There are many models to choose from, each with different functionalities and protection levels.

Respirators are easy to find in big-box stores and offer protection against noxious gases as well as particulates.

Escape Hoods Single-Use Masks that can be used to escape from a burning building. They last anywhere from 15 to an hour.

Full Face Gas Masks or NBC masks stands for Nuclear, Biological, and Chemical. CBRN stands for Chemical, Biological Radiological, and Nuclear.

There are many good respirators and gas masks available online on Gas Mask Pro.

We are getting warmer here. Some respirators don't cover your face and could pose a problem if you are exposed to severe conditions. When someone else buys one, escape hoods can be cool. These can be quite expensive. They are an excellent investment if you live in a high-rise building, especially if your children are involved.

Dust masks are inexpensive and easy to locate. They can be used for dust removal or light construction.

Surgical masks are designed to keep blood out of the wearer's mouth or prevent the doctor from spreading germs to a patient.

Which of these masks is most useful? While there are some strong dust masks worth considering, surgical masks will not adequately protect your lungs.

Now we're getting to the good stuff. This is about as serious as you can get without having a scuba tank on your back. If your funds allow it, this is where you want to wind up: with a high-quality mask and lots of filters to go along with it.

The concept of a protective mask against chemical assault dates back over 500 decades, to Leonardo da Vinci (Smart, 1997).  From the mid-nineteenth century, protective masks were proposed in the United States and Europe for both military and industrial use. 

The modern gas mask was developed by the Germans with sodium thiosulfate- and bicarbonate-soaked pads, and it was used during World War I (Joy, 1997).  The English and French soon followed with their own variations of gas masks (Joy, 1997).  You can check out this link to find different types of gas mask available today.

In 1916, the Germans introduced a mask that incorporated a canister through which the soldiers breathed (Joy, 1997).  Initially, the American forces in World War I utilized gas masks obtained from allies fighting in the war (Smart, 1997).  In 1918, the Americans introduced Richardson, Flory, and Kops (RFK) mask, a modified variant of the British mask.

Moreover, masks were developed for the animals, such as horses, that supported the war efforts.  Decontamination efforts during World War I were rudimentary and included chemical neutralization and aeration of clothes and gear.  Even though the need to find chemical agents was clearly identified, hardly any progress was made during World War I.