Can a Gas Mask/Respirator protect you from Smoke?

I frequently get asked, can a gas mask or respirator protect the wearer from smoke, from both wild fires and house fires. The answer is a little complicated. Respirators with particulate filters can block smoke and respirators with chemical vapour filters can block hazardous fumes from fires, a combination filter can protect the wearer from both but no gas mask with filters can give the wearer oxygen or decent protection from carbon monoxide. A supplied air respirator or rebreather would be needed in an ar