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If a gaseous emission sample is analyzed and found to contain water vapor and a pollutant concentration of say 40 ppmv, then 40 ppmv should be designated as the "wet basis" pollutant concentration. The following equation can be used to correct the measured "wet basis" concentration to a " dry basis " concentration: [ 3 ]
Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water.The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution.
PM is most usually (but not always) expressed as mg/m 3 of air or other gas at a specified temperature and pressure. For gases, volume percent = mole percent; 1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6.
14] Water can be classified by the level of total dissolved solids (TDS) in the water: Fresh water: TDS is less than 1,000 ppm. Brackish water: TDS = 1,000 to 10,000 ppm. Saline water: TDS = 10,000 to 35,000 ppm. Hypersaline: TDS greater than 35,000 ppm. Drinking water generally has a TDS below 500 ppm.
For a dilute solution, such as NaCl in water, concentration is often expressed as weight of solute divided by mass of solution (typically assuming 1 g/mL for dilute water-based solutions) -- i.e., ppm by weight. Mass/volume notation such as micrograms/mL is also used for liquid solutions. Low concentrations of pollutant gases in air are often ...
Since it is a gas under most ambient conditions, primary exposure is via inhalation, as opposed to the consumption of contaminated food or water, with occupational hazards being highest. Prior to 1974, workers were commonly exposed to 1,000 ppm vinyl chloride, causing "vinyl chloride illness" such as acroosteolysis and Raynaud's Phenomenon.
Toxic: a chemical that has a median lethal concentration (LC 50) in air of more than 200 parts per million (ppm) but not more than 2,000 parts per million by volume of gas or vapor, or more than 2 milligrams per liter but not more than 20 milligrams per liter of mist, fume or dust, when administered by continuous inhalation for 1 hour (or less if death occurs within 1 hour) to albino rats ...
Refrigerant concentration limit / immediately dangerous to life or health in parts per million (volume per volume) and grams per cubic meter Molecular mass in atomic mass units Normal boiling points for pure substances, bubble and dew points for zeotropic blends, or normal boiling point and azeotropic temperature for the azeotropic blends, at ...