Do Indoor Plants Improve Air Quality? Science-Backed Facts

By Jennifer Lee · February 22, 2026

Yes, indoor plants can improve air quality by absorbing pollutants like benzene, formaldehyde, and trichloroethylene through their leaves and roots, and by increasing humidity and oxygen levels. However, their impact is modest compared to mechanical air purifiers or proper ventilation.

How Indoor Plants Affect Air Quality

Indoor plants contribute to cleaner air primarily through natural biological processes. During photosynthesis, they absorb carbon dioxide and release oxygen. More importantly, they help remove volatile organic compounds (VOCs) commonly found in homes and offices.

Natural Air Purification Mechanisms

Phytoremediation: Plants absorb airborne toxins through stomata in their leaves.
Microbial activity: Soil microbes around plant roots break down pollutants.
Transpiration: Releases moisture into the air, improving humidity and reducing dust.
Particulate capture: Leaves trap some airborne particles like dust and mold spores.

Scientific Evidence Behind Plant-Based Air Cleaning

The idea that houseplants clean indoor air largely stems from a 1989 NASA Clean Air Study. While conducted in sealed chambers, the results sparked widespread interest in using plants for indoor air improvement.

Plant Species	Formaldehyde Removal Rate (μg/m³/h)	Benzene Removal Rate (μg/m³/h)	Test Environment
Chrysanthemum morifolium	6.7	5.4	Sealed chamber (0.3 m³), 24 hrs
Sansevieria trifasciata	5.2	3.8	Sealed chamber (0.3 m³), 24 hrs
Epipremnum aureum	4.8	4.1	Sealed chamber (0.3 m³), 24 hrs
Spider Plant (Chlorophytum comosum)	4.5	3.6	Sealed chamber (0.3 m³), 24 hrs
Ficus benjamina	3.9	3.2	Sealed chamber (0.3 m³), 24 hrs

Table data source:1, 2

The data shows chrysanthemums and snake plants are among the most effective at removing formaldehyde and benzene. However, these rates were measured in small, sealed environments—real-world effectiveness in typical rooms is significantly lower due to air exchange and larger volumes.

Limitations of Indoor Plants in Air Purification

While promising in controlled studies, real-world performance of houseplants in improving air quality has notable limitations:

A single plant may only clean a few cubic feet of air per hour.
You would need 10–100 plants per square meter to match the air-cleaning capacity of a HEPA filter.
Plants do not remove fine particulates (PM2.5) or carbon monoxide effectively.
Overwatered plants can promote mold growth, worsening air quality.

Best Indoor Plants for Air Quality

Certain species consistently perform well in air purification tests and are easy to maintain:

Top 5 Air-Purifying Houseplants

Snake Plant (Sansevieria trifasciata): Removes formaldehyde, benzene, xylene; thrives in low light.
Peace Lily (Spathiphyllum spp.): Effective against ammonia, formaldehyde; increases humidity.
Pothos (Epipremnum aureum): Hardy vine that removes multiple VOCs; ideal for beginners.
Spider Plant (Chlorophytum comosum): Safe for pets, removes xylene and formaldehyde.
Areca Palm (Dypsis lutescens): Excellent humidifier and VOC absorber; needs bright, indirect light.

Maximizing Air Quality Benefits from Indoor Plants

To get the most out of your houseplants:

Group several plants together to increase collective impact.
Use activated charcoal in soil to boost filtration.
Maintain healthy plants—dusty or stressed plants are less effective.
Ensure proper drainage to prevent mold and mildew.
Combine with ventilation and air purifiers for best results.

Frequently Asked Questions About Indoor Plants and Air Quality

Do houseplants really clean the air?

Yes, but on a limited scale. Studies show houseplants can remove certain volatile organic compounds (VOCs) like formaldehyde and benzene, especially in sealed environments. However, their effect in typical homes is minor compared to HVAC systems or air purifiers.

How many plants do I need to improve air quality in a room?

Research suggests you’d need 10 to 100 plants per square meter to achieve measurable air purification—far more than most people can accommodate. For practical benefits, aim for 1–2 large, high-performing plants per medium-sized room.

Which indoor plant is best for removing toxins?

The chrysanthemum (Chrysanthemum morifolium) ranks highest in formaldehyde and benzene removal according to NASA’s study. Snake plants and peace lilies are also top performers and easier to care for in home settings.

Can plants reduce carbon dioxide levels indoors?

Yes, during daylight hours, plants absorb CO₂ and release oxygen via photosynthesis. However, the amount is negligible in a typical room. You’d need dozens of large plants to make a noticeable difference in CO₂ concentration.

Are there any risks to using indoor plants for air quality?

Yes. Overwatering can lead to mold in soil, which releases spores into the air. Some plants may trigger allergies. Ensure proper care, use well-draining pots, and avoid overcrowding to prevent unintended air quality issues.