All living things need air and water to survive. There are a number of substances in the air that allow breathing to survive. However, there are also impurities and microorganisms in the form of particles of various sizes. They are either free in the air or depending on objects. Since air is ubiquitous, a microbial contamination in the air poses a risk to humans. The degree of this risk also varies depending on the density and diversity of the microorganisms. Therefore, the control of ambient air is an important issue.

Microbial control of ambient air is carried out using a number of devices. Microbiological measurements performed by laboratories provide more accurate results since the amount of air passing through the devices will be standard.

Bacteria hanging in the air harm humans and objects according to their variety and density. Especially bacterial spores are more risky because they can survive for a long time. Moisture of the environment, airflow, location of the building, structural properties and many factors affect the microbial load of the air. The concentration of mold in the ambient air is also dangerous for human health.

There are various systems used to measure the airborne microorganism load. Here are a few of them:

• Measurement of microbial load using test equipment
• Measurement of microbial load by open petri method
• Measurement of chemical components of microorganism cells
• Counting under microscope

There is no standard for indoor air density. Nevertheless, it is accepted that the total live bacteria and mold-yeast density in production areas is maximum 1000 cfu / m3.

Total microorganism load determination analyzes are performed in authorized laboratories within the scope of microbiology tests. In order to prove that they are reliable and impartial in these studies, laboratories are authorized by domestic or foreign accreditation grants. In the meantime, many published test criteria, test methods and standards are complied with.