Air is a carrier of particulate matter, dust or droplets which may be laden with microbes. Organisms introduced into the air, can survive for many months or die in a few of seconds, in relation to the resistance of species to the new phisical environment.
Airborne microbes constitute a hazard as contamination to laboratory and home. There are several devices to effect the sampling of air. There are solid and liquid impingement devices. In solid impingement devices, microbes are impinged on the solid surface of an agar or filter disk. Then, they are passed through a liquid as a broth. Finally, aliquots of liquid are cultured to determine their microbial content.
The numbers and types of microbes contaminating the air are determinated by the source of contamination. Organisms contained in the air above the ocean and those contained in the flora of the upper atmosphere are capable of surviving to temperature and humidity changes and to a solar radiations.
Microbiologists are concerned with the fact that all laboratory tecniques produce aerosols. If the microbe under study is a pathogen, there will be a hazard to laboratory workers, which can acquired infections.
Air hygiene is of great importance because some infections agents can be airborne. Certain operations require that air be sterile, such as the air contained in a culture tube. There are industrial processes that require organisms grown in a pure colture under aerobic conditions. The level of air contamination can be reduced or sterilized as the situation demands.