Do you know why the gas pipe would smell bad when it rains?

It does NOT smell like rotten eggs. It smells like chemicals. It's in a closet with what I think is a gas vent pipe or something. It smells SO STRONG when it rains.

Any thoughts?


My brother looked at it, and he doesn't understand it. He's pretty smart, too.


Oh, yeah. Hurricane is supposed to hit tomorrow. So, the fumes will be STRONG. It is difficult to breathe normally when it rains that hard. The chemical smell is really strong. I don't understand why.