How do you protect your lungs if you CAN'T avoid secondhand smoke?!

In general it is inevitable that you inhale it unfortunately. Try to put as much distance, and if possible a barrier between you and the epicenter of where the smoke is coming from. A wet cloth over your nose and mouth is a good idea (not exactly good in front of friends though!). Otherwise wherever you visually see the secondhand smoke being blown out is where you don't want to be when you are inhaling. At least if it is not direct secondhand it can be so diluted that it doesn't build up as much of a blood level in your body perhaps. If it is your house then tell that person to buy a smokeless ash tray, open a window for ventilation, kick them outside! Best of luck.

EMT