· Gas mask filters have a limited life-span. Most of them have just a few hours of active use (depending on the amount of dangerous substance being filtered and the relative air humidity). At this point the filter needs to be changed. Never buy a second-hand mask as you will not know how much life the filter has left in it.

· You'll need precise instructions on using your gas mask. There's more to it than just pulling it over your face. Inappropriate use may be more dangerous than the substance you're trying to protect yourself against. Ideally you should get some training on the correct use of gas masks and both you and your family should practice using them regularly.

· You should be clean-shaven when putting on your gas mask. A beard (or even stubble) may enable the poisons to infiltrate the mask.

· If you've had no training in the use of gas masks, there's one important point to remember - take the plastic seal off the filter before putting the mask on. During Operation Desert Storm (1990) eight people lost their lives because they forgot to remove the seal (they thought they were being poisoned, when in fact it was the mask that was smothering them).

· Some gas mask filters have larger intake openings designed for people with lung/breathing problems.

Increasingly, gas masks are available in various sizes - even for children and babies. If you're buying gas masks for your family, then be sure that each one has a perfect fit. Some masks are equipped with drinking systems, and masks that enable easier speech (via 'voice-mitter') are also available.

· Don't buy masks via mail-order or over the Internet as you can't be sure that they'll fit properly. Always buy them in person from a professional who knows what he/she is talking about. Be sure to get a mask fitted for everyone in the family. To my knowledge, there are currently no gas masks available for pets...

· Bear in mind that, while gas masks are effective against most chemical and biological agents, they do not assure protection against everything. Be sure to get a gas mask that is certified to be effective against chemical and biological weapons agents.


· Generally, for biological agents to be effective, they need to be between 1 and 5 microns in diameter. For this reason, regular surgical masks, which are relatively cheap, would protect you against almost all biological threats. Protection against chemical agents, however, requires a gas mask.

· If you have a baby or a young infant who is reluctant to put on a gas mask during an attack, then don't waste time struggling. Strive instead, to get both yourself and the child to a safe place as quickly as possible. It's for this reason also, that it's vital that you practice proper gas mask usage with your family -- particularly young children.