Inhalants definition

Within 30 seconds ofthe initial inhalation, definite changes in the smoker s perception should be apparent. As the salvinorin A enters the bloodstream, the smoker will feel a humming and tingling which ripples in waves all over the body. The "peak" of the experience will occur within a minute, and typically continue for as long as two to three minutes. The sensation abruptly tapers off after this point, leaving one quite near baseline within seven... 

Toxicology. The acute oral and dermal toxicity of naphthalene is low with LD q values for rats from 1780—2500 mg/kg orally (41) and greater than 2000 mg/kg dermally. The inhalation of naphthalene vapors may cause headache, nausea, confusion, and profuse perspiration, and if exposure is severe, vomiting, optic neuritis, and hematuria may occur (28). Chronic exposure studies conducted by the NTP ia mice for two years showed that naphthalene caused irritation to the nasal passages, but no other overt toxicity was noted. Rabbits that received 1—2 g/d of naphthalene either orally or hypodermically developed changes ia the lens of the eye after a few days, foUowed by definite opacity of the lens after several days (41). Rare cases of such corneal epithelium damage ia humans have been reported (28). Naphthalene can be irritating to the skin, and hypersensitivity does occur. 

Asbestos and other fibers in a wide variety of bundle sizes or even individual fibrils are in commercial usage. The handling of asbestos and other fibers causes degradation of the larger fiber bundles to fibers having diameters less than two micrometers that remain airborne for extended periods of time. These airborne fibers are prone to inhalation and lung entrapment. The exact definition of harmfiil fibers and the mechanism by which they affect the body is not accurately known. 

Some authorities question whether dmnkeimess can result from the inhalation of ethyl alcohol vapors. Experience has demonstrated that in any event such intoxication is indeed rare (281). There is no concrete evidence that the inhalation of ethyl alcohol vapor will cause cirrhosis. Liver function is definitely impaired during alcohol intoxication (282), making the subject more susceptible to the toxic effects of chlorinated hydrocarbons. 

Refer to the handbook s Glossary. The definitions provided are universally recognized. Many of these terms are not just pertinent to inhalation hazards. It would be remiss not to mention other risks beyond inhalation from chemical exposure in a work environment and to the general public. 

Threshold lamit Value - The term refers to toxicity by inhalation. The abbreviation used is TLV. The TLV is usually expressed in units of parts per million (ppm) - i.e., the parts of vapor (gas) per million parts of contaminated air by volume at 25 °C (77°F) and atmospheric pressure. For chemicals that form a fine mist or dust, the concentration is given in milligrams per cubic meter (mg/m ). The TLV is defined as the concentration of the chemical in air that can be breathed for five consecutive eight-hour workdays (i.e., 40 hours per week) by most people without suffering adverse health effiects. This is the definition given by the American Conference of Governmental Industrial Hygienists. 

Test Species/Strain/Sex/Number Squirrel monkeys, 2-4 males/group Exposure Route/Concentrations/Durations Inhalation exposure at 300,340, or 376 ppm for 15 min 130, 150, or 170 ppm for 30 min 75, 85, or 90 ppm for 60 min Effects Data specifically identifying serious, irreversible effects consistent with the AEGL-2 definition were not available. The lethality data are shown in the summary table for AEGL-3. 

Data on acute exposures of humans to both isomers of dimethylhydrazine are limited to case reports of accidental exposures. Signs and symptoms of exposure include respiratory irritation, pulmonary edema, nausea, vomiting, and neurologic effects. However, definitive exposure data (concentration and duration) were unavailable for these accidents. The limited data in humans suggest that the nonlethal toxic response to acute inhalation of dimethylhydrazine is qualitatively similar to that observed in animals. No information was available regarding lethal responses in humans. In the absence of quantitative data in humans, the use of animal data is considered a credible approach for developing AEGL values. 

Few data were available that met the definitions of AEGL end points. One inhalation study with 20 human subjects described headaches and slight loss of balance at exposure concentrations of 0.1 to 1.5 ppm for exposure durations of up to 8 h (Stewart et al. 1974). Acute exposure of monkeys for 6 h at concentrations ranging between 70 and 100 ppm resulted in severe signs of toxicity including convulsions but no deaths (Jones et al. 1972). In the same study, exposure of rats at a higher concentration, 189 ppm for 4 h, resulted in no toxic signs. Examination of the relationship between exposure duration and concentration for both mild and severe headaches in humans over periods of 1 to 8 h determined that the relationship is C xt=k. 

The inhalation exposure CNT toxicology study by Li et al. (2007a, b) was significant because dispersion of CNTs in air for inhalation studies is troublesome and CNTs have a tendency to aggregate together. Thus, before this work it was difficult to perform definitive inhalation studies. 

According to an estimate in early 2000s, 12% of the pharmaceutical market comprises DDSs. This share will definitely increase in the future as it is evident from some of the considerations made above. Among the market share of various DDSs, oral dosage forms account for approximately 60%, inhalation products for 20%, transdermal about 10%, and injectables around 9%.119... 

Reproductive Effects. It has not been definitively determined whether chloroform exposure induces reproductive effects in humans. No studies were located regarding reproductive effects in humans after inhalation or dermal exposure to chloroform. Only one study was located regarding reproductive effects in humans after oral exposure to chloroform. Bove et al. (1995) studied the effects of drinking-water consumption on birth outcomes and found that exposure to TTHM at levels >0.1 ppm resulted in reduced birth weight and size as well as an increased risk of oral cleft, central nervous system, and neural tube defects. These results should be viewed with caution since the authors did not specifically monitor chloroform levels. The effects seen may be due to exposure to other THMs or non-THM contaminants in the drinking water. 

The inhaled air volume (V in L) depends on the extent of chest enlargement. During normal breathing, the inhaled and exhaled volumes (tidal volume) are only part of the total lung volume [8,21]. The different parameters that describe pulmonary ventilation are shown in Figure 3.2. Table 3.1 presents a definition of the different parameters. Normal adults have a tidal... 

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