There's good ozone and bad ozone, and air conditioning produces the bad kind


You probably have heard of ozone, the Dr. Jekyll and Mr. Hyde of chemicals. It is an odd form of oxygen, a gas that normally floats around as O2. Ozone is O3, and it occurs naturally in a gaseous layer in the stratosphere, seven miles above the Earth.

This high layer of ozone acts as a selective shield around the Earth. It absorbs intense ultraviolet radiation from the sun that would otherwise make life here difficult, if not downright nasty.

Ozone is also found in the lower atmosphere, where it is created when certain byproducts of combustion react with sunlight. Ground ozone is a major pollutant. It contributes to smog, damages crops and forests and is dangerous to human health.

This is a rare case where we have the perfect repository for a pollutant. But, unfortunately, it isn't possible to vacuum up ground ozone and move it to the stratospheric ozone layer. This is doubly unfortunate because we could really use it up there.

Certain chemical compounds called chlorofluorocarbons, or CFCs, are drifting up to the ozone layer and destroying it. This is causing a measurable increase in ultraviolet radiation down on Earth. Scientists expect there will be a consequent increase in skin cancer and cataracts in humans and a variety of nasty problems in other animals and plants.

Where are the CFCs coming from? We manufacture them. We use them as a coolant -- Freon -- in refrigerators and air conditioners, and for blow-in insulation. We use them to clean electronics and we use them in making polystyrene rigid insulation.

Can we live without CFCs? Manufacturers are experimenting with alternatives, and CFCs have long been banned for use as propellants in aerosols. By international agreement, CFC production is being phased out over the next few years. In the meantime, there is quite a lot we can each do to lessen our contribution to the problem -- before we all have to swathe ourselves from head to toe and wear dark glasses whenever we leave the house.

Coolant CFCs may be the ones you can do most about. That's because about 100 million American cars use CFCs in their air conditioners. Each of those units springs a leak every three years, on average. When that happens, mechanics routinely vent the remaining CFCs before they repair the leak. A mechanic will often use a whole batch of CFCs just to flush the system before refilling it, releasing pure CFCs into the air.

The best advice for someone concerned about ozone depletion is: Don't buy a car with air conditioning. They're guaranteed to leak.

An air conditioner isn't the only device that can keep your car cool. There is the barrier approach -- those folding cardboard shades you can prop on your windshield whenever you park in a sunny spot. Or you can go for something a little more high tech -- one of those fans that clips onto your --board and plugs into the car's cigarette lighter, for example.

If you can't live without air conditioning in your car, don't feel too bad. Two years ago, Underwriter's Laboratory approved a CFC recycling machine that sucks coolant out of a leaking unit and purifies it for reuse. Because of the rising cost of CFCs, more and more service stations and dealers are buying these machines. If you suspect your car has a leaky a/c, don't delay. Call around to find a mechanic that can recycle CFCs and take your car in right away.

However tempting, never buy a 14-ounce can of CFCs at an auto parts store to pump up a failing air conditioner. The quick fix that restores your unit lasts a very short time and releases CFCs into the atmosphere that last 150 years. Until you repair the leak, don't pour more CFCs into the system.

If you own a car with a functioning air conditioner, should you stop using it? Emphatically not. Car units are so leaky because of sealing problems and the harsh conditions under the hood. The coolant contains oils that keep the seals soft and functional. When you stop using the air conditioner, the oil doesn't circulate onto the seals, they dry out, and soon you've got a leaky air conditioner. Be sure to run your a/c for at least 10 minutes a month, even in winter.

And save your money. Buy a new car in 1994. By then manufacturers hope to be selling cars with a groovy alternative coolant so you can buy a new model, keep cool and ride guilt free -- though, of course, you'll still need to feel guilty about air pollution, global warming, fuel shortages, destruction of habitat and the like. But, hey, one step at a time.

(Feeling environmentally incorrect? Write a letter to Ms. Household Environmentalist -- on recycled, unbleached paper, of course, using soy-based ink -- and send it to P.O. Box 121, 1463 E. Republican St., Seattle, Wash. 98112.)

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