Respirable aerosols

Before discussing the three categories of delivery device, the nature of the emitted aerosol will be considered. Droplet formation may be characterized in terms of the nature of the propulsive force and the liquid being dispersed, and this topic is dealt with for specific situations in the following sections. However, dry particles, which are delivered from suspension in pMDIs or from DPIs alone or from a blend, must be prepared in respirable sizes. The production of respirable aerosol particles has traditionally been achieved by micronization of the drug [25]. This... 

Examples of such procedures are making dilutions (not all components of the mixture may be equally soluble or miscible with the vehicle) and generating either vapors or respirable aerosols (not all the components may have equivalent volatility or surface tension, leading to a test atmosphere that contains only a portion of the components of the mixture). 

Xnormal normal or total respirable aerosol dust concentration,... 

It has recently been noted that if copper-induced MEE does occur, it is a very rare event. Despite extensive use of copper in many industries, only a handful of MEE cases are reported in the literature. Further limitations of these reports include possible contamination of the fume by other substances more likely to have caused MFF, atypical symptoms and complaints, and lack of consistency among types of work associated with symptoms. One reason that MFF may have rarely been described after copper exposure is that aerosolized copper particulates formed during welding, thermal cutting, and other hot work are mostly greater than respirable or submicron size. Studies of air in a brass foundry found that only 5% of the total copper exposure was respirable (aerosol less than or equal to 1 )im), whereas 40% of the zinc oxide exposures were to an aerosolized particulate of respirable size. ... 

Weissman SH, Carpenter RL, Newton GJ. 1983. Respirable aerosols from fluidized bed coal combustion Element composition of fly ash. Env Sci Tech 17 65-71. 

The sampling sites were chosen in order to investigate the spatial distribution of particulate pollutants in the valley. As an additional consideration, sites were selected to coincide with the major population centers in the valley in order to determine the concentration of respirable aerosols to which valley residents are exposed on a dally basis. Seven of the sampling sites were in the Owens Valley itself, and one site was in the Mono Lake area. Site 1 was located near the Bishop Airport at the National Weather Service Meteorological station. This site is about five miles east of downtown Bishop in the center of the... 

Last, J. A., and D. L. Warren, Synergistic Interaction between Nitrogen Dioxide and Respirable Aerosols of Sulfuric Acid or Sodium Chloride on Rat Lungs, Toxicol. Appt. Pharmacol., 90, 34-42 (1987). 

The active inhaler made by Nektar Therapeutics (formerly Inhale Therapeutic Systems, United States), called Pulmonary Delivery System (PDS), mechanically compresses a fixed volume of air required for delivery and dispersion of a premetered dry-powder unit dose by a spring-loaded pump (Fig. 8.10). Generation of the respirable aerosol cloud thus is independent of the inspiration effort exerted by the patient. The aerosol is generated in a transparent holding chamber that acts as a spacer from which the patient inhales the standing cloud of particles (Patton 1997). The PDS device is actually close to market for inhaled delivery of insulin under the trade name Exubera. 

Although these reactions result in an increased respirable aerosol mass, little is known about human health effects associated with these particular condensed reaction products. Tamas et al. (2006) observed a correlation between the number concentration of SOAs, from the limonene-ozone reaction in an office, and sensory load reported by 20 human subjects. Additionally, a screening study indicates that perfume wearers will be subjected to a personal reactive cloud of reaction products, such as fine aerosols (Corsi et al., 2007). 

Important factors in determining the impact of sources in the residence on exposures are the nature of the source (e.g. consumer product or professional application), how it is released (fine respirable aerosols, non-respirable coarse... 

Liquid (sulfuric acid and cutting fluids) and solid (silica dusts, asbestos fibers, and microorganisms) particles may become airborne and form respirable aerosols. According to their size and diameter, inhaled particles may be deposited in different anatomical regions of the respiratory system. Once deposited, particles may dissolve locally or may undergo removal to other regions of the respiratory tree. 

The uses and relatively low vapor pressures of di- (0.00473 Torr, 0.63 Pa) and tri- (0.00018 Torr, 0.0239 Pa) ethanolamines result in primarily dermal exposure of humans. However, the somewhat higher vapor pressure of monoethanolamine (0.75 Torr, 100 Pa) indicates the potential added exposure for this ethanolamine via inhalation. The inhalation of any of the ethanolamines may also occur when respirable aerosols are generated during the use of consumer products or in occupational settings. 

Snyder, C.A. Wood, R.W. Graefe, J.F. Bowers, A. and Magar, K. "Crack smoke" is a respirable aerosol of cocaine base. Pharmacol Biochem Behav 29-.93-95, 1988. 

Vemez (Switzerland) 2006 Application of waterproofing sprays Respirable aerosol particles containing solvent Exposure estimate range (mg/m )... 

Eye, aerosol TC50 = 0.3 mg m-3 Respiration, aerosol TC50 = 0.4 mg m-3 IC50 aerosol = 20-25 mg m-3 ICfso (aerosol in acetone) = 40 mg min m-3 ICfso (grenade smoke) = 20 mg min m-3 (data after Ballantyne, 1977a McNamara et al., 1969)... 

The Subcommittee on Permissible Exposure Levels for Military Fuels judged that, on the basis of available data, DOD s PEL of 350 mg/m3 for the fuel vapors is adequate to protect the health of naval personnel exposed to them occupationally (NRC 1996). However, because of uncertainties in the database, the PEL should still be considered interim until further research has been completed. The subcommittee recommended that data be obtained on exposures during operational procedures, including exposure to respirable aerosols of unburned fuels that studies be conducted on the possible effects of high-level acute and low-level chronic exposure to fuel vapors on the central nervous system and that research be conducted on the effect of fuel vapors on hepatotoxicity in experimental animals to help to identify a no-observed-adverse-effect level for JP-8 with greater confidence. 

The subcommittee did not address the potential toxicity resulting from exposure to respirable aerosols of the total fuels. If the Navy finds evidence of potential for exposures to respirable aerosols, which are much more toxic, new recommendations for limiting such exposures will need to be developed. It is understood that the board intends to use the exposure levels for the three fuels to help determine ventilation requirements in the cargo holds of the new strategic sealift ships and to prevent toxic exposures of service personnel to these fuels. 

Because respirable aerosols of military fuels are much more toxic than vapors, naval personnel should avoid exposure to aerosolized fuel. If a potential for exposure to aerosolized fuel exists, protective clothing and respiratory equipment should be worn. 

Obtain information on exposures occurring during operational procedures, including exposures to respirable aerosols of unburned fuels. Samples should be talon in the breathing zone of the service personnel. Breath analysis of exposed personnel is recommended to determine the extent of individual exposures to fuel vapors. 

Because toxins are not volatile, as are chemical agents, and with rare exceptions, do not directly affect the skin, an aggressor would have to present toxins to target populations in the form of respirable aerosols, which allow contact with the more vulnerable inner surfaces of the lung. This, fortunately, complicates an aggressor s task by limiting the number of toxins available for an arsenal. Aerosol particles between 0.5 and 5 pm in diameter are typically retained within the lung. Smaller particles... 

Staphylococcal enterotoxins, when inhaled, cause fever, headache, diarrhea, nausea, vomiting, muscle aches, shortness of breath, and a nonproductive cough within 2 to 12 hours after exposure. They can also kill, but only at much higher doses. Staphylococcal enterotoxin B (SEB) can incapacitate at levels at least 100-fold lower than the lethal level. These toxins, too, would probably be delivered as respirable aerosols. 

The aerosol toxicity of even the most toxic trichothecene is low enough that the large-quantity production required (approximately 80 tonnes to expose a 10-km2 area with respirable aerosol) makes an inhalational threat unlikely on the battlefield. These toxins, therefore, might be dispersed as larger particles, probably visible in the air and on the ground and foliage. 

Recall that a true respirable aerosol will leave less residue on clothing and environmental objects than... 

Finally, for at least 12 to 24 hours after the exposure, toxins should be identifiable in nasal swabs from individuals exposed to a respirable aerosol. This may be the best approach to early diagnosis on the battlefield. 

The staphylococcal enterotoxins are a family of superantigen protein toxins produced by strains of Staphylococcus aureus. Staphylococcal enterotoxin B (SEB), a toxin often associated with food poisoning, was weaponized as an incapacitating agent by the United States during in the 1960s. When inhaled as a respirable aerosol, SEB causes fever, severe respiratory distress, headache, and sometimes nausea and vomiting. The mechanism of intoxication is... 

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