The legality has absolutely zero impact on whether using the drug is abuse.
You shouldn't abuse any drug whatsoever, especially not when children are around. Using a drug to a point where it negatively effects the user or the people around him is abusing it.
If you are using a drug which significantly impairs your ability to make decision or, even worse, is spreading through the air, using it near children is abusing that drug.
The legality has absolutely zero impact on whether using the drug is abuse.
You shouldn't abuse any drug whatsoever, especially not when children are around. Using a drug to a point where it negatively effects the user or the people around him is abusing it.
If you are using a drug which significantly impairs your ability to make decision or, even worse, is spreading through the air, using it near children is abusing that drug.