Want smoking roommate to pay for an air purifier

My roommate has started smoking in the house. The moment I leave for work, I know he is lighting one up. The whole house reeks of cigarettes. I am worried about the walls discoloring, the curtains getting stained and second hand smoke. I don’t smoke, so I don’t want to get lung cancer from second hand fumes. I have tried to get my roommate to smoke outside, he swears he is. Rather than getting in a knock out drag out over a cigarette, I think I am going to get an air purifier. An air purification system removes contaminants from the home indoor air quality. The air purification system is best for allergy sufferers and for people who are health conscious like myself. I found that the air purifier that I want can fit right into our current HVAC unit. As the heater or AC plan turns on, the air purifier will work in tandem. So even if the cigarette fumes get sucked up in the HVAC, the air cleaner will remove the smell before I get home from work. This will stop the smells and the potential health risks for me. I have found air purifiers online as cheap as 50 bucks and as expensive as 300 dollars. The one I want will cost around 150 dollars. I want my roommate to split this expense with me. He is the reason I have to buy this air quality device. He should at least have to give me a few bucks towards it. I am not thinking this is going to go over well though.

air cleaner