What are the causes of tuberculosis? How contagious is TB and can breathing clean air help?

Complicated question. Tb is mycobacterium tuberculosis. There are more than sever related mycobacterium species though. It is contagious..Very in fact if you have active pulmonary disease. Other forms are less infective or pose no threat transmit at all like bone infection (pott's puffy tumor). Can breathing clean air help..Well..It won't hurt. Thats what the TB sanitariums of the 16-20th centuries were doing.