Aerosol

A aerosol is a particle, solid or liquid, in suspension in a medium Gaz them. Emitted by the human activities or natural, the aerosols intervene with planetary scales and local in the phenomena of Air pollution.

In the everyday life, the term “aerosol” indicates the container containing a product and a propellent gas. The engine creates a pressure inside the container. By opening the valve of exit, one expels the mixture. The product is pulverized in the form of aerosol, i.e. in fine suspended particles in the air.

The aerosol in the everyday life

History

The aerosol was invented by German Schmauss in 1920. In 1929, a Norwegian inventor, Erik Rotheim made patent the use of a pressure vessel provided with a valve for the diffusion with a large variety with products.

This principle is applied in 1941 with the first Insecticide in aerosol.

Propellent gases

Until the years 1980, the aerosols released from CFC (Chlorofluorocarbone S). CFC were used as propellent Gaz since the Second world war because of their interesting properties: they are non flammable, odorless and stable. CFC destroy the Couche of ozone. They are now prohibited in Europe and North America.

The freon was used for foams to shave and deodorizers.

Various propellent gases are used, which do not have an effect on the layer of ozone. The Propane, the Butane and the Isobutane are flammable and explosive hydrocarbons. The Azote (main component of the Air) is an inert propellent gas thus less dangerous. The Carbon dioxide is sometimes used as propellent gas.

The nitrogen protoxide has the same thermodynamic characteristics as carbonic gas. It is more expensive, but is much less corrosive for the case when the active product contains water.

The dimethyl ether is an engine liquefied flammable, but soluble with water, which makes it possible to obtain aerosols with the reduced danger of inflammability. It has a very good capacity solvent, which allows its use in the aerosols of painting.

The 134 (Tétrafluoro ethane) is a non flammable fluorinated hydrogéno. Its molecule does not contain chlorine. It does not have an action on the layer of ozone, but with a large greenhouse effect. One speaks to prohibit it or to limit the use of it, although it is the last non flammable engine still authorized. It is rather expensive, which limits its use.

One never should pulverize an aerosol on a flame or a hot spot (hotplate, thermal engine…) because of the immediate ignition and risk of explosion.

Manufacture

An aerosol appears as a container Métal lic under pressure with a propellent stopper in plastic. The container is often in Acier or Aluminum. Out of steel, it will be produced by rolling then welding of the body with setting of the ends. Out of aluminum, it will be spun (violent shock of a punch on a thick pastille) then equipped with a head by setting. For the convenience of use, a plastic stopper injected will generally protect the valve. This one is a precise mechanism composed of several very precise and reliable parts in spite of their realization in very great series and their automated assembly.

The process in synthesized images is visible while following the following bond: Process

Waste

The Déchet S of an aerosol (quantity of Packing and propellent gas) are important compared to the quantity of product which it contains. Even if metal is Recyclable, the aerosols are not always accepted in Recycling. Indeed, if they are not completely empty, they can be dangerous because of residual gas, especially if they contained toxic products.

In all the cases, it should be remembered that an aerosol contains gas under pressure. It should neither be exposed with heat nor left in full sun because even tiny, the risk of explosion exists (the flammable gas normally not being mixed with dioxygene of the air) the dilation of gas can also exceed the resistance of the valve. For the same reasons, one should not throw to fire the empty aerosols.

Volatile organic compounds

The aerosols emit particles of small size which are easily inhaled. The aerosols can emit, according to the composition of the products contained, the volatile Composés organics (COV). The emitted COV include/understand for example hydrocarbons.

The volatile organic compounds are pollutants which have a harmful effect for health. They take part in the interior Pollution of the dwellings. Combined with nitrogen oxides, certain COV can form Ozone, which is polluting with lower atmosphere.

Various types of aerosols

See too

External bonds

  • BOU KARAM Diana: Scientist specialized in the radiative impact study of the desert aerosols on the climate, Publications, conferences and current events of research

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