Air cleaners: a review.

Air cleaners are manufactured by many companies in the United States. Air cleaning devices vary widely in design, methods of operation, cost, and level of efficiency. No universally accepted performance standards are available to compare the capabilities of the available air cleaners. These units are classified as household appliances, not as medical devices. Clinical studies have failed to substantiate a significant impact of air cleaners on patients' symptoms. Air cleaners should be used when it is desirable to further reduce airborne contaminant concentrations that are not eliminated by other environmental control measures. Air cleaners should not be the primary means of improving indoor air quality.