Gas Mask - Reaction and Exchange

Reaction and Exchange

This principle relies on the fact that substances which can do harm to humans are usually more reactive than air. This method of separation will use some form of generally reactive substance (for example an acid) coating or supported by some solid material. An example is synthetic resins. These can be created with different groups of atoms (usually called functional groups) that exhibit different properties. Thus a resin can be tailored to a particular toxic group. When the reactive substance comes in contact with the resin, it will bond to it, removing it from the air stream. It may also exchange with a less harmful substance at this site.

Though it was crude, the hypo helmet was a stopgap measure for British troops in the trenches that offered at least some protection during a gas attack. As the months passed and the use of poison gas occurred more frequently, more sophisticated masks were developed and introduced. There are two main difficulties with gas mask design:

• The user may be exposed to many types of toxic material. Military personnel are especially prone to being exposed to a diverse range of toxic gases. However if the mask is for a particular use (such as the protection from a specific toxic material in a factory), then the design can be much simpler and the cost lower.

• The protection will wear off over time. Filters will clog up, substrates for absorption will fill up, and reactive filters will run out of reactive substance. This means that the user only has protection for a limited time, and then he must either replace the filter device in the mask, or use a new mask.

• A primitive respirator was designed by A. von Humboldt in 1799 for underground mining

• Various gas masks employed on the Western Front and Eastern Front during World War I

• Finnish civilian gas mask from 1939. These masks were distributed during World War II

• Iranian soldiers use gas masks during Iraq chemical attacks during the Iran-Iraq War