Aerosol chemical exposure

Inhalation and direct skin contact are the most common routes of chemical exposure. The greatest exposure risk in handling potent compounds in an analytical laboratory therefore occurs when handling solid materials due to the potential to generate and inhale airborne dust particles of the compound. Once the potent material has been placed into solution, the airborne exposure risk is reduced and solutions of potent compounds may be handled in a manner similar to other nonpotent pharmaceutical compounds, assuming good laboratory practices are followed. Caution should be taken not to aerosolize the solutions since this could create an inhalation hazard. In addition, any sample solution spills should be adequately cleaned to prevent powder deposits of the compound from forming, which could potentially become airborne after the liquid has dried. 

Outside of military conflicts, exposure to sulfur mustard has occurred or may occur in work environments associated with chemical weapon materiel (e.g. storage depots, demilitarization facilities, research laboratories), during emergency response operations or remediation and decontamination activities, or during treaty verification activities in support of the Chemical Weapons Convention. Chemical weapons such as the vesicants are stiU considered potential military threats and terrorist targets. The most likely route of exposure to sulfur mustard is via aerosol/vapor exposure of the skin, eyes, and respiratory tract. 

The most common contamination exposure is by the respiratory route. Most chemical and biological agents are dispersed by aerosol, and most explosion scenes are very dusty and may contain toxic airborne particles. Bombs can be used to aerosolize chemical and biological agents. Clandestine drug labs frequently have caustic or toxic fumes or vapors. 

Hazardous chemical exposures can occur from aerosols, gases, and skin contaminants. Exposures can occur on an acute basis or result from chronic long-term exposures. Some substances, commonly used in the healthcare setting, can cause asthma or trigger attacks. Studies indicate scientific evidence linking cleaners and disinfectants, sterilants, latex, pesticides, volatile organic compounds, and pharmaceuticals to asthma. Many medications and compounds used in personal care products have known toxic effects. Although many medications pose hazards to workers. 

For exposure of reasons of observable discrepancy of results of the analysis simulated experiment with application synthetic reference samples of aerosols [1]. The models have demonstrated absence of significant systematic errors in results XRF. While results AAA and FMA depend on sort of chemical combination of an elements, method of an ashing of a material and mass of silicic acid remaining after an ashing of samples. The investigations performed have shown that silicic acid adsorbs up to 40 % (rel.) ions of metals. The coefficient of a variation V, describing effect of the indicated factors on results of the analysis, varies %) for Mn and Fe from 5 up to 20, for Cu - from 10 up to 40, for Pb - from 10 up to 70, for Co the ambassador of a dry ashing of samples - exceeds 50. At definition Cr by a method AAA the value V reaches 70 %, if element presences an atmosphere in the form of Cr O. At photometric definition Cr (VI) the value V is equal 40%, when the element is present at aerosols in the form of chromates of heavy metals. 

Exposures to chemicals may involve solids, liquids, or airborne matter as mists, aerosols, dusts, fumes (i.e. pm-sized particulates), vapours or gases in any combination. Many situations, e.g. exposure to welding fumes or to combustion products from fossil fuels, include mixtures both of chemicals and of physical forms. Quantification of exposure is then difficult. 

The toxicity of a substance is its capacity to cause injury once inside the body. The main modes of entry into the body by chemicals in industry are inhalation, ingestion and absorption through the skin. Gases, vapours, mists, dusts, fumes and aerosols can be inhaled and they can also affect the skin, eyes and mucous membranes. Ingestion is rare although possible as a result of poor personal hygiene, subconscious hand-to-mouth contact, or accidents. The skin can be affected directly by contact with the chemicals, even when intact, but its permeability to certain substances also offers a route into the body. Chemicals accorded a skin notation in the list of Occupational Exposure Limits (see Table 5.12) are listed in Table 5.2. Exposure may also arise via skin lesions. 

Industrial environments expose individuals to a plethora of airborne chemical compounds in the form of vapors, aerosols, or biphasic mixtures of both. These atmospheric contaminants primarily interface with two body surfaces the respiratory tract and the skin. Between these two routes of systemic exposure to airborne chemicals (inhalation and transdermal absorption) the respiratory tract has the larger surface area and a much greater percentage of this surface exposed to the ambient environment. Or dinary work clothing generally restricts skin exposures to the arms, neck, and head, and special protective clothing ensembles further limit or totally eliminate skin exposures, but breathing exposes much of the airway to contaminants. 

As stated earlier, inhalation is the main route of absorption for occupational exposure to chemicals. Absorption of gaseous substances depends on solubility ifi blood and tissues (as presented in Sections 2.3.3-2.3.5), blood flow, and pulmonary ventilation. Particle size has an important influence on the absorption of aerosols (see Sections 2.3.7 and 3.1.1). 

Oil accumulation in the lungs after long-term or high-level exposure to aerosols of polyalphaolefin may be a concern, based on observations of lipoid pneumonia in humans after prolonged intranasal application of mineral oil mists (Lushbaugh 1950) and the physical and chemical similarities between mineral oil and polyalphaolefins (i.e., both are composed predominately of aliphatic hydrocarbons). 

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