GOOGLE TO THE RESCUE!!! Solvent abuse: Solvent abuse is the use of various inhalants for the purpose of achieving a "high". They are often used as a cheap, readily available alternative to street drugs but they can cause serious damage to the body. Solvents include nail polish removers, paint thinners, gasoline, typing correction fluid and toxic markers. These solvents can be abused by sniffing them, spraying directly into the mouth, heating them and then inhaling them or injecting them directly into the body.
It's like most things. It can only be dangerous if you inhale too much. So if you use air freshener then the diffusion of the gas will mean that you won't have any problems.
@arlo(View Post) You know how people sniff glue? That is illegal, and is sniffing a solvent. Solvents can be classed as a drug, so some shops do not sell glue unless the customer produces some ID to prove he or she is old enough to buy that glue. Air fresheners, I would guess, are some type of mild solvent. Sniffing them wouldn't kill you, but probably digestion of the substance inside the air frensher cage would harm or kill you.