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Air Sanitizers

DIS/TSS-11 / Sep. 3, 1980
Air Sanitizers

These requirements apply to products with label claims for the treatment of air to reduce the numbers of airborne microorganisms.

  1. General.
  2. There is considerable evidence that glycol vapors produce significant decreases i/n numbers of viable airborne bacteria under relatively wide conditions of relative humidity and temperature when properly and continuously dispensed by a vaporizing device so as to maintain suitable concentrations in the air of enclosed spaces.

    With dispensers for the intermittent treatment of air, such as pressurized aerosols, several investigators have shown that glycols (triethylene, dipropylene, or propylene glycol) at concentrations of 5% or more in such formulations will temporarily reduce numbers of airborne bacteria when adequate amounts are dispensed under relatively ideal conditions.

    For other types of products intended for the treatment of air, claims for reducing numbers of airborne microorganisms will be considered, providing supporting experimental data are submitted to justify such claims.

  3. Test Standard
  4. No standard method for evaluating air sanitizers has been adopted. Refer to the attached references for information on testing products intended for sanitizing the air of enclosed spaces. Proposed testing protocols for studies of this kind may be submitted for review and evaluation by the Agency prior to initiation of the tests.

    1. Glycol Products.
    2. For products containing at least 5% glycols (triethylene, dipropylene, and/or propylene glycols), quantitative chemical determinations must be performed, using an air sampling device, to show the concentration of glycol vapor achieved with the product, used as directed, in an enclosed experimental room or chamber. (Note: Until the proposed Product Performance Guidelines are finalized, testing requirements are being deferred for products of this type. Currently, efficacy requirements are satisfied by the chemical formula statement showing appropriate glycol content.) DIS/TSS-11 3 Sept. 80

    3. Other Products.
    4. For products other than those specified in (b)(l), quantitative microbiological assays must be performed, using an air sampling device, to show the level of reduction of viable microorganisms achieved with the product, used as directed, in an enclosed experimental room or chamber. The primary test bacteria are Staphylococcusaureus ATCC 6538 and Klebsiellapneumoniae ATCC 4352. If the product is intended for use in hospital or medical environments, tests with Pseudomonasaeruginosa ATCC 15442 are also required.

    5. The methodology employed, such as spraying and sampling procedures, and the environmental conditions in the room or chamber, such as temperature, relative humidity, etc., must be reported. Raw data, as well as any statistical or graphical interpretation of the results, must be included in the reports.

  5. Performance Standard.
  6. For products containing at least 5% glycols, the results must show that adequate vapor concentrations (50% saturation or more) are achieved in the air of the test enclosure. [Note: See (b)(l) above for current policy in this regard.] For other products, the results must show a viable count reduction of at least 99.9% over the parallel untreated control, after correcting for settling rates, in the air of the test enclosure with each of the required test bacteria.

  7. Claims.
  8. Adequate experimental data is available to show that air sanitizers do not sterilize, disinfect, act as a germicide, or protect experimental animals from infections by airborne bacteria or viruses. Thus, claims of value in preventing or treating diseases, or providing any other health protection, whether expressed or implied, are not acceptable. Claims must clearly indicate the mitigating nature of the activity, such as "Temporarily reduces the number of airborne bacteria."

  9. Directions For Use.
  10. The label directions for use of air sanitizers must state:

    1. That application be made in closed spaces ("Close all doors and windows; close air vents or turn off air conditioners.");

    2. The duration and frequency of spraying;

    3. How the spraying should be conducted;

    4. The relative humidity necessary for maximum effectiveness.

    With glycols and glycol mixtures intended for use in continuous vaporizing devices, the vaporizers themselves do not require registration. However, since their use is an integral part of the directions for use of the pesticide product, the labeling used in connection with the sale of the vaporizer is collateral to the labeling of the pesticide and must be submitted as a part of the registration.


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Challinor, S.W. and J.P. Duguid. 1944. Propylene glycol as an air disinfectant. I. Edinburgh Med. J. 51:280-289.

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Puck, T.T., O.H. Robertson, and H.M. Lemon. 1943. The bactericidal action of propylene glycol vapor on microorganisms suspended in air. II. The influence of various factors on the activity of the vapor. J. Exper. Med. 78:387-406.

Puck, T.T. 1947. The mechanism of aerial disinfection by glycols and other chemical agents. II. An analysis of the factors governing the efficiency of chemical disinfection of the air. J. Exper. Med. 85:729-757.

Robertson, O.H., E. Bigg, B.F. Miller, Z. Baker, and T.T. Puck. 1941. Sterilization of air by certain glycols employed as aerosols and vapors. Trans. Assoc. Am. Physicians 56:353-358; Science 93: 213-14.

Robertson, O.H. 1943. Sterilization of air with glycol vapors. Harvey Lect. 38:227-254.

Robertson, O.H., B.F. Miller, and E. Bigg. 1943. Method of sterilizing air. U. S. Patent No. 2,333,124.

Rosebury, T. 1947. Experimental Airborne Infection. Williams and Wilkens, Baltimore.

Stuart, L.S. and J.L. Friedl. 1955. Testing aerosol products for germicidal and sanitizing activity. Proc. Chem. Specialties Manufact. Assoc., pp. 93-97.

Wolf, H.W., et al. 1959. Sampling microbiological aerosols. Public Health Service Publication No. 686, Washington.

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