From The BBC: 

Too much bacon ‘bad for lungs’

Eating large quantities of cured meats like bacon could damage lung function and increase the risk of lung disease.

A Columbia University team found people who ate cured meats at least 14 times a month were more likely to have COPD - chronic obstructive pulmonary disease.

COPD, which includes chronic bronchitis and emphysema, kills around 30,000 people in the UK each year.

The report, in the American Journal of Respiratory and Critical Care Medicine, said nitrites in meat may be to blame.

(more here)