An important component of environmental control measures is the use of filters in the air
conditioning and heating units and in air purifiers. Such measures remove suspended particles from the indoor air. A variety of filters are available for this purpose; physical coarse and fine filters, electrostatic precipitators and other more exotic types of dust catchers that use ions are available in many commercially available air purifiers. The most efficient of the air purifiers use a combination of the above in succession and a final layer of activated charcoal and is called a "HEPA" filter. The abbreviation stands for "high efficiency particle accumulator" and a variety of air purifiers have this filter as the active ingredient. In these, the dirty air is sucked into the unit, passed through the filter and the clean air pushed out with almost 99.5% of particulate matter cleared from it. This assures removal of mold spores, house dust mite fragments, pollens and to a smaller extent the fumes and other fine pollutants.
There are now numerous air purifier units commercially available, with little to choose between
them. You should have a good idea about the measurements of the room to be cleaned as the
efficiency of the units will definitely be affected by the volume of air to be moved through the unit per minute. The bed room and the living room are the most important rooms for installing the HEPA air Purifiers. Ideally the unit should be started an hour or so before one retires (obviously, the bed room unit) and kept running through the night.
One point that definitely needs to be stressed is the use of these or any other form of air
purification system will fail if sensible other measures are also not taken at the same time. Good examples are removing pet animals such as cuts and dogs from indoors, discontinuing feather pillows and down comforters and tackling mold growth-promoting leaks in the ceilings and walls. An important but little understood but extremely common roblem in many homes is the ceilings and walls. An important but little understood but extremely common problem in many homes is the use of humidifiers. If the ambient air is more than 40% humid, attempting to humidify the room is fool-hardy! This will definitely worsen the patient's condition at least in the long term.