Is second hand smoke really all that dangerous and unhealthy?

YES!!!: Secondhand smoke causes about 3400 deaths from lung cancer & up to 69, 000 deaths from heart disease each year, causes ear & respiratory infections & asthma. It contains hundreds of chemicals that are toxic/carcinogenic. Even a brief exposure can trigger a heart attack. Of course the more one is exposed the greater the hazard. And with secondhand smoke so bad, think how incredibly toxic smoking is.