Units
| Quantity | Unit | Symbol |
|---|---|---|
| Acidity/alkalinity | pH | pH |
| Area | hectare | ha |
| square kilometre | km2 | |
| Electrical conductivity | microsiemens per centimetre | µS/cm |
| Length | micrometre | µm |
| millimetre | mm | |
| centimetre | cm | |
| metre | m | |
| kilometre | km | |
| Mass | microgram | µg |
| kilogram | kg | |
| tonne | t | |
| megatonne | Mt | |
| gigatonne | Gt | |
| Power | megawatt | MW |
| kilowatt-hour | kWh | |
| gigawatt-hour | GWh | |
| Time | second | s |
| hour | hr | |
| day | d | |
| year | y | |
| Velocity and speed | kilometres per hour | km/hr |
| metres per second | m/s |
| Quantity | Unit | Symbol |
|---|---|---|
| Volume | cubic metre | m3 |
| Volume (fluids) | litre | L |
| kilolitre | kL | |
| megalitre | ML | |
| gigalitres | GL | |
| gigalitres per year | GL/y | |
| Work and energy | petajoule | PJ |
| Other abbreviations | carbon dioxide equivalent units | CO2-e |
| parts per million | ppm | |
| micrograms per cubic metre | µg/m3 |
Prefixes for SI units
| Fraction | Prefix | Symbol |
|---|---|---|
| 10–6 | micro | µ |
| 103 | kilo | k |
| 106 | mega | M |
| 109 | giga | G |
| 106 | peta | P |