What should i do if i live with smokers and i have a 3 month old baby and i can't move anywhere else?

Ask nicely: Ther is substantial evidence that second hand smoke is injurious to infants. If those you live with will not smoke outside (ask nicely) then perhaps you can have a hepa filter or air purifier in the babies room and limit exposure as much as possible. Ideally you should find a way to move out. Easier said than done.....

Avoid : You should avoid the smokers with your infant as much as possible. Cigarette smoke contains dozens to hundreds of chemicals that babies noses and lungs do not like. It encourages allergies and infections with persistent exposure.

Ask for their help: Sometimes smokers will accept that babies don't need the extra lung & ear infections & will agree not to smoke around the baby. Beyond that, you may be out of luck. Most have burned off nerve endings in their noses & can't detect how bad their hair & clothing smells.Continue to look for alternative housing if you can, its the safest setup.