air fresheners, scented candles, reed diffusers , potpourri , and heat release products. Air fresheners introduce fragrance into

2412-584: The Bureau Européen des Unions de Consommateurs ( BEUC ) found that many air freshener products emit allergens and toxic air pollutants including benzene , formaldehyde , terpenes , styrene , phthalate esters , and toluene . In the United States, since 2020 air fresheners (as well as cleaning solutions and products used to clean cars) have been required to list any of their ingredients which are on California's list of 2,300 harmful chemicals, based on

2479-466: The Weber-Fechner law: I = a × log(c) + b, where I is the perceived psychological intensity at the dilution step on the butanol scale, a is the Weber-Fechner coefficient, C is the chemical concentrations, and b is the intercept constant (0.5 by definition). Odor intensity can be expressed using an odor intensity scale, which is a verbal description of an odor sensation to which a numerical value

2546-539: The air of interior spaces either as droplets which transition to vapor, or as the molecules of fragrance ingredients directly evaporating from a source. Fragrance diffuses into the air to mask other odors or to introduce a specific odor. Mechanisms for the control of indoor airborne odors can be grouped into various different classes: Delivery of the above air freshener mechanisms falls into two broad categories: continuous action and instant action. Continuous action products include scented candles and devices which use

2613-458: The ambient air. These two contexts require different approaches for measuring odor. The collection of odor samples is more easily accomplished for a source emission than for odor in the ambient air. Field measurement with portable field olfactometers can seem more effective, but olfactometer use is not regulated in Europe, while it is popular in the U.S. and Canada, where several states set limits at

2680-401: The back of the nasal cavity . There are millions of olfactory receptor neurons that act as sensory signaling cells. Each neuron has cilia in direct contact with the air. Odorous molecules bind to receptor proteins extending from cilia and act as a chemical stimulus, initiating electric signals that travel along the olfactory nerve's axons to the brain. When an electrical signal reaches

2747-549: The binding of many odorant molecules. In 1978, Crabtree suggested that Cu(I) is "the most likely candidate for a metallo-receptor site in olfaction" of strong-smelling volatiles. These are also good metal-coordinating ligands, such as thiols. In 2012, Zhuang, Matsunami, and Block confirmed the Crabtree/Suslick proposal for the specific case of a mouse OR, MOR244-3, showing that copper is essential for detection of certain thiols and other sulfur-containing compounds. Thus, by using

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2814-443: The central nervous system (CNS), which controls emotions and behavior as well as basic thought processes. Odor sensation usually depends on the concentration (number of molecules) available to the olfactory receptors. A single odorant is usually recognized by many receptors. Different odorants are recognized by combinations of receptors. The patterns of neuron signals help to identify the smell. The olfactory system does not interpret

2881-526: The chemical interactions of ingredients with other substances, allergy-provoking ingredients, misuse, and accidental injury. Many air fresheners employ carcinogens , volatile organic compounds and known toxins such as phthalate esters in their formulas. A Natural Resources Defense Council (NRDC) study of 13 common household air fresheners found that most of the surveyed products contain chemicals that can aggravate asthma and affect reproductive development. The NRDC called for more rigorous supervision of

2948-407: The concentration C may be exceeded based on the averaging period. There are two main odor sampling techniques: direct and indirect odor sampling techniques. Direct refers to the placement of an enclosure on or over an emitting surface from which samples are collected, and an odor emission rate is determined. The most commonly used direct methods include the flux chamber and wind tunnels such as

3015-814: The dislike for a particular environment. It is important to set occupational exposure limits (OELs) to ensure the health and safety of workers, as well as comfort, because exposure to chemicals can elicit physiological and biochemical changes in the upper respiratory system. Standards are hard to set when exposures are not reported and can also be hard to measure. Workforce populations vary in terms of discomfort from odors because of exposure history or habituation, and they may not realize possible risks of exposure to chemicals that produce specific odors. Some odors are sought after, such as from perfumes and flowers, some of which command high prices. Whole industries have developed around products that remove or mask unpleasant odors, such as deodorant . Odor molecules transmit messages to

3082-487: The effectiveness of aromatherapy is mostly anecdotal and controlled scientific studies to substantiate its claims are lacking. Some people are allergic to the fragrances found in perfume, scented shampoo, scented deodorant, or similar products. Reactions, as with other chemical allergies, can range from slight headaches to anaphylactic shock , which can result in death. Unpleasant odors play various roles in nature, often to warn of danger, though this may not be known to

3149-448: The following, which identifies 7 primary odors: Though the concept of primary odors is not universally accepted. In many countries odor modeling is used to determine the extent of an impact from an odor source. These are a function of modeled concentration, averaging time (over what time period the model steps are run over, typically hourly), and a percentile. Percentiles refer to a statistical representation of how many hours per year

3216-495: The home was found to correlate with increased earaches and diarrhea in infants, and with increased depression and headaches in their mothers. In 2008, Anne C. Steinemann of the University of Washington published a study of top-selling air fresheners and laundry products. She found that all products tested gave off chemicals regulated as toxic or hazardous under federal laws, including carcinogens with no safe exposure level, but none of these chemicals were listed on any of

3283-511: The judgment of the air-assay happens without diluting the samples. Odor measurement is essential for odor regulation and control. An odor emission often consists of a complex mixture of many odorous compounds. Analytical monitoring of individual chemical compounds present in such an odor is usually not practical. As a result, odor sensory methods, instead of instrumental methods, are normally used to measure such odor. Odor sensory methods are available to monitor odor both from source emissions and in

3350-510: The late 1800s which coincided with the arrival of the first synthetically produced fragrances. However, air freshening consumer products first gained wider popularity in the 1940s. In 1939, Air Wick launched in the United States, initially producing liquid air fresheners in a variety of fragrances, which worked by evaporation with the help of a wick. The products claimed to kill odors, not just mask them, by using chlorophyll . As early as 1953, scientists were questioning whether chlorophyll, at

3417-478: The manufacturers and their products, which are widely assumed to be safe: The study assessed scented sprays, gels, and plug-in air fresheners. Independent lab testing confirmed the presence of phthalates , or hormone-disrupting chemicals that may pose a particular health risk to babies and young children, in 12 of the 14 products—including those marked 'all natural.' None of the products had these chemicals listed on their labels. On September 19, 2007, along with

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3484-739: The olfactory mucosa through the oral cavity often as food) was partially responsible for the development of human olfactory acuity. He suggested the evolutionary pressure of diversification of food sources and increased complexity of food preparation presented humans with a broader range of odorants, ultimately leading to a "richer repertoire of smells". Animals such as dogs show a greater sensitivity to odors than humans, especially in studies using short-chain compounds. Higher cognitive brain mechanisms and more olfactory brain regions enable humans to discriminate odors better than other mammals despite fewer olfactory receptor genes. Odor concentration refers to an odor's pervasiveness. To measure odor sensation, an odor

3551-433: The one at the University of New South Wales (UNSW). There are many other available techniques, and consideration should be given to a number of factors before selecting a suitable method. A source which has implications for this method are sources, such as bark bed biofilters , that have a vertical velocity component. For such sources, consideration must be given as to the most appropriate method. A commonly used technique

3618-733: The outdoor environment, leading to greater potential for toxic health exposures from a variety of chemical compounds. Health effects of odor are traced to the sensation of an odor or the odorant itself. Health effects and symptoms vary—including eye, nose, or throat irritation, cough, chest tightness, drowsiness, and mood change—all of which decrease as an odor ceases. Odors may also trigger illnesses such as asthma, depression, stress-induced illness, or hypersensitivity. The ability to perform tasks may decrease, and other social/behavioral changes may occur. Occupants should expect remediation from disturbing and unexpected odors that disturb concentration, diminish productivity, evoke symptoms, and generally increase

3685-409: The physical, the gas chromatographical , and the chemosensory method. When measuring odor, there is a difference between emission and immission measurements. Emission measurement can be taken by olfactometry using an olfactometer to dilute the odor sample. Olfactometry is rarely used for immission measurement because of low odor concentrations involved. The same measuring principles are used, but

3752-579: The product labels or material safety data sheets . Chemicals included acetone , the active ingredient in paint thinner and nail-polish remover; chloromethane , a neurotoxicant and respiratory toxicant; and acetaldehyde and 1,4-dioxane , both carcinogens. A plug-in air freshener contained more than 20 different volatile organic compounds, with more than one-third classified as toxic or hazardous under federal laws. Even air fresheners called "organic," "green," or with "essential oils" emitted hazardous chemicals, including carcinogens. A report issued in 2005 by

3819-467: The product or the growth of microorganisms in it. These can include: These are substances that help other ingredients mix together, either by dissolving or emulsifying. Solvents used in air fresheners include ethanol , mineral oil , or glycol ethers such as 2-butoxyethanol and trideceth-4 . There have been various concerns about air fresheners having adverse health effects, due to factors including harmful ingredients, secondary substances formed by

3886-417: The receptor sites or along the perimeter of odor-emitting plants, expressed in units of dilution-to-threshold (D/T). Odor intensity is the perceived strength of odor sensation. This intensity property is used to locate the source of odors and perhaps most directly related to odor nuisance. The perceived strength of the odor sensation is measured in conjunction with odor concentration. This can be modeled by

3953-433: The removal of toxic substances from the air in building interiors. Odors An odor ( American English ) or odour ( Commonwealth English ; see spelling differences ) is a smell or a scent caused by one or more volatilized chemical compounds generally found in low concentrations that humans and many animals can perceive via their olfactory system . While smell can refer to pleasant and unpleasant odors,

4020-514: The second decade of life, and then deteriorating appreciably as age increases, especially once over 70 years of age. For most untrained individuals, the act of smelling acquires little information concerning the specific ingredients of an odor. Their smell perception primarily offers information that elicits an emotional response. Experienced individuals, however, such as flavorists and perfumers , can identify discrete chemicals in complex mixtures using only their sense of smell. Odor perception

4087-417: The sense of smell. The human sense of smell is comparable with many animals, able to distinguish between a diverse range of odors. Studies have reported that humans can distinguish in the region of one trillion unique aromas. Odors that a person is used to, such as their own body odor , are less noticeable than uncommon odors. This is due to "habituation." After continuous odor exposure, the sense of smell

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4154-451: The source of an unpleasant odor will decrease the chance that people will smell it. Ventilation is also important to maintaining indoor air quality and can aid in eliminating unpleasant odors. Simple cleaners such as white vinegar and baking soda , as well as natural adsorbents like activated charcoal and zeolite , are effective at removing odors. Other solutions are adapted to different types of odor. Some house plants may also aid in

4221-404: The spray nozzle located inside the actuator to create a mist of droplets containing fragrance. These droplets are 30 to 50 micrometres in diameter. A recently developed alternative, the "bag-on-valve" aerosol, places the air freshener inside a bag in the can. The can is filled with pressurised air which squeezes the bag and pushes out the product when the actuator is pressed. An atomizer operates in

4288-458: The strength of the odor (intensity) and the pleasantness of an odor (hedonic tone). The perception of an odor may change from pleasant to unpleasant with increasing concentration, intensity, time, frequency, or previous experience with a specific odor—all factors in determining a response. The overall set of qualities are sometimes identified as the "FIDOL (Frequency, Intensity, Duration, Offensiveness, Location) factors". The character of an odor

4355-412: The terms scent , aroma , and fragrance are usually reserved for pleasant-smelling odors and are frequently used in the food and cosmetic industry to describe floral scents or to refer to perfumes . The perception of odors, or sense of smell, is mediated by the olfactory nerve . The olfactory receptor (OR) cells are neurons present in the olfactory epithelium , which is a small patch of tissue at

4422-448: The time popular as a body deodorizer or for use on wounds, really acted as a space deodorizer. From 1947 to 1951, the company sold 7 million dollars' worth of these and other types of air fresheners. The first fan-operated air freshener product was invented in 1946 and released by the company Surco under the brand Air-Scent in 1948. In the United States, commercial aerosol sprays were introduced in 1948, based on what had been

4489-469: The use of organic and everyday household items. Fragrances have been used to mask odors since antiquity. A variety of methods and compounds have been used over the past two millennia for their abilities to create pleasant aromas or eliminate unpleasant odors in indoor spaces. These were often linked with spiritual or religious practices (e.g. the use of incense ), or with concepts of health and hygiene. Consumer products for air freshening began to emerge in

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