Air Filters

The field of air purifiers and air filters is a very confusing one for the average person. Purifying air involves removing contaminants from the air. However there are contaminants in the form of physical particles as well as contaminants in the form of gas or vapours. These different forms of contaminants require different types of filter media. Most air purifiers will have a HEPA (high efficiency particulate air) filter for particles and activated carbon for gases. There are very few filters that have a highly efficient photo-catalytic filter which will break down particulates on a molecular level. This is essential as it is the most efficient way of effectively filtering out the very small ultra-fine particles. It is also essential that the air purifier has at least 3 UV (ultra-violet) lamps that will effectively kill the bacteria. The smell that many vacuum cleaners emit is often due to the build up of bacteria on the filter.

Decisions are often made about air filters based on the area that the air purifier can clean. A defined area is often quoted as this is information that is often requested. However this figure can be misleading and should not be used for comparison and relied upon. This is due to the fact that if the air is more polluted then the air purifier will not clean the area quoted. If the air contains certain types of pollutants it may not be as effective. The air in which the air purifier is quoted as being effective varies depending on the amount and type of contaminants present. Humidity, pressure and temperature also play a role in influencing the effectiveness of the purifier and this is why the quality of the filter media is more important than the figure quoted as being the area that the purifier will clean.

The effectiveness of ionisers is also a common query. There is no question that negative ions are beneficial for our well being but there is some controversy in connection with man made AC produced negative ions as opposed to those naturally produced ( DC ) in nature. The negative ions produced by some air purifiers will clean the air in that particles stick to the negative ions and then settle on a surface. This does however sometimes make walls and other surfaces quite dirty but it is better to have these pollutants on surfaces rather than in our breathing zone.

With all aspects considered as a Building Biologist the air purifier recommended can be obtained by clicking on the air purifier link.