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0.1 × ( 12 ÷ 8 ) = 0.15 grain per dscf when corrected to a gas having a specified reference CO 2 content of 12 volume %. Notes: Although ppmv and grains per dscf have been used in the above examples, concentrations such as ppbv (i.e., parts per billion by volume), volume percent, grams per dscm and many others may also be used.
= milligrams of pollutant per cubic meter of air at sea level atmospheric pressure and T: ppmv = air pollutant concentration, in parts per million by volume T = ambient temperature in K = 273. + °C 0.082057338 = Universal gas constant in L atm mol −1 K −1: M = molecular mass (or molecular weight) of the air pollutant
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). For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv).
kilogram per cubic metre (SI unit) kg/m 3: ≡ kg/m 3 = 1 kg/m 3: kilogram per litre kg/L ≡ kg/L = 1000 kg/m 3: ounce (avoirdupois) per cubic foot oz/ft 3: ≡ oz/ft 3: ≈ 1.001 153 961 kg/m 3: ounce (avoirdupois) per cubic inch oz/in 3: ≡ oz/in 3: ≈ 1.729 994 044 × 10 3 kg/m 3: ounce (avoirdupois) per gallon (imperial) oz/gal ≡ oz ...
A 2002 study found that "Each 10 μg/m 3 elevation in fine particulate air pollution was associated with approximately a 4%, 6% and 8% increased risk of all-cause, cardiopulmonary, and lung cancer mortality, respectively."
The driving force shown here as ' ' is expressed in units of moles per unit of volume, but in some cases the driving force is represented by other measures of concentration with different units. For example, the driving force may be partial pressures when dealing with mass transfer in a gas phase and thus use units of pressure.
Average levels of PM 2.5 were measured using aqicn.org's World Air Quality Index data, and a formula developed by AirNow was used to convert the PM 2.5 figure into micrograms per cubic meter of air (μg ⁄ m 3) values. Among the 70 capital cities investigated, Baghdad, Iraq is the worst performing one, with PM 2.5 levels going up +31.6 μg/m 3.
O 3 and NO 2 are measured in parts per billion (ppb) while PM2.5 is measured in micrograms per cubic metre (μg/m 3). The AQHI is calculated on a community basis (each community may have one or more monitoring stations).