No, it doesn't have to be dry. You are not at risk from touching or hand jobs (taken as your risk from another thread). Air WILL inactivate HIV and no one gets HIV in this manner.
Infected fluid can't infect outside of it's host, contact with the environment would cause it to become uninfectious.
Is there a risk that you are worried about? Asking random question with out discussing a situation mostly turns out to be an irrational fear, we have seen that a lot here on this forum.