Bacteria in the Air

Dust mite allergies

Airborne bacteria (and viruses) are a common source of respiratory infection and a particular threat to infants, the elderly and those with compromised immune or cardiovascular systems, including people with allergies, asthma, AIDS and heart disease.

Some serious infectious diseases are spread by these biological organisms include whooping cough, meningitis, pneumonia, tuberculosis, diphtheria, cholera, scarlet fever and anthrax.

These high-threatening organisms range in size from .18 microns to as large as 1.325 microns. Air purifiers can provide some protection catching airborne particles as small as .3 microns with a HEPA filter; however these living organisms may not behave in exactly the same way as non-living particles in the context of filtration making it difficult to say that all organisms passing through the filter will be captured.

Some pathogens can move on their own, and some have slimy coatings that may affect a filter's ability to capture them.


Air often contains tiny organisms such as fungi, bacteria, mycotoxins and viruses.

None of these microorganisms live in the air but they are often attached to other small particles such as water droplets, soil or skin flakes, clumping together in small groups enhancing survival while airborne.

There are approximately ten times as many biological organisms as human cells in the human body, with large numbers on the skin and in the digestive tract.

The existence of microorganisms was hypothesized during the late Middle Ages and was first observed in 1676 using a single-lens microscope by Anton van Leeuwenhoek.


Vital in recycling nutrients and many important steps in nutrient cycles, we are dependent on these microorganisms, such as the fixation of nitrogen from the atmosphere. Life depends on these tiny microorganisms.

However, when they form a parasitic association with other organisms they are classed as pathogens which can be extremely toxic to human life as a major cause of human infections, disease and even death.

Most of these microorganisms have not been characterized and only about half have known species which can be cultured in the laboratory at this time.

Bacteria are single celled microorganisms that lack a nuclear membrane. While it is perhaps easy to think of them as simple forms of life, the truth of the matter is that they are highly adaptable.

Their normally rapid reproduction rate (by binary fission) and high capacity for spontaneous mutation allows them to respond to changing environments readily. This has made them ubiquitous in the biosphere, both as free-living forms and as parasites in multi-cellular forms of life.

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