PURIFICATION SYSTEM

A purification system for purifying exhaust gas from an engine includes a separation part that separates oxygen and nitrogen contained in air, an ozone generation part that generates ozone from oxygen separated by the separation part, and a supply part that supplies ozone generated by the ozone generation part to an intake pipe and an exhaust pipe of the engine. The purification system includes a supply control device that adjusts an amount of ozone supplied to the intake pipe and an amount of ozone supplied to the exhaust pipe according to a purification rate of exhaust gas of the engine.