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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 ...
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.
Airflow, or air flow, is the movement of air. Air behaves in a fluid manner, meaning particles naturally flow from areas of higher pressure to those where the pressure is lower. Atmospheric air pressure is directly related to altitude , temperature , and composition.
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 ...
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.