This question is for those that have quit smoking.
1) When you quit smoking did you cough up brown or black stuff up?
If yes, please answer the next question, if not, skip to question 3
2) If you did, how long did you cough it up for?
3) How long did you smoke?
4) How much did you smoke? Example, per day.
1) When you quit smoking did you cough up brown or black stuff up?
If yes, please answer the next question, if not, skip to question 3
2) If you did, how long did you cough it up for?
3) How long did you smoke?
4) How much did you smoke? Example, per day.