If you live or work in a place that has a particularly high count of particulate contaminants in the air that are hard or impossible to get rid of, especially if you have an allergy or a respiratory condition, you should look into protective respirators, which come in many shapes and kinds, and are quite effective at protecting the wearer from potentially harmful dust particles. Respirators can generally be categorized as two kinds: there are air purifying respirators, which filter the air that the person inhales, as well as air supplied respirators, which provide an alternative air supply that has little or no contaminants in it.
Protective respirators have been in use for about two centuries, and they proved themselves particularly useful on a mass scale in World War I, when the combatants used lethal gas as a weapon–respirators protect against dust as well as many poisonous gases and other harmful materials that can be found in the air. Respirators can be simple, cheap and designed for one-time use, but there are also more complex powered respirators that can be reused and generally provide better protection. The best respirators, which have filters that meet the HEPA standard (see “Air Purification”), can filter up to 99.97% of all contaminants in the air.
There are also powered air purifying respirators, which actively remove dust and other harmful particles or gases from the air supplied to the wearer, as well as self-contained breathing apparatuses, which include a tank of clean air supply. Respirator design can be varied as well; some respirators are full face masks, while others are half-face. For simpler purposes, for example to protect yourself against exposure to domestic dust while cleaning your house, a simple respirator with a good filter should do the job fine. Buying a reusable respirator can be an especially good investment if you have a previous respiratory condition, are allergic to dust, or if you live in a crowded city with a high concentration of particulate matter in the air.