Dissolved oxygen (DO) concentration is typically measured in milligrams of dissolved oxygen per liter of water (mg/L).
Units of Measurement for Dissolved Oxygen
Based on measurement results, the concentration of oxygen dissolved in water is commonly expressed using specific units. The reference indicates that the results of dissolved oxygen measurement are usually expressed in the following ways:
- Milligrams per Liter (mg/L): This is a standard unit representing the mass of dissolved oxygen found in a given volume of water.
- Parts Per Million (ppm): This unit is equivalent to mg/L for dilute solutions like water and is also frequently used to express concentration. Thus, mg/L and ppm essentially represent the same concentration level.
Additionally, DO results are sometimes reported as the percent saturation. This value indicates how much dissolved oxygen is present compared to the maximum amount of oxygen that water can hold at a specific temperature and pressure.
Summary of Units
| Unit | Description | Notes |
|---|---|---|
| mg/L | Milligrams of oxygen per liter of water | Common standard unit |
| ppm | Parts per million | Equivalent to mg/L in water |
| Percent Saturation | Percentage of maximum possible dissolved oxygen | Relative measure, depends on temp/pressure |
Measuring dissolved oxygen is crucial for assessing water quality and supporting aquatic life, as insufficient DO levels can be detrimental to fish and other organisms. Higher mg/L or ppm values generally indicate healthier water conditions, provided they are within an appropriate range.
