Particles in the air can range in size from very large to extremely small. The size of a particle can determine how it behaves in the air and how it can affect our health. Understanding particle sizes and how different types of filters can remove them can be important for protecting ourselves and others from harmful airborne pathogens.

Particle sizes are often measured in micrometers (μm), which are one millionth of a meter. Particles that are larger than 10 μm in size are generally visible to the naked eye and are referred to as “coarse” particles. These particles include things like dust, dirt, and pollen. Particles that are smaller than 10 μm but larger than 2.5 μm are referred to as “fine” particles. Fine particles include things like smoke and haze. Particles that are smaller than 2.5 μm in size are referred to as “ultrafine” particles. Ultrafine particles are so small that they can be inhaled deep into the lungs and can cause serious health problems.

There are several types of filters that can be used to remove particles from the air. These filters can be classified based on the size of particles they are able to remove.

Coarse particle filters: Coarse particle filters are designed to remove large particles from the air. These filters are often made of fiberglass or another type of synthetic material and can be used in air purifiers or HVAC systems. Coarse particle filters are not very effective at removing fine or ultrafine particles.

Fine particle filters: Fine particle filters are designed to remove small to medium-sized particles from the air. These filters are often made of fibers that are tightly woven together and can be used in air purifiers or HVAC systems. Fine particle filters are effective at removing particles like smoke, haze, and certain types of bacteria.

Ultrafine particle filters: Ultrafine particle filters are designed to remove very small particles from the air. These filters are usually made of materials like HEPA (high-efficiency particulate air) or ULPA (ultra-low particulate air) and can be used in air purifiers or HVAC systems. 

UV filters: UV filters use ultraviolet light to kill or inactivate harmful particles in the air. These filters are often used in hospitals and other settings where it is important to destroy or inactivate harmful pathogens. UV filters are extremely effective at removing and inactivating certain types of bacteria and viruses, but they are not effective at removing larger particles like dust and dirt.

Ozone filters: Ozone filters use ozone gas to destroy or inactivate harmful particles in the air. These filters are not commonly used due to concerns about the potential health effects of ozone gas. Ozone filters can be effective at removing certain types of bacteria and viruses, but they are not effective at removing larger particles like dust and dirt. 

The type of filter you choose will depend on the size of the particles you want to remove and the specific needs of your application. If you are looking to remove large particles like dust and dirt, a coarse particle filter may be sufficient. If you are looking to remove small to medium-sized particles like smoke and haze, a fine particle filter may be a good choice. If you are looking to remove very small particles like some harmful pathogens and certain types of bacteria, an ultrafine particle filter like a HEPA filter may be the best option. If you are looking to destroy or inactivate specific types of harmful viruses, a UV filter may be the way to go.

The patent pending Rejuvenair system uses a combination of HEPA and the only UV filters approved for use by the Infection Prevention Society, which when combined are extremely effective in the deactivation and/or removal of pollen, dust, moulds, bacteria, smoke and viruses in business environments. Moreover, it informs you about the quality of your indoor air in real time via smart app which also lets you know if there’s a problem and keeps us and you in the loop with maintenance scheduling. If you would like to find out more about Rejuvenair, email us at contact@rejuvenair.co.uk.