# Saturation dissolved oxygen level at pressure

The saturation level of dissolved oxygen in contact with a moist atmosphere is

$$c = 0.21(p_\mathrm{atm} - p_\mathrm{vap}) K_\mathrm{H} M$$

where the $$p_\mathrm{atm}$$ and $$p_\mathrm{vap}$$ are the atmospheric and vapour pressures, respectively; $$K_\mathrm{H}$$ is the Henry's law constant, and $$M$$ is the molar mass.

If I take this volume of water away from the atmospheric interface, and reduce the pressure, does the saturation level equation stay the same as above, except swapping out $$p_\mathrm{atm}$$ for $$p_\mathrm{local}$$?

• Yes, if p-local is made up of air and water vapor and the water vapor partial pressure at local is included. But this will be when the system re-equilibrates. – Chet Miller May 3 at 13:38