Yes, yes and yes...
First, its different for everyone, someone may be subjected to 20 years and never show any signs of second hand smoke, for others, they might not be SO lucky.
I can only say that everyone who smokes or is subjected to 2nd hand smoke will feel SOME effects, to one degree or another - buts it different for everyone. Some peoples 'constitution' and genetics allows them to get away with more than others.
In any case, sure, its not good for asthma - anyone with asthma or COPD of any kind, should NOT be subjected to smoke, pets, dust, mold, pollen, etc.
But I can tell you this with 100% certainty - that I see folks everyday who abused their bodies and paid the price.... heart attacks, respiratory distress or arrest, cancer, illnesses at 40-45 yrs old that should NOT be happening so soon, etc.
Yes, its REALLY that bad.... there is a quote thats says something like "There re over 400 or 4000 contaminants when you light up a smoke that you inhale." Its true.
Best of luck,
PS Anything that you put into your body that is foreign, be it smoke, Rx's, drugs, etc. is not supposed to be there -and everyhting has a action and reaction.....
Even DIR has chapters on fitness in diving, exercise, etc.