THE AIR CONTAINS POSITIVELY CHARGED IONS (POSIONS) AND NEGATIVELY CHARGED IONS (NEGIONS). BOTH ARE ABUNDANT IN NATURE, BUT ARTIFICIAL ENVIRONMENTS ALTER THE NATURAL IONIC BALANCE. WHEN THE TOTAL IONIC CONCENTRATION IS REDUCED BY MORE THAN 80 PERCENT (ION DEPLETION), ORGANISMS BEGIN TO SLOW DOWN. WHEN THE RATIO OF POSIONS TO NEGIONS EXCEEDS THREE TO ONE (POSION TOXICITY), 'PRESTORM' SYMPTOMS--FATIGUE, HEADACHE, IRRITABILITY, HIGH PULSE RATE AND BLOOD PRESSURE--BEGIN TO APPEAR. IN MANY AIR-CONDITIONED, WINDOWLESS WORKING ENVIRONMENTS, THE TOTAL ION CONCENTRATION IS LESS THAN 10 PERCENT OF NORMAL. ION DEPLETION AND IMBALANCE CAN CAUSE SLEEPINESS, FATIGUE, AND OTHER SYMPTOMS IN SECURITY GUARDS AND OTHER PERSONNEL WHO MUST STAND WATCH IN CLOSED ENVIRONMENTS (E.G., OFFICE BUILDINGS, DEPARTMENT STORES, WATCH TOWERS, SURVEILLANCE VANS). THE PROBLEM CAN BE HANDLED EASILY WITH NEGION GENERATORS. BUT CARE MUST BE TAKEN IN SELECTING AND INSTALLING GENERATORS. IT SHOULD BE DETERMINED THAT THE GENERATOR ACTUALLY EMITS NEGIONS AND DOES NOT EMIT OTHER, POTENTIALLY HAZARDOUS PRODUCTS. FACTORS TO CONSIDER IN INSTALLING A GENERATOR INCLUDE TEMPERATURE AND HUMIDITY RANGE, AIRFLOW PATHS, CLIMATE, LATITUDE, WINDOW LOCATION, CEILING HEIGHT, FURNISHINGS, AND ELECTRICAL MANCHINERY--ALL OF WHICH AFFECT ATMOSPHERIC IONS. SOURCES OF ADDITIONAL INFORMATION ON THE ION EFFECT ARE NOTED. (LKM)