Fumes are unhealthy
Volatile fumes from gasoline, glue, paint, etc.
.., are bad because they diffuse throughout the body after inhalation. The fumes one smells at a gas station are diluted by the air, so don't cause illness. If one purposely sniffs gasoline or glue, or accidentally gets too much fumes while painting inside a closet, he can get damage to the lungs, brain, etc..., especially with repeated exposures.