Aerosols testing

A Guidance Document on Acute Inhalation Toxicity Testing is being developed and presently exists as a draft (OECD 2004b). The document recommends the Acute Toxic Class (ATC) Method with a group size of three animals per sex, if the objective of the test is solely related to hazard classification. Limits for particle-size distribution of aerosolized test substances are suggested. The preferred mode of exposure is the nose-only, head-only, or head/nose-only exposure technique, because this mode of exposure minimizes exposure or uptake by noninhalation routes. 

Aerosols. Test atmospheres containing aerosols may be conveniently generated by a number of techniques including ... 

Plate 6. The Aerosol Test Room per Plate 7. The measured drop equipment... 

There are other compounds in the literature which seem to have a potentially useful blend of bronchodilator and antiallergy action. Compound IX, having a cromolyn-type structure, is effective in the passive cutaneous anaphylaxis test in rats as well as in the histamine aerosol test in guinea pigs (22). It has less cardiovascular effects than theophylline but causes some CNS stimulation. Compound X is a recent compound which in animals appears to be more potent than theophylline in its bronchodilator/antiallergic actions and also appears to have greater broncho-selectivity (23, 24). 

The following sections detail existing in vitro/in vivo correlations for the major aerosol modalities and, where appropriate, comparisons are made with lung model predictions. Measures of particle diameter, particle size statistics, and aerosol test methods are also discussed. Aerosol test methodologies are included in the discussion because, as described above, sizing results are highly dependent upon the method and apparatus used. The correlations that have been developed and any predictions that can be made from them are therefore specific to the use of particular experimental methods, and it is important that the applicability of the different instruments/methods be understood. 

From the Marviken large-scale aerosol tests (see Section 7.3.2.2.) it was reported that the aerosols remaining after passage of the simulated primary system were retained to at least 99% in the water-filled scrubber located at the back end of the test facility at a submergence depth of about 1 meter (Rahn et al., 1988). 

Ligotke, M. W., Eschbach, E. J., Winegardner, W. K. Ice-condenser aerosol tests. Report NUREG/CR-5768 (1991)... 

M. W. Ligotke, E. J, Eschbach, W. K. Winegardner, Ice-Condenser Aerosol Tests , NUREG/CR-5768, PNL-7765, Pacific Northwest Laboratories, September 1991. 

John, W., and Wall, S. M., Aerosol Testing Techniques for Size-Selective Samplers, J. Aerosol ScL, 14, 713-727 (1983). 

Fit testing may be either qualitative or quantitative. Quahtative fit testing (QLFT) involves the introduction of a gas, vapor, or aerosol test agent into an area around the head of the respirator user. If that user can detect the presence of the test agent through subjective means, such as odor, taste, or irritation, the respirator fit is inadequate. 

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