Air purifiers are becoming increasingly popular in many households. They can contribute a lot to the quality of the air circulating through the owner’s home, and most models are relatively inexpensive and low-maintenance. There are several different methods commonly used for air purification, all of which have their advantages and disadvantages.
A common question that many users have been asking over the last two years is whether air purifiers do anything to help prevent the spread of COVID-19. Buyers who’re primarily interested in air disinfection should pay close attention to what they’re investing in. Some air purifiers do very little to help with microorganisms like viruses and bacteria.
How Do Air Purifiers Work?
The most popular approaches to air purification on the consumer market right now include HEPA filters, activated carbon, and ionization. UV light is also used in some devices, though it’s less popular than other solutions at the moment.
HEPA air purifiers are the most basic. They work by forcing air through a HEPA filter, which is designed to capture small particles, trapping them permanently. HEPA filters are great for particles larger or smaller than 0.3 microns. While they can also capture particles around that size, their performance usually declines noticeably in that area. Airborne Coronavirus particles get trapped by HEPA filters, but they are not deactivated or killed.
Activated carbon purifiers work in a similar manner. The main difference is the method of filtration. Instead of a HEPA filter, activated carbon filters are used instead. The porous nature of the material makes it ideal for trapping particles and microorganisms. It’s often recommended to use a HEPA filter in combination with activated carbon filters to increase the overall purification rate inside the household.
Air ionizers charge particles passing through the device, relying on electrostatic attraction to trap them inside the purification unit. In some cases, charged particles are released back into the air, allowing them to fall freely on the ground. This is less common in modern devices.
Finally, UV air purifiers operate by exposing the air to ultraviolet light. This scrambles the DNA of most microorganisms, effectively killing them. UV purification is often used for treating water but is also a popular solution for air sterilization. Its effectiveness tends to decline in dusty environments with a high amount of particles floating in the air. Those particles create shadows that block UV light, preventing it from hitting all microorganisms that pass through the purifier.
How Does COVID-19 Spread?
COVID-19 is transmitted through airborne particles and droplets. While the virus doesn’t remain active for long once it becomes airborne, it can still spread rapidly in enclosed environments with poor circulation. Inhalation of particles and droplets is the most common cause of becoming infected. The virus can also spread through hard surfaces, particularly ones that people frequently touch, like door handles and elevator buttons.
Improving air circulation has emerged as one of the best preventative measures against the spread of COVID-19 indoors. This can be accomplished by either allowing more air to enter/exit the environment (by keeping more doors and windows open), or by increasing the rate of internal circulation with ventilators, air conditioners, and air purifiers.
Additionally, disinfection of surfaces around the areas where air passes through can reduce the number of virus particles in the air. However, this may not always be possible due to the layout of the building.
Are Air Purifiers Effective Against Coronavirus?
Some types of air purifiers can contribute to preventing the spread of COVID-19. HEPA filters in particular are highly effective due to their ability to trap small particles at a consistent, high rate. However, filters need to be frequently cleaned and/or swapped out to minimize the risk of particles lingering after being captured. Additional filtration, such as the use of activated carbon filters, is also recommended for optimal effect.
Around a year after the COVID-19 pandemic started, some concerning research results emerged, suggesting that air purifiers could theoretically increase the spread of the virus in some specific cases. Specifically, researchers claimed that increasing air circulation in confined spaces could promote the distribution of virus-containing droplets and particles.
However, these results were only theoretical and were later contradicted by the results of practical experiments. For now, the general consensus remains that air purifiers don’t contribute much to the spread of COVID-19 (neither positively nor negatively). Buyers concerned with minimizing the spread of the virus are advised to investigate additional filtration solutions. An air purifier can still help improve air circulation and trap free-floating particles, which can increase the efficiency of other filtration methods, especially UV sterilization.
Tips for Keeping the Air in Your Home Safe
Maintaining a safe and healthy environment at home in the current pandemic mostly comes down to improving air circulation and regularly cleaning entry/exit points. Homeowners are advised to air out all rooms in their homes at least once a day, ideally twice for rooms that are actively used.
For the best results, windows should be opened at the highest and lowest points of the home. This will maximize airflow and reduce the time needed for airing rooms. Fans can also be used for additional circulation, though they are not necessary when enough windows are available.
When an HVAC system is available, it should be run for longer durations on a regular basis. Any filters used in the system should be replaced frequently, ideally more often than in normal circumstances. It’s important to note that some filters can’t be cleaned without risking damage, requiring a complete replacement.
Windows, doors, and other points through which air enters and exits the household should be cleaned and disinfected regularly. This includes air conditioners, purifiers, and any other devices that process the air in the household.
A portable air purifier can be a good solution in situations where different parts of the home are utilized during different times of the day. Whenever possible, users should attempt to schedule the relocation of the purifier so that it can operate for at least 20-30 minutes before the room is occupied.