When you think of air pollution, the very last place you expect to see it is in your family's house. However, according to the U.S. Environmental Protection Agency, indoor air pollution may very well be 2 to five times higher - and at times more than 100 times higher - than outdoor levels. That means unacceptable indoor air quality is one of the top risks to our health. Since a good number of us spend 90% of our time inside our homes and offices, that's disconcerting.

HEPA (High Efficiency Particulate Arresting) filters are one strategy for better indoor air quality. HEPA filter technologies have been used since the 1950s when the US Atomic Energy Commission thought it was important to eradicate tiny radioactive particulates from the air.

HEPA filters work along these lines: think about one sheet of HEPA paper (really it's made of a paper-like fiber or polymer) with very tiny holes that filter out contaminating particles. Owing to the fact that the surface area is restricted, only tiny amounts of air are able to flow through. If the size of the sheet was doubled, it would be possible to get two times the airflow and twice the filter life.

A larger surface area would definitely cause a more productive filter. So instead of increasing the dimensions of the sheet itself, the surface area is increased by being folded back and forth quite a few times. Some filters have as much as 40 square feet of filter material. HEPA material is actually a rather impressively thin bond of fibers.

Air is forced to go through this complicated network of fibers and in the process, the polluting particles hit the fibers and stick. HEPA filters naturally filter out bigger particles like dust, however they also work efficiently against mold spores, viruses and bacteria.

Many types of air purifiers insist that they clean 99.97% of the air that flows through the HEPA filter - but what they don't reveal is that some air doesn't flow through the filter. If the air doesn't go through the HEPA filter then certainly it isn't filtered. That makes the issue of 99.97% efficiency questionable.

The best quality HEPA filters don't have a problem in this particular area because their designs include fans that really push air through the filter - the more air that flows through the filters, the healthier and cleaner the air becomes.

The size of the room is a key consideration when determining the size the air purifier should be. Evidently the bigger the room is, the larger the filter ought to be. Another possible idea is to have 2 smaller filters. They can divide up the work - and allow twice the amount air to make it through the filter.

Be advised that HEPA filters do not filter out odors, chemicals and gasses. That's because these molecules are much too tiny compared to HEPA's 0.3 micron holes. In order to filter out these destructive molecules, some type of substance is important to absorb them - activated carbon is commonly used.

Take time to ask questions when it comes to making a decision about which air filter to get for your family's health. Knowledgeable store owners know about their brands and can best suggest which size of filter is necessary to guard your home and ensure it's healthy and clean.

Discover invaluable information about how to make your home safer and more comfortable for your family. Karen Naylor offers tips and tricks to help you make the best decisions about affordable window blinds, affordable window shutters and best window treatments