Many of us have been led to believe that houseplants can purify the air in our homes, offering a natural way to combat indoor pollution.
However, after reviewing the research, we've discovered that houseplants may not be as effective at improving indoor air quality as we once thought. Here's why.
The Myth Behind Air-Purifying Plants
The idea that houseplants can clean indoor air began with a 1989 NASA study, which explored whether plants could remove pollutants like volatile organic compounds (VOCs) in sealed environments, such as space stations. While the study showed that plants could absorb carbon dioxide and reduce VOCs like formaldehyde and benzene, further research has cast doubt on their real-world effectiveness.
What Recent Studies Reveal
A 2019 meta-analysis review of decades of research found that houseplants are not as effective at cleaning the air as initially believed. To see noticeable reductions in VOCs, you would need anywhere from 10 to 1,000 plants per square meter of space—far more than most of us would consider having in our homes. In fact, researchers concluded that natural ventilation, like air exchange with the outdoors, is much more responsible for air purification than houseplants.
Why Research Conditions Aren't Realistic
While earlier studies were conducted in small, sealed chambers with controlled variables, real-world conditions are quite different. Our indoor spaces are much larger and have various sources of pollutants present simultaneously. Additionally, fresh air is constantly circulating through our homes via natural ventilation, which further diminishes any potential contribution from plants to cleaner air.
Can Houseplants Actually Harm Air Quality?
In rare cases, houseplants can contribute to indoor air pollution. For example, overwatering can lead to mold growth, which, when disturbed, can trigger allergies and respiratory issues. Dust accumulating on plant leaves can also spread throughout the air, causing similar problems. And certain pests or plant pollen can aggravate allergies for some people. However, these issues typically occur when plants are not properly cared for.
What Really Helps Clean Indoor Air?
Instead of relying on houseplants, we can take more effective steps to improve indoor air quality. Here are a few strategies:
• Source Control: Eliminate VOCs by reducing the use of products like cleaning supplies, air fresheners, and paints, which contain these harmful compounds.
• Ventilation: Open windows and doors for 10-15 minutes each day to let in fresh outdoor air and reduce indoor air pollution.
• Air Cleaning: Use air purifiers with HEPA filters, which are proven to remove up to 99.97% of airborne particles. Changing furnace filters regularly also helps maintain air quality.
While houseplants may have some minor benefits, they're not a reliable solution for cleaning indoor air. Instead, we can focus on better ventilation, reducing pollution at the source, and using air purifiers to keep our indoor spaces healthy and breathable.
