The NASA Study: Where It All Began
The idea that indoor plants can purify air gained popularity after NASA's 1989 study. This research, conducted in sealed chambers, showed that certain plants could remove volatile organic compounds (VOCs) from the air
The study suggested that plants like golden pothos and spider plants were effective at removing formaldehyde, while chrysanthemums and gerbera daisies tackled benzene
However, it's crucial to understand the limitations of this study and how it translates to real-world environments.
• NASA study conducted in sealed chambers
• Certain plants showed the ability to remove specific VOCs
• Results may not directly apply to typical indoor spaces
Real-World Applications: Scaling Up the Research
Translating chamber studies to real-life settings presents significant challenges. A 1992 EPA review of the NASA study pointed out that to achieve similar pollutant removal rates in a typical house, one would need about 680 plants
This highlights the difficulty in scaling up laboratory findings to practical applications in homes and offices.
• 680 plants needed for effective air purification in a typical house
• Chamber studies don't accurately reflect real-world conditions
• Scaling up presents significant challenges
Recent Research: A More Comprehensive Look
A 2019 meta-analysis by Drexel University researchers examined decades of studies on plants and air quality. They found that to achieve meaningful air purification, you would need an impractical number of plants - between 10 to 1,000 per square meter of floor space
This study suggests that natural ventilation is far more effective at removing indoor VOCs than plants.
• The 2019 meta-analysis reviewed decades of research
• 10-1,000 plants per square meter needed for significant impact
• Natural ventilation outperforms plants in VOC removal
The Role of Ventilation
Multiple studies emphasize that ventilation plays a more significant role in indoor air quality than plants. Opening windows or using air handling systems is much more effective at removing pollutants
This doesn't negate the benefits of plants, but it puts their air-purifying abilities into perspective.
• Ventilation more effective than plants for air purification
• Opening windows or using air handling systems recommended
• Plants' air-purifying abilities may be overstated
Potential Benefits and Limitations
While plants may not be the air purifiers once thought, they still offer benefits. They can increase humidity and potentially decrease temperature in indoor spaces
However, it's important to note that plants may also release VOCs or harbor contaminants in their soil
• Some plants may release VOCs
• Soil may contain bacteria or other contaminants
The Verdict: Plants Are Great, But Not Air Purifiers
Current research suggests that while plants are beneficial for various reasons, their ability to significantly improve indoor air quality is limited. The 2019 Drexel University study concludes that the rate at which plants remove VOCs is orders of magnitude slower than standard air exchange rates in buildings
Therefore, while plants are wonderful additions to indoor spaces, they shouldn't be relied upon as air purifiers.
• Plants have limited impact on indoor air quality
• Standard air exchange rates are much more effective
• Plants offer other benefits but aren't efficient air purifiers
References:
Vanno, S. (2021). Houseplants for Healthier Indoor Air. Warren CCE Master Gardener.
Han, K. T., & Ruan, L. W. (2020). Effects of indoor plants on air quality: a systematic review. PubMed.
American Lung Association. (2023). Getting into the Weeds: Do Houseplants Improve Air Quality?
InterNACHI. (n.d.). Plants and Indoor Air Quality.
Drexel University. (2023). Study: Actually, Potted Plants Don't Improve Air Quality.
American Lung Association. (2024). Houseplants Don't Clean the Air.
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