We recommend air purifiers with a HEPA filter; HEPA stands for high-efficiency particulate air, says Dr. Standalone air purifiers are designed for a single room, so you should use them with the door closed and check that your air filter fits the size of the room. Research experts fear that electronic air filters (including the last two types of air filters on this list) may produce ozone gas and other contaminants that may be hazardous to health. Therefore, air purifiers with filters are considered to be the safest for home use.
Golden said that complaints must also be evaluated with reservations. Air cleaning devices, such as air purifiers, help improve indoor air quality by eliminating or reducing contaminants and allergens. These substances can worsen the symptoms of allergies or asthma. They can also contribute to more serious lung diseases and even to certain types of cancer. It all depends on what you want an air purifier to do in your home and how well you adapt the specific air purifier to your objectives.
Do-it-yourself air purifiers are indoor air filters that can be assembled with box fans and square HVAC (or oven) filters. You can also search for air filters and purifiers that are certified as suitable devices for asthma and allergies by the Asthma and Allergy Foundation of America. Portable air purifiers are good for helping to ventilate the house, reduce or increase humidity, limit access to air pollution, and generally keep the air in the house clean. For people with allergies, scientific studies have shown that air filtration reduces these airborne allergens and may provide some relief. When used in conjunction with other practices recommended by CDC and other public health agencies, such as social distancing and the use of masks, filtration can be part of a plan to reduce the chance of airborne transmission of COVID-19 indoors.
Portable air filters (also known as air purifiers) can be particularly useful when it is not possible to obtain additional ventilation with outside air without compromising indoor comfort (temperature or humidity) or when outdoor air pollution is high. The best option for filtering particles is a device with a HEPA filter, designed to collect at least 99.5% of airborne particles that are 3 microns in size or less. Using a home air filter that wasn't properly designed or assembled doesn't worsen indoor air quality and may still offer some benefits. Air purifiers can help clean the air in your home from unwanted particles, such as pet dander, allergens, and smoke.
The use of air filters alone cannot guarantee adequate air quality, especially when there are significant sources of contaminants and ventilation is insufficient. To address concerns that box fans in home air purifiers may be related to an increased risk of fire, the EPA and Underwriter Laboratories evaluated the use of household air filters and the risk of fire. This makes air purifiers useful during short-term smoke produced indoors by forest fires, but they are not fully effective in protecting health from the adverse effects of tobacco smoke, whether primary or secondary. Having an air purifier at home doesn't have many drawbacks aside from financial investment.
For an air purifier to be effective at removing viruses from the air, it must be able to remove small particles suspended in the air (in a size range of 0.1 to 1 um). Consult ASHRAE and CDC for more information on air cleaning and filtration and other important engineering controls.