part per million by volume
Concentrationexact by definition
A part per million by volume is 10⁻⁴ percent as a ratio, and it is the standard unit of gas-phase concentration: atmospheric CO₂ is 425 ppmv, and workplace exposure limits for solvent vapours are set in ppmv.
Watch out: For gases, ppm by volume and ppm by mass are different numbers, and the ratio between them is the ratio of molar masses. 1 ppmv of carbon monoxide in air is 0.97 ppm by mass; 1 ppmv of a heavy solvent vapour can be five or six times its ppm-by-mass value. Air-quality limits are almost always volumetric, and the mg/m³ equivalents printed beside them assume 25 °C and 101.325 kPa.
| 1 | 0.0001 |
One part per million by volume in every concentration unit
| 1,000,000 | part per trillion (ppt) | |
| 1,000,000 | nanogram per liter (ng/L) | |
| 1,000 | parts per billion (ppb) | |
| 1,000 | microgram per liter (μg/L) | |
| 1 | parts per million (ppm) | |
| 1 | part per million by volume (ppmv)this unit | |
| 1 | milligram per kilogram (mg/kg) | |
| 1 | milligram per liter (mg/L) | |
| 0.058418 | grain per US gallon (as CaCO₃) (gpg) | |
| 0.001 | part per thousand (ppth) | |
| 0.001 | gram per liter (g/L) | |
| 0.0001 | percent (%) | |
| 0.0001 | percent by weight (% w/w) | |
| 0.0001 | percent by volume (% v/v) | |
| 0.0001 | percent weight per volume (% w/v) | |
| 0.000001 | fraction (0–1) (fraction) |
Solvers that use concentration