It's not okay to be overly paranoid about things.
Henry is surfing the Internet when he sees a website about planes spraying chemicals in the air to shorten people's lifespans.
Henry wants to protect himself.
Henry stays inside a bit more and does more research to figure out what the chemicals are and how to avoid them.
Henry wears a chemical warfare mask whenever he goes outside to prevent inhaling the chemicals.
Henry's friends hardly notice anything strange about him and treat Henry normally.
Henry's neighbors and friends are weirded out by Henry's strange behavior and beliefs.