Air fresheners are consumer products used in homes, or commercial products used in restrooms, that typically emit fragrance. There are many different methods and brands of air freshener. Some of the different types of air fresheners include sprays, candles, oils, gels, beads, and plug-ins. There are also solid and passive versions, which use ceramic material and water based ingredients - these combine and create a’multi-phasing’ effect which provides a constantly evolving fragrance. Some air fresheners have been known to have chemicals that provoke allergy and asthma symptoms raising argument about how safe it is to use. However, some air fresheners are VOC exempt, such as a passive, multi-phasing air freshener, that reduces the effects. Air freshening is not only limited to modern day sprays, air freshening also can involve the use of organic and everyday house hold items. Although air freshener is primarily used for odor elimination some people simply use air freshener for the pleasant odors they emit.
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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 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 a vapor in a cold process without the use of heat.
Instant action systems are mainly aerosol sprays, or atomizers. The aerosol spray uses a propellant and fragrance packaged under pressure in a sealed metal or glass 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 the spray nozzle located inside the actuator to create a mist of droplets containing fragrance. These droplets are 30 to 50 micrometres in diameter. The atomizer is a glass, metal or plastic container of fragrance which operates in 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. The mist created contains droplets 50 to 150 micrometres in diameter. A recently developed type of aerosol packages a plastic bag of fragrance into a can. The bag is attached to the valve/actuator/spray nozzle and sealed in the can surrounded by air under pressure. When the actuator is pressed, the valve opens and the liquid forced through the nozzle by the pressure around the bag