Filtering has an important degree of success, with 99.9% efficiency using HEPA (High Efficiency Particle Arresting) filters. These filters could retain particles with diameters lower than 0.5 micrometers using fiberglass lattices. In planes, thanks to HEPA filters, the levels of bacteria and fungus are lowered toward safe levels.
With ultraviolet radiation it's possible to induce a germicide action although there's a chance for the creation of ozone. In these conditions, a HEPA filter is recommended.
Another standard is activated carbon because its crystalline composition retains different types of particles. It's newly recommended employing a HEPA filter if the air includes particles that the activated carbon will not catch.
The air could include solid and liquid particles with different size. Vapors and gases, with a specific type of purifier for them. There's the risk of using an unappropriated technology and then, the issue would continue without solution. Before making investments on air purification, the user should be completely sure of the air composition in any potential condition.