| Prefix |
Factor |
Fraction |
| centi |
10–2 |
1/100
(part per hundred) |
| milli |
10–3 |
1/1,000
(part per thousand) |
| micro |
10–6 |
1/1,000,000
(ppm, part per million) |
| nano |
10–9 |
1/1,000,000,000
(ppb, part per billion) |
| pico |
10–12 |
1/1,000,000,000,000
(ppt, part per trillion) |
| femto |
10–15 |
1/1,000,000,000,000,000
(ppq, part per quadrillion) |
| atto |
10–18 |
1/1,000,000,000,000,000,000
(part per quintillion) |
|
Globally Harmonized System of classification and labelling of chemicals (GHS)