Portable air filters and HVAC filters can reduce indoor air pollutants, including viruses, found in the air. By themselves, these filters are not enough to protect people from the virus that causes COVID-19. However, HEPA filters can trap particles that contain coronavirus. People expel droplets of respiratory fluid, saliva, and possibly virus into the air when breathing, coughing, and talking. Even if the water in the droplet evaporates, the droplets contain salts, proteins, and other material in addition to any viruses, which means that the remaining particles are usually a few microns in size, making them quite easy to catch with a HEPA filter.HEPA stands for “high-efficiency particulate air”.
A HEPA filter can trap and remove microscopic particles, such as COVID-19 viruses, from the air. In that sense, a HEPA air filter can protect against COVID-19 from spreading to someone from an infected person. However, as noted by the EPA, it takes a multi-pronged approach to combating COVID and other viruses. One of their recommendations is to use air cleaners with at least a MERV 13 rating, or a higher HEPA rating when possible.
The Minimum Efficiency Report Value (MERV) is an effectiveness scale for air filters that was developed by ASHRAE in 1987. As the name suggests, these filters are very good for taking things out of the air and holding them so they can't circulate again. HEPA is the gold standard, but non-HEPA filters can help remove particles from indoor air.Many ventilation systems are not designed for HEPA, but these filters are available as portable air purifiers or vacuums. HEPA filters are the most efficient for residential or commercial use, followed by MERV 13-16 filters. Researchers have evaluated the ability of air filters to remove inactive particles in carefully controlled environments, but they don't know how they would work in a real world environment.
The most common appliances that use HEPA filters are portable air purifiers, vacuum cleaners, and heating, ventilation, and air conditioning systems, such as your oven. Professional opinion from an HVAC engineer is highly recommended before attempting to upgrade any air filter. These measures cannot be overlooked, even if you have the best air filtration and disinfection systems on the market.Addition of two HEPA air purifiers that met the Environmental Protection Agency (EPA) recommended Clean Air Delivery Rate (CADR) (reduced overall exposure to simulated exhaled aerosol particles by up to 65% without universal masking). This type of HEPA filter has a grade of H13-H14, which indicates that the filter can remove 99.95% to 99.995% of particles that are only 0.1 microns in size.
In addition to airplanes, these filters are used in operating rooms, other sterilized cleanrooms, indoor vacuums, air conditioners, refrigerators, masks, respirators and high-speed electric hand dryers to ensure that those small particles are trapped and not blown back into a person's hands after washing.Due to their particulate trapping qualities, HEPA air filters are an effective line of defense to combat the spread of COVID-19 indoors.