pCO2

[citation needed] This is the highest atmospheric concentration to have existed on Earth for at least the last 800,000 years.

in the systemic circulation indicates the effectiveness of ventilation at the lungs' alveoli, given the diffusing capacity of the gas.

Values less than this may indicate hyperventilation and (if blood pH is greater than 7.45) respiratory alkalosis.

Values greater than 45 mmHg may indicate hypoventilation, and (if blood pH is less than 7.35) respiratory acidosis.

[2][3] Oceanographers and limnologists use pCO2 to measure the amount of carbon dioxide dissolved in water, as well as to parameterize its flux into (influx) and out of (efflux) the atmosphere.

Together, these parameters describe the concentration and speciation of inorganic carbon species (CO2 (aq), HCO3−, CO32-) in water.

This article incorporates text by Glynda Rees Doyle and Jodie Anita McCutcheon available under the CC BY 4.0 license.