Recently aerosol products have been widely charged with damaging the ozone layer. They have also been equated with automobiles and smokestacks in terms of smog potential. None of these claims is true, yet many
Americans, rightfully concerned about the environment, perceive aerosols as a threat to clean air.
Much of the confusion is due to outdated and misunderstood data. This information, prepared for teachers, editors and
other thought-leaders, attempts to shed some light on an emotional subject; to separate fact from fiction and to position aerosols in their proper place vis-à-vis today’s environment.
Q. What are aerosols, anyway?
A. Aerosols are very fine particles of liquid or solid substances suspended in air. Fog, for example, is a natural aerosol. In aerosol packaging, the substance
to be sprayed is propelled through a valve as a fine mist or foam. This provides a safe, efficient means of dispensing thousands, of consumer products such as shaving cream, hair spray, paint and anti-perspirants.
Q. How long have aerosols been around?
A. Fifty years ago, U.S. Department of Agriculture scientists developed the principle of pressurized insect spray. This gave birth to the container used by
American troops to fight malaria in the South Pacific during World War II.
Today’s lightweight, low-pressure can is a direct descendent of the ponderous, high-pressure canister. Refinements to containers, valves
propellants and formulas have broadened the range of aerosol products and widened consumer acceptance. Aerosol related jobs now employ over 50,000 Americans.
Q. What is the ozone layer?
A. In the stratosphere, some 12 to 20 miles above the earth, ozone (an unstable and very reactive from of oxygen) forms a protective layer that blocks most of the sun’s ultra-violet
rays.
Q. What causes ozone depletion?
A. In addition to natural phenomena, such as earthquakes, among the man-made products believed to contribute to ozone damage are chlorofluorocarbons, used mainly in refrigerators and
air-conditioners.
Q. Do aerosols contain chlorofluorocarbons?
A. Since 1978 no aerosols made or sold in the U.S. have contained CFC’s, except for a tiny fraction (less than 2%) specifically approved by the government for essential
medical and other unique uses, such as inhalers for asthma suffers.
Not only are CFCs absent from the propellants used in aerosols, but there are none in the products packed in the cans either, such as hair spray,
deodorants, anti-perspirants or other personal care items, nor in spray paint, household, food or automotive products.
The industry is in full compliance with rules established by the EPA, the FDA and the Consumer Product
Safety Commission.
Q. Then why the confusion?
A. Aerosol Manufacturers in Europe and other parts of the world did not follow the lead of U.S. industry in substituting alternate propellants for CFCs. The fact that aerosol made
overseas still contain CFCs has caused confusion in press reports and in the public mind about the ozone-aerosol link. However, American consumers can be confident that aerosols made in the U.S. will not damage the ozone
layer.
Q. What about the problem of urban smog?
A. As urban areas struggle to meet federal air quality standards, regulators are attempting to identify any products that emit volatile organic compounds (VOCs) which in turn
contribute to lower level ozone. Unlike upper level or stratospheric ozone, which protects us, this lower level or tropospheric ozone is a major component of smog.
The smog problem is particularly acute in California,
and that state has identified a variety of consumer products which emit VOCs as among those sources which may be regulated once studies have been completed.
Q. So aerosols do contain VOCs?
A. Yes, but so do fingernail polish, perfume and mouth wash, as well as pump hair sprays, roll-ons and stick deodorants. Restrictions on these products are hardly the answer
to air pollution. The solution to the smog problem, for example, lies on the freeways and in the power plants, not in the medicine cabinet or the bedroom.
Q. What propellants are used in aerosol cans today?
A. Depending on the end use, either liquefied or compressed gases are used to dispense the product from the aerosol container in the most efficient manner.
Neither type is a chlorofluorocarbon.
Liquefied propellants, such as isobutane, butane and propane, are natural, organic products, which do not deplete the ozone layer, taint the soil or pollute the water supply. As
used in aerosol cans, their contribution to lower level ozone formation is negligible.
Compressed gas, such as carbon dioxide (the same gas, which puts the “fizz” in soda pop) is used in products designed to deliver a
coarse spray at close range; in household disinfectants, for example.
Nitrogen, as used in contact lens cleaners, and nitrous oxide as used in whipped toppings are also used as propellants.
Q. If the contribution of aerosols to air pollution is minimal, then why are they suspect?
A. Aerosols, still remembered from the pre-1978 chlorofluorocarbon/ozone controversy, offer a convenient target. Perhaps
because of their “high-tech” characteristics, they don’t seem to fit the profile of a “natural” product.
Rather than switching to non-aerosol containers, well-meaning consumers who are concerned about air quality
would be far better advised to simply to maintain the family car according to the owner’s manual.
Q. But aren’t alternative packages better for the environment?
A. Once again, myth prevails over reality. For example, pump sprays are generally perceived as being environmentally superior. Actually, the
ingredients in the pump container, which replaces the aerosol propellant, contain as many if not more VOCs than the aerosol can.
Q. But after all, do we really need aerosols?
A. The aerosol container is a unique package. It is convenient, effective and efficient. It offers consumers a controlled, “clean-hands” way to deliver
personal care, spray paint, household and automotive products. It is hermetically sealed and its contents are always free of bacterial contamination.
It would be tragic indeed if aerosol were to be replaced with
less-effective alternatives, with absolutely no resulting improvement in air quality.
Before you left home this morning, you probably reached for an aerosol container to apply shaving cream or hair spray. When you get home this evening, you may use a low-cholesterol cooking spray or an aerosol-cleaning product. Americans now use more than 1,500 different kinds of aerosol products at home and at work.
The aerosol container is a sophisticated, high-technology package in which a product household cleaners, disinfectant, deodorant, insect repellant, paint and hundreds of others is dispensed under pressure to create a spray or foam. The aerosol package is designed to let you buy what you need, store it for use when you need it, and apply it quickly and cleanly. And, like so many things that have become a part of our everyday lives, it’s easy to take for granted.
Myths and misperceptions
According to a 1991 Roper poll commissioned by S.C. Johnson & Son, a majority of Americans about 86 percent think that the aerosol industry is allowed to use chlorofluorocarbon (CFC) propellants in its products. The truth is, aerosol manufacturers in the United States are not allowed to use, and don’t use, CFC propellants.
The aerosol industry began phasing out CFCs in the mid-1970s. In 1978, the U.S. Environmental Protection Agency issued regulations prohibiting the use of CFC propellants. Several other countries have banned CFC us as well, including Canada, Great Britain, Australia, and Mexico. Today, more than 99 percent of the consumer aerosol products produced in this country do not contain CFC propellants. The few that do less than 1 percent, mostly asthma inhalers and some medications do so with government approval.
How an aerosol works
The aerosol package is a self-contained dispensing system with three main elements:
- The product is a blend of active ingredients, like soap or disinfectant; inert (or inactive) ingredients, like water; and propellants.
- The propellantis a gaseous compound, which pushes the product out of the container and produces a spray or foam. In most cases, the propellant also acts as a solvent to keep the product at the proper strength. In the United States, the most common propellants are naturally occurring hydrocarbons. A few products, about 10 percent of today’s aerosols, use compressed gases like carbon dioxide and nitrous oxide as propellants.
- The final element is the container, which is usually a steel or aluminum can. The leak-proof can protects the product from contamination and evaporation.
All of these pieces work together based on simple scientific principles. An aerosol package is an air tight, pressurized container. Pressing the actuator button opens the valve. Since the pressure outside the can is less than the pressure inside, the propellant expands, pushing the product up the dip tube and out through the valve. This system allows the product to be applied in a variety of ways: in a fine mist, a metered spray delivering just the right amount, a foam, or even a long-distance spray.
Safety and disposal
Like most household or personal care products, aerosols are not hazardous when handled and disposed of properly. Reading and following the instructions printed on the label will ensure proper and safe use. The label instructions are there for your protection.
The best way to dispose of an empty aerosol container is to recycle it. Most aerosol cans are made of steel, and can be recycled like any other empty steel cans. A growing number of communities accept empty aerosol cans together with other metal containers; check with your local recycling coordinator, however, before putting any material in your recycling bin. Be sure to use the product up, and then put the container in the trash with your other solid waste if recycling is not available.
Aerosols work for you
Fifty years ago during World War II, scientists at the U.S. Department of Agriculture created the first aerosol spray to protect soldiers in the South Pacific from disease-carrying insects. Those backpack canisters were large and hard to handle, but the spray was effective. Today, thanks to improved technology, light-weight, low-pressure sprays can be found in hundreds of different sizes and shapes. From purse-sized breath atomizers to family-sized bathroom cleaners, aerosol products can be found in almost every home and workplace, providing products that improve our health, comfort and quality of life.
Because they are effective and easy to use, aerosol products are something we all take for granted. But that’s the way it should be¾aerosols are designed to be a part of our everyday lives.