Mists definition

Classically, aerosols are particles or droplets that range from about 0.15 to 5 p.m ia size and are suspended or dispersed ia a gaseous medium such as air. However, the term aerosol, as used ia this discussion, identifies a large number of products which are pressure-dispensed as a Hquid or semisohd stream, a mist, a fairly dry to wet spray, a powder, or even a foam. This definition of aerosol focuses on the container and the method of dispensiag, rather than on the form of the product. 

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. 

Methane, See also Liquefied natural gas Natural gas, 41, 47, 258, 291, 484 physical properties, 295 vapour pressure, 294 Micro-organisms, 1, 138 Mineral acids, 27, 28 Mineral oils, 15, 159, 166 Mists, See also Aerosols definition, 14 origin, 51... 

The concise scientific definition of an aerosol refers specifically to a colloidal state of material suspended in a gas. However, the term has acquired an additional meaning in common household usage. In the commercial packaging field, the term aerosol now is synonymous with pressurized products that are released in a dispersed form from a can or a bottle. The discharge ranges from coarse fogs and mists to finely divided liquid or powder dispersions. 

The many words employed to describe particulate systems attest to their ubiquity and to ilie impression they have made on humans from early times. Smoke, dust, haze, fume, mist, and soot are all terms in common use with somewhat different popular meanings. Thus dust usually refers to solid particles produced by disintegration processes, while smoke i nd fume particles are generally smaller and formed from the gas phase. Af/.vr.v are composed of liquid droplets. Soot usually refers to small carbon particles generated in fuel combu.stton but is now frequently used to describe very fine solid particles of silica and other inorganic oxides generated intentionally in industrial processes. In this text, however, we will rarely employ these special terms because of the difficulty of exact definition and the complexity of many real systems composed of mixtures of particles. Instead, we employ the generic term aeiosol to describe all such sy.siems of small particles suspended in air or another gas. 

The second edition consists of an introduction, four sections, and two appendices. (The appendices present examples and are not part of the consensus document.) Section 1 identifies the scope of the standard and section 2 lists definitions for particular terms. Thus, paraphrasing, adequate ventilation refers to a condition in which air contaminant concentrations are below levels that cause injury or illness, or, that the vapors of flammable liquids are well below the lower flammable limit. A toxic chemical has an oral LD50 for edbino rats greater than 50 mg/kg but not greater than 500 mg/kg, or a 24 hr. skin contact LD50 for albino rabbits more than 200 mg/kg but not more than 1000 mg/kg, or an inhalation LC50 for albino rats more than 200 ppm but not more than 2000 ppm of gas or vapor or more than 2 mg/f but not more than 20 mg/f of dust or mist, provided that such exposures are reasonably likely to be encountered by humans in their use of the chemical. 

In 1988, directive 80/1107/EEC was amended for the last time by EU directive 88/642/EEC [6-4]. It contained several additions concerning the procedure for exposure measurements and setting occupational limit values. The newly implemented annex Ila contained important and useful information on the updated definition of particulate matter (dust, fume, and mist) and on the exposure measurement strategy, with detailed descriptions of sampling conditions, especially for dusts. 

Fog Aerosols of liquid droplets. In some definitions, fog is characterized by a particular droplet size range, whereas in others, fog refers to mist having a high enough droplet concentration to obscure visibUity. 

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