If you're planning on protesting here are some tips on how to deal with tear gas. From Medic Wiki at http://medic.wikia.com/wiki/Pepper_spray_and_tear_gas.
Some great resources on street medic training and dealing with tear gas and pepper spray.
To everyone protesting in Ferguson, stay safe and don't give up the struggle for justice!
(Archive photo from http://upload.wikimedia.org/wikipedia/commons/7/76/Ferguson_Day_6,_Picture_44.png)