Your questions doesn't make sense.
pH is a concept related to the water solution, there is no such thing as pH of a gas. Air can't be alkalic nor acidic. Humidity can't be alkalic nor acidic, as humidity means gaseous water. Gaseous, not liquid, so no pH.
Could be you are asking about aerosol, that's the only way your questions may make sense, but I am not going to venture a guess.
Please elaborate on what you mean. As of now your question can't be understood nor answered.