In California, they are called the Santa Ana winds. The Indians in Arizona call them the "Bitter Winds." In Canada, they are the Chinook; in Israel, the Sharav.

Even in biblical times, people knew that they were "ill winds," hot, oppressive winds that made life miserable and set tempers on edge. But only in recent years have scientists begun to discover why the winds are so physically and psychologically unfriendly for humans.

The cause is an imbalance in the electrical charges in the air. "Normal" air contains a balance of positive and negative electrical charges. Winds such as the Sharav and the Santa Ana contain high amounts of positive ions -- electrically charged atoms or groups of atoms.

Positive ions have been linked to a number of physical and psychological problems. Conversely, negative ions, believed by some to be an invisible boon to man, can clean odors, dust and pollution from the air, promote plant growth, help asthma and allergy sufferers, and improve cranky dispositions.

The Soviets have done extensive research into the use of negative ion-producing generators for increasing the efficiency of workers. Both the Soviets and the Israelis are experimenting with the use of the generators for athlete training. Other studies have shown that the generators can speed recovery from burns.

The best-selling ion generator in the United States in FreshenAire, distributed by USI Trade Corp. of Northbrook, Ill. In addition to the models sold for home use, they have also developed a model for the auto, which helps to cut down on driving fatigue and exhaust pollution, said a company spokesman.

"The product is going great guns now," the spokesman said. "It also has been a huge success in Canada."

The generators, produced by Amcor Ltd., Israel's largest electronics company, were only recently introduced to the United States but have been widely used for years in Europe.

"They have proven to be particularly good for people with allergies and respiratory problems," explained Anita Oakes, senior executive for Paradise Marketing of Three Rivers, Mich., which distributes the; Home-Ions-from Paradise models. "Someone with and allergy will notice that they are breathing more easily within minutes."

By changing the magnetic charge of the air, the generators cause dust, pollen, spores and other indoor air pollution to cluster and drop to the floor. p

"But do you want the dust in your lungs or on your carpet?" Oaks said.

Older homes and buildings tend to be draftier, but they also provide more frequent flow of balanced air from the outside. Modern homes and offices tend to seal in and recirculate the air and the positive ions.

Synthetic drapes, carpets and clothing all can be sources of positive ions. Air conditioners and forced-air heating and cooling systems generate positive ions, which can lead to increased irritability and a decrease in productivity, she said.

"The positive ions tend to concentrate during the day," she said. "And you become more irritable, so you bite the guy's head off at the desk next to you. By the end of the day you don't feel that good. Then you get up and go outside, where the air is better. After you're outside for about 10 minutes you don't feel so bad."

But the machines do have their detractors. Dr. Alfred Zamm, author of "Why Your House May Endanger Your Health" and an expert on "indoor pollution," cautions that the machines do not benefit everyone.

"I have tried all kinds of ion generators personally and they do not have any effects on me," Zamm said. "I suspect that those people who do experience changes are very sensitive to pollutants. For them it's possible it could help."