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One part per billion (ppb) denotes one part per 1,000,000,000 (10 9) parts, and a value of 10 −9. This is equivalent to about three seconds out of a century . One part per trillion ( ppt ) denotes one part per 1,000,000,000,000 (10 12 ) parts, and a value of 10 −12 .
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).
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.
The concentration of a greenhouse gas is typically measured in parts per million (ppm) or parts per billion (ppb) by volume. A CO 2 concentration of 420 ppm means that 420 out of every million air molecules is a CO 2 molecule.
Globally averaged atmospheric concentration and its annual growth rate. [17] In April 2022, NOAA reported an annual increase in global atmospheric methane of 17 parts per billion (ppb) in 2021—averaging 1,895.7 ppb in that year—the largest annual increase recorded since systematic measurements began in 1983; the increase during 2020 was 15.3 ppb, itself a record increase.
Regardless of where it was emitted from, emissions are roughly spread across the world and become mixed into a heterogeneous mixture. They are calculated in parts per million (ppm), parts per billion (ppb), and parts per trillion (ppt). In 2019, data states that there was 409.8 parts per million of carbon dioxide in the atmosphere. [19]
Values are given as pollution free monthly mean mole fractions in parts-per-billion. [1] Atmospheric methane is the methane present in Earth's atmosphere. [2] The concentration of atmospheric methane is increasing due to methane emissions, and is causing climate change. [3] [4] Methane is one of the most potent greenhouse gases.
Ozone used in industry is measured in μmol/mol (ppm, parts per million), nmol/mol (ppb, parts per billion), μg/m 3, mg/h (milligrams per hour) or weight percent. The regime of applied concentrations ranges from 1% to 5% (in air) and from 6% to 14% (in oxygen) for older generation methods.