Air purifiers have received a lot of attention in the last year… and for good reason! Clean air can reduce allergy and asthma symptoms, help prevent heart and lung disease, and even lower the transmission rate of illnesses like COVID. But, not all purifiers are the same. Recent studies suggest that while most purifiers remove some pollutants from your air, ionizing purifiers may also be putting dangerous pollutants back into your home air.
How do ionizing purifiers work?
Ionizers, also known as negative ion generators, work by using high voltages to give an electrical charge (usually negative) to molecules in the air. These charged molecules are called ions. The ions are attracted to particles or surfaces with the opposite charge, causing them to clump together into larger heavier particles that fall out of the air or get stuck to charged surfaces like curtains.
How effective are ionizing purifiers?
Not very. A summary of scientific tests of air purifiers found that most ionizers used in homes have no noticeable effect on particulate levels. While there are some stronger ionizers that can be more effective, they are rarely available for general purchase.
But, can ionizing purifiers eliminate COVID?
In recent months these ionizers have become popular because of their so-called “virus-killing” ability. Some manufacturers have even gone so far as to claim that the devices are able to remove 99 percent of viruses. In fact, several aggressive advertising campaigns were launched to try to label ionizers as an essential tool in combatting COVID.
Unfortunately, the truth about ionizers is that they don’t actually remove COVID or other germs. What they can do is create static charges on airborne particles, making them “stick” to other things. This means that virus-laden particles end up on surfaces like walls, counters, and faucets. So instead of removing COVID, they just relocate it to surfaces that still require disinfecting.
What do we know about the negative effects of ionizing purifiers?
A recent study, authored by researchers at Illinois Tech, Portland State University, and Colorado State University noted that inadequate test standards, confusing terminology, and a lack of peer-reviewed studies of the effectiveness and safety of ionizing purifiers have misled consumers about the potential dangers of ionizing purifiers.
One concern that the study revealed was that, while ionizing purifiers eliminate some volatile organic compounds (VOCs), they actually increase the presence of other VOCs, particularly oxygenated VOCs (e.g., acetone, ethanol) and toluene, substances commonly found in paints, paint strippers, aerosol sprays and pesticides.
This may be because ionizers work by “adding” ions which can react with other compounds in indoor air, leading to the formation of byproducts such as formaldehyde and ozone.
And it isn’t just VOCs that can be created. The study also noted the danger that ions can bind to other gases and create new ‘ultrafine’ particles.
What’s so harmful about VOCs and ultrafine particles?
VOCs are a combination of gases and odors emitted from a variety of everyday products. Short-term exposure to VOCs can cause headaches, respiratory irritation, nausea, lack of coordination, and excessive fatigue. The longer-term effects of VOCs in humans have not yet been fully studied, but VOCs have been found to cause cancer in animals.
PM2.5, along with even tinier ultrafine particles are composed of a mixture of solid and liquid particles that are suspended in the air. PM2.5 particles are easily inhaled and are able to penetrate deep into your respiratory system.
Exposure to PM2.5 has multiple short-term and long-term health impacts. Short-term issues include eye, nose, and throat irritation, coughing, sneezing, and shortness of breath. Long-term exposure to PM2.5 can cause permanent respiratory problems such as asthma, chronic bronchitis, and heart disease.
While PM2.5 impacts everyone, people with breathing and heart problems, children, and the elderly are most sensitive to it. One recent study called PM 2.5 “the largest environmental risk factor worldwide,” responsible for many more deaths than alcohol use, physical inactivity, or high sodium intake.
How are ionizing purifiers generally tested?
Brent Stephens, Chair of the Department of Civil, Architectural, and Environmental Engineering at Illinois Tech noted that manufacturers commonly test their product’s effectiveness using chamber tests. The problem is that these types of reports often don’t show how the device actually performs in real-world conditions. Stephens said that most of the current industry-led standards focus on ensuring that ozone isn’t generated, neglecting the other harmful contaminants that may be present.
How did the new study test ionizing purifiers?
Rather than using chamber tests, the new study, published in Building and Environment, mimicked real-world operating conditions to see how these purifiers work in environments similar to where we all live, work, and learn. The research team found that despite small changes in particle concentrations, there was very little net effect on the overall concentration of PM2.5 in the air.
Have any other tests shown problematic results for ionizing purifier usage?
Unfortunately, other tests have confirmed the dangers of ionizing purifiers. In August 2020, a study showed that exposure to negative ions was associated with increased systemic oxidative stress levels (a marker of cardiovascular health). It also showed that, while there was a reduction in indoor particle concentrations, there was no improvement in respiratory health.
Another recent study of air ionizers in school classrooms showed that, while ionizing purifiers did seem to result in some improvements in respiratory health among 11-to 14-year-old children, the ionizers also seemed to cause heart issues in many of the children.
Is there a better option?
Yes! A purifier with a True HEPA filter can safely eliminate 99.95% of harmful particles, without adding anything harmful to your indoor air.
Although the standard for HEPA filters is that they need to be able to filter out 99.95% or more of all particles which are 0.3 microns in diameter, they are actually capable of filtering out particles of almost any size. A True HEPA filter can trap dust, smoke, pet allergens, PM2.5 (dangerous particles that are 2.5 microns or smaller).
To remove both particles and harmful gases from your indoor air, look for a purifier that combines uses both True HEPA and activated carbon filters.