The scientific description of a catalyst is any substance that can be used to increase the speed of a chemical reaction, but is not consumed in the process. One of the reasons that gold has become a very popular and useful catalyst is that is has a very low "light off" temperature. This is the temperature at which the catalyst becomes activated. This low activation temperature makes gold an ideal catalyst for a wide variety of applications. Most other materials would not be suitable for use because of the higher reaction temperatures. One of the most important uses belongs to the brave men and women of the thousands of fire departments around the world and to those who go underground to mine the coal we use to provide the power and heat for our homes. Often these men and women must work in conditions that involve being exposed to high levels of carbon monoxide.

Conditions such as fires and working around machinery such as boilers that consume all or most of the oxygen in an area and leave nothing to breathe except carbon monoxide require a way to remove this from the air and allow the person to breathe. Special respirators have been designed that incorporate gold into the filters. When subject to warm room temperatures the gold acts as a catalyst that reacts with the other elements contained in the filter to remove sufficient carbon monoxide from the air. This will allow the person wearing the respirator to breathe safely while performing their job, without the need to wear a cumbersome self-contained breathing apparatus. Respirators are not the only place where gold is used as a catalyst to clear the air. These gold infused filters are used in offices, workshops and industrial settings as well as certain types of vehicle. They are designed to help remove carbon monoxide and many foul smelling compounds such as trimethylamine that contain nitrogen.

They are used to improve the overall air quality and control the odors that may be produced as the result of normal day to day operations. There are many other areas that make use of these filters due to the limited amount of space for the occupants or the overall environment. This includes military submarines, space craft and office buildings where large numbers of people work. Filters like this can also be used in areas where a percentage of those who live or work still insist on smoking cigarettes to remove the carbon monoxide and various nitrogen compounds from the air, making it significantly more healthy and better smelling than it might otherwise be.