Which of the following statements is/are TRUE in relation to the Maximum Mixing Depth (or Height) ‘$\mathrm{D}_{\max }$’ in the atmosphere?
- $\mathrm{D}_{\max }$ is always equal to the height of the layer of unstable air
- Ventilation coefficient depends on $\mathrm{D}_{\max }$
- A smaller $\mathrm{D}_{\max }$ will have a smaller air pollution potential if other meteorological conditions remain same
- Vertical dispersion of pollutants occurs up to $\mathrm{D}_{\max }$