You are right, it's not consent. However staying somewhere when you were free to move away suggests there may of been some kind of acceptance. Of course if the pollution was undetectable at the time, then no.
I think I answered this, lighting a fire is not an act of agression, people do it to get warm, dispose of waste and such. So long as no one else is harmed then there's no reason to stop them assuming it's all done on their property. If someone is harmed then they should have a legal remedy, unless perhaps they were warned of the risk and stayed anyway. Theft and vandalism are acts of agression, there is no similarity, when these actions are carried out someone will definately be harmed.
You don't consent to breath in atmosphere that I have breathed either. We both have an equal claim to use atmosphere in a way we choose so long as we cause no harm. If you want to claim that someone is harming you then the onus is on you do demonstrate this.