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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).
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).
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. 1 percent by volume = 10,000 ppmv (i.e., parts per million by volume).
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.
Agents on patrol discovered two backpacks stuffed with more than $1.1 million worth of cocaine in Washington state near the border with Canada, U.S. Customs and Border Protection said Monday. The ...
After 2014, the increase accelerated and by 2017, it reached 1,850 (parts per billion) ppb. [52] The annual average for methane (CH 4) was 1866 ppb in 2019 and scientists reported with "very high confidence" that concentrations of CH 4 were higher than at any time in at least 800,000 years. [14]
The Federal Aviation Administration issued temporary flight restrictions prohibiting drone flights over parts of New Jersey following an influx of sightings in recent weeks.. The notice, which ...