Infectious diseases caused by airborne viruses and bacteria are a major problem for both economic and social reasons. To eliminate the health risks caused due to particles or pollutants present in the air, air filters came into existence. The first air filter came into existence in 1848. It was launched by Lewis P. Haslett with the use of charcoal filters. There was a need to clean air contaminated with radioactive particles which was fulfilled with the introduction of HEPA filters in 1940. It was developed by the US Atomic Energy Commission and was released to the public after World War II.
In the 1960s, a German engineer and his brother innovated a simple air filter system that used magnets to attach the air filters and was made up of a filter pad. In the 1990s the first room air purifier IQAir HealthPro Plus came into existence. This room purifier was developed by Frank and his team of engineers from Germany and Switzerland. Currently, HEPA purifiers rule the air filter market as they remove very tiny particles from the air stream that passes through them and are a great help for people with asthma, allergies, or those who suffer from respiratory problems.
What are Air Filters?
Air filters are appliances that are embedded with several layers of permeable and fibrous materials used to remove pollutants, airborne particles, and microorganisms from ecosystems that are hazardous to health. It also removes odors and gaseous pollutants such as volatile organic compounds or ozone.
What are the Types of Air Filters?
Air filters are utilized for capturing or filtering displeasing particles and pollutants from circulating in the air. It consists of a microscopic perforation or a single piece of synthetic fiber. Air filters can be further classified as:
- Pre Filters: A pre-filter is an essential part of almost every air filter. It essentially helps to capture large particles and it is the first stage of filtration. Pre-filters prolong the life of the filter, and it makes the system much more efficient.
- HEPA Filters: HEPA refers to high-efficiency particulate air. HEPA filters are pleated with mechanical air filters that have a considerable thickness to capture the particulates. It removes 99.97% – 99.99% of airborne particles that are smaller, larger, or equal to 0.3 microns in size. Recently, Dyson launched two new air purifiers in India with HEPA 13 standard filtration, which can remove 99.95% of particles as small as 0.1 microns.
- ULPA Filters: ULPA filters are a great help at removing submicron particulate matter of 0.12-micron diameter and are 99.999% effective. ULPA filters are only necessary for specialized applicsations such as medical laboratories or microelectronics manufacturing. ULPA filters are used in removing air particulates from surgical rooms such as filtering toxic surgical plumes. The life cycle of a ULPA filter ranges from 5 to 8 years.
How Air Filters Work?
As the air passes through, air filters capture contaminants and particles from the air. Particles that pass through the air filter are caught by three mechanisms: straining, interception, and diffusion.
- Straining: Straining filters out big particles typically larger than 10 microns. Large particles fly into a filter and get stuck as they are too big to get through. When particles get stuck between two fibers, scientists call it straining.
- Interception: Interception filters out small particles such as bacteria whose size ranges between 0.3 to 1 micron. These particles get stuck as they are a bit heavy which makes them don’t move fast enough and end up getting stuck.
- Diffusion: Diffusion filters out very small particles less than 0.3 microns. These particles get stuck and end up hitting the fibers as they move in random zigzag patterns due to the little mass.
Conclusion
Air filters are devices to remove smoke, dirt, dust, viruses, aerosols, odors, molds, bacteria, toxic gases, and other particles that exist in ambient air. These airborne particles and pollutants are hazardous to the ecosystem and health. Air Filters come in various types such as Pre-filter, HEPA filters, ULPA Filters, and others. HEPA filters are currently widely used as they capture at least 99.97% of particulates of size measuring 0.3 microns in diameter. The air filter uses three different mechanisms to filter out particles from the air. The need for air filters is growing with an increase in population and pollution in air.
