When you think of air pollution, you probably think of clouds of pollution rising out of smokestacks, and smog from car exhaust. But if you’re a typical 21st century person, you spend about nine out of every 10 hours indoors—and the U.S. Environmental Protection Agency has stated that indoor air in cities can be up to 100 times more polluted than outdoor air.
There are many types of indoor air pollution, including biological pollutants like mold, mildew, dander, and pollen; chemical pollutants like radon and carbon monoxide; particulate matter like dust and smoke; and microplastics. As we learned during the pandemic, even viruses can be a threat to indoor air quality.
The most common type of indoor air pollution is volatile organic compounds (VOCs) that “gas out” from indoor paints, varnishes, adhesives, furniture, furniture wax, even clothing—particularly if it’s been dry-cleaned. VOCs also are released by household products, like cleansers, detergents, disinfectants, spot removers, and air fresheners.
Not all VOCs are bad, but many are. Even in low concentrations, they can cause asthma and other respiratory problems, along with headaches, fatigue, eye irritation, skin rashes, and long-term damage to the liver, kidneys, and central nervous system. Some, like benzene, are known carcinogens. The Environmental Protection Agency estimates that 50 percent of all illnesses are caused or complicated by poor indoor air quality. Fortunately, you can dramatically lower the levels of many indoor air pollutants.
Advanced air purification technologies can reduce the amount of indoor air pollution. Researchers at the Simon Fraser University in British Columbia, Canada, studied 45 healthy people in a small town in Canada where wood-burning stoves—which generate fine particulate matter—were the main source of indoor air pollution. For one week, the participants used air purifiers with high efficiency particulate air (HEPA) air filters in their main activity room and in the bedroom. The units reduced the amount of indoor fine particulate matter by 60 percent.
The filters also reduced cardiovascular risk from indoor air pollution. Air pollution—indoor and outdoor—is a major risk factor for heart attack, stroke, heart failure, and death, according to a scientific statement from the American Heart Association. When the purifiers were on, the study participants had 9 percent better arterial function and 33 percent lower levels of C-reactive protein, a biomarker of inflammation. Other studies show that air purifiers with HEPA filters can reduce fine particulate matter in homes in a heavily trafficked area of a big city, and improve arterial health in the residents of the houses.
Advanced air cleaning technologies have been found to be even more effective than HEPA filters alone. In a 2022 study published in the International Journal of Environmental Research and Health, scientists found that ion-generating air purifiers outperformed conventional, filter-based air purifiers and reduced airway exposure to particulate matter by 20 percent more. Ions are atoms or molecules that have extra electrons in their structure, creating a negative electrical charge. They can neutralize airborne contaminants and kill germs and viruses.
One of the most advanced ionization systems is bipolar ionization. This system generates both positive and negative ions, which attach to airborne particles, causing them to clump together so they can be trapped by air filters or settle out of the air. Studies show bipolar ionization reduces coronavirus by 99 percent, particulates by 99 percent, microorganisms like bacteria and mold by 99 percent, and VOCs by 90 percent. This type of system is now used widely, including by airports, hospitals, universities, sports facilities, gaming facilities, and in residences.
Studies show that homes with carpeting have higher levels of indoor pollutants. To correct the problem, vacuum every three to four days. Swipe every area twice for optimal removal of pollutants. Look for a vacuum with a HEPA filter and opt for bags, which provide an extra layer of protection between your lungs and the vacuumed dust. The best type of bag is high filtration, which will trap more pollutants and allergens. Vacuums with bags are often the best performing, say consumer experts from the Good Housekeeping Research Institute.
Houseplants can remove VOCs from indoor air. The pollutants are absorbed through microscopic openings in leaves called stoma, transported to the roots, and biodegraded by microbes, which turn the chemicals into substances the microbes and plants can use. In a study from the University of Georgia, researchers tested 28 indoor plants for their ability to rid the air of five health-damaging VOCs, including benzene, toluene, and trichloroethylene.
The five plants with “superior removal abilities” were:
The seven plants with “intermediate removal efficiencies” were:
Bill Wolverton, PhD, an environmental scientist and author of How to Grow Fresh Air, has found that these additional plants effectively remove VOCs:
For maximum improvement of indoor air quality, multiple species are needed, say the University of Georgia researchers. Plants grown in hydroculture are 30 to 50 percent more effective in removing VOCs than those grown in potting soil. This is mostly due to greater airflow to the plant root zone, where microbes break down the VOCs.
