What happens if you were to breathe poison ivy smoke, how long would the symptoms take to show. would it be hours?

Up to 48 hours: This is actually known to make people fairly sick, and if it happens, you'll know it.

Lung irritation: Burning poison ivy, poison oak, and poison sumac releases an oil, urushiol, when the leaf or other plant parts are bruised, damaged. It can be very dangerous because the allergens can be inhaled, causing lung irritation. It can cause adult respiratory distress syndrome that can result in death. There are special respirators for workers that may be exposed (e.g. Fire fighters).