491.5 mg/L = 491.5 ppm
| mg/L | ppm |
|---|---|
| 476.5 mg/L | 476.5 |
| 481.5 mg/L | 481.5 |
| 486.5 mg/L | 486.5 |
| 491.5 | 491.5 |
| 496.5 mg/L | 496.5 |
| 501.5 mg/L | 501.5 |
| 506.5 mg/L | 506.5 |
491.5 mg/L = 491.5 ppm
1 ppm = 1 mg/L (aqueous, density ≈ 1 kg/L) · 1 ppb = 0.001 mg/L · 1% = 10,000 ppm