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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
The amount of pollutant present in air is usually expressed as a concentration, measured in either parts-per notation (usually parts per billion, ppb, or parts per million, ppm, also known as the volume mixing ratio), or micrograms per cubic meter (μg/m³).
Criteria can be set in different units (e.g. μg/m 3, parts per billion by volume (ppbv), parts per billion by mass (ppb (mass)), parts per million (ppm)) and it is possible to convert between all of these units if the molecular mass of the pollutant and the temperature are known. Different standard temperatures are used throughout the world ...
2 mg/kg 2 parts per million 2 ppm 2 × 10 −6: A mass fraction of... 2 μg/kg 2 parts per billion ! 2 ppb ! 2 × 10 −9: A mass fraction of... 2 ng/kg 2 parts per trillion ! 2 ppt ! 2 × 10 −12: A mass fraction of... 2 pg/kg 2 parts per quadrillion ! 2 ppq ! 2 × 10 −15: A volume fraction of... 5.2 μL/L 5.2 parts per million 5.2 ppm 5.2 ...
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 ...
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).
Atmospheric chemistry is a branch of atmospheric science that studies the chemistry of the Earth's atmosphere and that of other planets. This multidisciplinary approach of research draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and volcanology, climatology and other disciplines to understand both natural and human-induced changes in atmospheric ...