Sheri Gwinn, age 12, of Whitesville, W.Va., for her question:
HOW DO AEROSOL SPRAYS AFFECT THE OZONE?
A number of chemicals called fluorocarbons, or chlorofluorocarbons, are used as propellants in more than half of the aerosols that are manufactured today. Other chemicals included are hydrocarbons and nitrous oxide. In addition, there is carbon dioxide in a compressed gas form that is used in almost all aerosol cans.
At the start of the 1970s a major controversy started over the safety of aerosol containers that used fluorocarbons, also known as freons. Near the earth's surface, a large number of scientists reported, flourcarbons do not react with other chemicals. Instead, the fluorocarbons rise to the upper regions of the atmosphere and there extremely powerful radiation from the sun causes them to break up and release chlorine atoms.
Many scientists believe that the chlorine atoms react chemically and diminish the layer of ozone of the atmosphere. The ozone layer protects the earth's surface from dangerous ultraviolet radiation from the sun, so it is important that it remain together.
To avoid the threat of a possible destruction of our ozone layer, many leading scientists and environmentalists have called for laws that will restrict the use of fluorocarbons.
At the present time, many product manufacturers are curtailing the number of aerosol products they produce that contain elements that may be harmful.
Aerosol cans, however, serve a number of very useful purpose in many areas, and not all of them contain possibly harmful fluorocarbons. Many foam products that are packaged in high pressure cans are also called aerosols. Included in this type of product you'll find whipped cream and shaving cream. Fine particles are not produced from this type of can or with items in this product line.
Many natural aerosols result from chemical reactions of gases. These reactions form liquid or solid particles. In most manufactured aerosols, the item to be sprayed is mixed with a propellant which often is a liquefied gas at high pressure in the container. When the solution sprays from the container's nozzle, the propellant vaporizes and the particles are then shot into the air.
Aerosol particles are usually so small that they remain in the air for a long time before gravity finally makes them settle. For this reason, room deodorizers and disinfectants are extremely effective in aerosol form. And now the manufacturer has a new objective: produce these products in such a way that no harm will come to our environment.