Here are some solutions for cat owners who smoke:

Quit smoking or smoke on the balcony: If you keep a cat at home and the family members like to smoke, the best way is to quit smoking. If you really can't quit, smoke in a place where the cat can't reach it, otherwise secondhand smoke is very harmful to the cat.
Place the litter box on the balcony or near a window: If the litter box is in a high-traffic area such as the living room or bedroom, it can easily allow odors from the air to spread into the room. Placing the litter box on the balcony or near a window can reduce odors.