Air Purifiers Are they really good for us?
If you thought that the air purifier you recently bought protects you and your family from viruses and bacteria, you may be disappointed. A new and groundbreaking study published in the journal Annals of Internal Medicine reveals a worrying picture. There is a large gap between the marketing claims of manufacturers of air purification technologies and the actual scientific evidence.
A group of researchers from a medical campus in Colorado, working with the National Institute for Occupational Safety and Health and the Centers for Disease Control and Prevention, carried out an extensive review of nearly 700 studies published between 1929 and 2024. These studies looked at a variety of technologies, including HEPA filters, ultraviolet light, air ionizers and advanced ventilation systems aimed at reducing the spread of airborne respiratory illnesses.
The main finding showed that only 9 percent of the studies actually tested whether the use of these devices reduced illness among humans. Most of the studies were conducted in laboratory conditions or in controlled environments and not in real world settings such as homes, schools or offices.
In other words, rather than tracking an actual drop in infections, these studies looked at indirect measures like dust particle levels or various gases in the air. Many of these technologies sound impressive in theory, but we still don’t know if they really work in everyday conditions. People purchase and install these systems hoping to keep themselves and their families safe, yet the science hasn’t quite caught up with the marketing.
In addition to the lack of evidence on effectiveness, the researchers raised concerns about potential health risks from air purifiers. It turned out that only a small number of studies examined harmful byproducts that may form during the operation of these devices.
Some devices such as air ionizers and plasma based purifiers may produce ozone. Even at low concentrations ozone can irritate the lungs and worsen existing respiratory conditions especially in children and in people with chronic lung diseases.
The researchers argue that a new generation of studies is needed to test these technologies in real environments and follow actual cases of infection. Until then they recommend that consumers choose technologies that were independently tested and avoid products known to produce ozone.
Furthermore, they stress that traditional and long-established methods, such as proper ventilation, opening windows, and regular cleaning, remain the most reliable ways to maintain indoor air quality and limit the spread of infections. There is a reason why people say to air out the office to prevent the flu.