The discussion of pH on this page concludes with the statement:

"Incidentally, the "p" prefix is also used with other types of chemical measurements where a logarithmic scale is desired, pCO2 (Carbon Dioxide) and pO2 (Oxygen) being two such examples."

\(P_{O_{2}}\) and \(P_{CO_{2}}\) refer to partial pressure of oxygen and carbon dioxide, respectively, and are not logarithmic.

 

So how would you correct it?

I generally show a before and after statement.

 

I would delete that sentence. It doesn't really add anything, and the only other example of that notation that I can think of right now is the dissociation constant of a weak acid (\(pK_a\)), which also wouldn't add to the reader's understanding of the concept of pH.