This a tutorial on how to make a Redneck Special Ops gas mask. It has changeable filters, and you can change the type filter for your operation.

Step 1: Materials

you will need 2 bottles, a knife, duct tape, hose/tubing, respirator, and rubber bands.

There are many sizes of bottles. You will want to pick a bottle with little grooves and little bumps, to minimize distortion. Perhaps a 1.5 liter or bigger, but not too big!

Step 2: Cut!

Now you will cut a "t" shape in your bottle. Just follow the pictures.

Step 3: Tape!

This step requires to tape around the edges, creating an air tight seal. Plus it will relive the sharp pain from the sharp edges.
Tape around edges and bottom, so that the bottom curves towards your chest.

Step 4: Breathing Tube

Now for the breathing tube. This part is so that when you look down you don't suffocate. That is the only flaw of my design for using small bottles. hey, at least I'm honest.
First, you will need to get a decent sized tube, and drill a hole the same size as the tube in 2 caps.
Next, tape it until it is sealed around the sides.

Step 5: Filter

This is pretty simple.
First, take a bottle and cut off the top, and put a filter on the top.
Next, tape it down.
Make more if you will be using it often.