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= air pollutant concentration, in parts per million by volume mg/m 3 = milligrams of pollutant per cubic meter of air = atmospheric temperature in kelvins = 273.15 + °C 0.08205 = Universal Gas Law constant in atm·l/(mol·K) = molecular weight of the air pollutant (dimensionless)
The difference is quite significant when dealing with gases, and it is very important to specify which quantity is being used. For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74 ...
1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6. Care must be taken with the concentrations expressed as ppbv to differentiate between the British billion which is 10 12 and the USA billion which is 10 9 (also referred to as the long scale and short scale billion, respectively).
The concentrations of carbon dioxide in the atmosphere are expressed as parts per million by volume (abbreviated as ppmv, or ppm(v), or just ppm). To convert from the usual ppmv units to ppm mass (abbreviated as ppmm, or ppm(m)), multiply by the ratio of the molar mass of CO 2 to that of air, i.e. times 1.52 (44.01 divided by 28.96).
It is one way of expressing the composition of a mixture in a dimensionless size; mole fraction (percentage by moles, mol%) and volume fraction (percentage by volume, vol%) are others. When the prevalences of interest are those of individual chemical elements , rather than of compounds or other substances, the term mass fraction can also refer ...
When expressed in percent, it is known as the mole percent or molar percentage (unit symbol %, sometimes "mol%", equivalent to cmol/mol for 10 −2). The mole fraction is called amount fraction by the International Union of Pure and Applied Chemistry (IUPAC) [ 1 ] and amount-of-substance fraction by the U.S. National Institute of Standards and ...
Conversion to mass flowrate and molar flowrate [ edit ] For conversion purposes, it is useful to think of one SCCM as the mass flow rate of one cubic centimeter per minute of a fluid, typically a gas, at a density defined at some standard temperature, T n {\displaystyle T_{n}} , and pressure, p n {\displaystyle p_{n}} .
inhaled carbon monoxide induces unconsciousness in 2–3 breaths and death in < 3 min (12 800 ppm) [15] 10 −3: mM 0.32–32 mM: normal range of hydronium ions in stomach acid (pH 1.5–3.5) [16] 5.5 mM: upper bound for healthy blood glucose when fasting [17] 7.8 mM: upper bound for healthy blood glucose 2 hours after eating [17] 10 −2: cM 20 mM