Can you break a lease due to health problems cause by the house?

I believe you can break the lease. It is easy to find a sympathetic doctor and even easier to find a sympathetic judge. In this case you will have to take your landlord to court and sue him to break the lease. This is a quality of life issue. Your landlord can argue that he/she cannot do anything about the smoking. You argue that the smoking is affecting the quality of your life and health and have a written medical opinion to that effect. The judge will likely rule that yes, the landlord cannot control the habits of his/her tenants; and yes, if your health and/or quality of life is in question then the landlord can find another tenant. Lease terminated. People often make the assertion that breaking a lease is the hardest thing in the world. It isn't. And yes, it is a contract between you and your landlord and you should try to work out a reasonable alternative with your landlord before going to court. But remember that a contract is not a one way street. You have obligations to your landlord and your landlord, by contract of the lease, has obligations to you. Court should be the course of last resort. When breaking a lease, it is often necessary to nullify it legally, for the sake of your peace of mind and monetary liability.