Do you have a garage that is a separate building from your
home? This is the best arrangement. You can move all the
basement chemicals into this garage. Things that will freeze, such
as latex paint, you may as well discard. But if your garage is
attached, you have a problem. Never, never use your door
between the garage and house. Walk around the outside. Don't
allow this door to be used. Tack a sheet of plastic over it to slow
down the rate of fume entrance into the house. Your house acts
like a chimney for the garage. Your house is taller and warmer
than the garage so garage-air is pulled in and up as the warm air
in the house rises. See the drawing.
In medieval days, the barn for the animals was attached to the house. We think such an arrangement with its penetrating odors is unsavory. But what of the gasoline and motor fumes we are getting now due to parked vehicles? These are toxic besides! This is even more medieval.
If your garage is under your house, you cannot keep the
pollution from entering your home. In this case, leave the cars
and lawnmower outside. Remove cans of gasoline, solvents, etc.
Put up a separate shed for these items.