Pssssssst! Used any aerosols lately? You know. Those point-and-shoot cans with the little button on top. Press down, and tiny droplets of something or other rocket out to coat your target -- whether it's your underarm, your bicycle chain or the collar of the shirt you are ironing.
If you have used aerosols, you may have noticed a warning label on the can: Contents under pressure. Do not puncture or incinerate. The warning refers to the gases inside that are responsible for delivering the active ingredient -- antiperspirant, lubricating oil, starch or whatever. Because these gases are greatly compressed, an aerosol can may explode if punctured or burned.
An exploding can of antiperspirant sounds pretty deadly. But the warning is incomplete. Aerosol cans are also a mostly avoidable source of air pollution.
The pollution in aerosols comes from the propellant, the compressed gases that deliver the goods. Two families of chemical compounds are generally used for this purpose: chlorinated compounds called chlorofluorocarbons (CFCs) and volatile organic compounds called hydrocarbons (HCs). Carbon dioxide is also used in a small percentage of aerosols, but because it can't deliver as fine a mist as CFCs and HCs can, this gas isn't as useful.
CFCs are an old story. These chemical compounds don't exist in nature. They were developed in a laboratory and are produced in chemical plants. Released into the air, they slowly drift into the upper atmosphere. There they break down, releasing chlorine atoms that change the chemical makeup of the ozone layer. This naturally occurring layer of gas shields the Earth from much of the sun's most harmful rays. As the ozone thins, more radiation reaches the Earth, a process that already is causing a huge increase in skin cancer in humans and lower productivity in plants.
The United States, Canada and Western Europe banned CFCs for most aerosol uses more than a decade ago. Many other countries will soon be following suit. But aerosols still account for about 35 percent of CFCs worldwide, and even in countries that regulate CFCs, some aerosol manufacturers are still allowed to use them.
When aerosol makers shopped around for an alternative to CFCs, they looked to hydrocarbons -- butane, isobutane, propane and others -- to squirt their products. Unfortunately, environmentally speaking, these compounds stink, too.
The trouble with hydrocarbons is that, in the presence of sunlight, they react with pollutants called oxides of nitrogen to produce -- are you ready? -- ozone. And while we desperately need the stuff seven miles up, ozone in the lower atmosphere is a major ingredient of the dangerous chemical soup we call smog. In fact, hydrocarbons are one of the principal air pollutants that come out of your car's tailpipe.
Just how much pollution can those little cans account for? According to the California Air Resources Board, a single can of antiperspirant releases as many hydrocarbons as does a new car on an 800-mile drive.
National figures for hydrocarbon emissions from consumer aerosol products other than paint are not available. But Southern California, which has horrendous air pollution problems, has published some findings: In Los Angeles alone, aerosol deodorant and antiperspirant users spray 3.5 tons of hydrocarbons into the air daily. Statewide, Californians spray 27 tons of hydrocarbons from hair spray into the air every day. California has passed regulations requiring manufacturers to cut smog-forming hydrocarbons in aerosols by 60 percent by 1995.
Fortunately, few parts of the country have Southern California's air pollution problems. But you don't have to live in California to care about air quality.
Take an inventory of your own household's aerosol use. Check in the garage and laundry room, under the kitchen sink, in your medicine cabinet and on your dresser. Look for: lubricating oil, spray paint, dust remover, spray starch, furniture polish, air deodorizer, shaving cream, deodorant, hair spray, etc.
Next time you empty an aerosol can, consider switching to a different delivery system. Many products are available in other forms. However, many of the products themselves contain hydrocarbons as a solvent -- something that keeps them wet in the tube, but dries in the air. This is true of styling gels, for example. Cultivate the natural look. In the case of deodorants and antiperspirants, aerosols do contain significantly more HCs than alternative products.
Manufacturers will soon be developing aerosols with much lower hydrocarbon content to conform to the new California regulations. In the meantime, switching to a roll-on is a small price to pay for a little less air pollution.