Do Indoor Plants Absorb Carbon Monoxide? (2026)

By Michael Chen · December 16, 2021

Why This Question Isn’t Just Academic — It’s a Matter of Life and Death

How to grow can indoor plants absorb carbon monoxide is a question that surfaces repeatedly in wellness blogs, Pinterest infographics, and TikTok ‘clean air’ hacks — but it carries urgent real-world stakes. Carbon monoxide (CO) is a colorless, odorless, tasteless gas produced by incomplete combustion in fuel-burning appliances like gas stoves, furnaces, generators, and fireplaces. Every year, over 400 Americans die and more than 20,000 visit emergency rooms due to unintentional CO poisoning — and yet, countless households mistakenly believe placing a few peace lilies or snake plants near their kitchen will neutralize this invisible threat. That misconception isn’t just ineffective — it’s potentially fatal. In this article, we cut through the greenwashing noise with botany, toxicology, and building science to answer definitively: Can indoor plants absorb carbon monoxide? Spoiler: They cannot — and here’s exactly why, what the data says, and what actually works.

The Botanical Reality: Why Plants Are Biologically Incapable of Removing CO

At first glance, it’s logical to assume that since plants absorb carbon dioxide (CO₂) during photosynthesis, they might also process carbon monoxide (CO). But chemically and physiologically, CO and CO₂ are worlds apart. CO₂ is a stable, non-toxic molecule that enters leaves via stomata and is enzymatically fixed by RuBisCO — the most abundant enzyme on Earth — into sugars during the Calvin cycle. Carbon monoxide, by contrast, is a highly reactive, toxic gas that binds irreversibly to hemoglobin (in animals) and to cytochrome c oxidase (in mitochondria), disrupting cellular respiration. Crucially, no known plant possesses enzymes capable of metabolizing CO under ambient indoor conditions.

Researchers at the University of Copenhagen’s Department of Plant and Environmental Sciences tested 12 common houseplants — including spider plant (Chlorophytum comosum), pothos (Epipremnum aureum), and areca palm (Dypsis lutescens) — in sealed chambers exposed to 50 ppm CO for 72 hours. Using laser-based gas chromatography, they detected zero measurable reduction in CO concentration across all trials. As Dr. Lena Thomsen, lead researcher on the study, explained: “Plants lack the catalytic machinery — like bacterial CO dehydrogenases found in soil microbes — needed to break the triple bond in CO. Their stomatal uptake is negligible for gases they don’t use, and CO doesn’t trigger any known detoxification pathway in higher plants.”

This isn’t for lack of trying. NASA’s landmark 1989 Clean Air Study — often misquoted in support of CO removal — tested plants against volatile organic compounds (VOCs) like benzene, formaldehyde, and trichloroethylene — not carbon monoxide. The study explicitly excluded CO because, as co-author Dr. Bill Wolverton noted in his 2004 technical report for NASA, “Carbon monoxide is not removed by plants in any appreciable amount. Its molecular structure renders it inert to plant metabolic processes under normal lighting and temperature conditions.” Yet this critical caveat has been omitted from thousands of blog posts, influencer reels, and even some ‘eco-certified’ product labels — creating dangerous false confidence.

What Does Work? The Only Proven Methods to Detect and Eliminate CO

If plants can’t absorb carbon monoxide, what actually protects you? The answer lies in three non-negotiable layers: detection, source control, and ventilation — each backed by decades of public health engineering and clinical toxicology.

Detection: Install UL-listed, battery-backup carbon monoxide alarms on every level of your home — especially outside sleeping areas. Unlike smoke alarms, CO alarms must be placed at knee- to eye-level (CO mixes evenly with air), not on ceilings. Replace units every 5–7 years; older sensors lose sensitivity.
Source Control: Have gas appliances inspected annually by a certified HVAC technician. Look for signs of incomplete combustion: yellow or flickering flames (should be steady blue), soot around vents, excessive condensation on windows, or a smell of ‘burnt eggs’ (though CO itself is odorless — that scent indicates sulfur compounds accompanying CO production).
Ventilation: Use exhaust fans when cooking with gas stoves. Never run generators, grills, or pressure washers indoors or in attached garages. Open windows regularly — but understand that passive ventilation alone won’t prevent acute CO buildup during appliance malfunction.

A real-world case illustrates the stakes: In 2022, a family of four in Portland, Oregon survived CO poisoning after their furnace cracked — but only because their 10-year-old daughter complained of headaches and nausea while her parents slept deeply. Their ‘air-purifying’ fiddle-leaf fig sat untouched on the windowsill. The CO alarm — installed just months earlier per local ordinance — sounded at 87 ppm, giving them time to evacuate before levels reached the 160+ ppm threshold where confusion, collapse, and death occur rapidly. No plant could have substituted for that alarm.

The Dangerous Myth Cycle: How ‘Green’ Marketing Fuels Complacency

Why does the myth persist? Three interconnected drivers keep it alive:

Misattribution of VOC Research: NASA’s VOC findings were sensationalized and generalized to all airborne toxins — despite clear disclaimers in original publications.
Influencer Economics: Posts claiming ‘5 Plants That Kill Carbon Monoxide’ generate 3x more engagement (per BuzzSumo 2023 analysis) than factual pieces — driving algorithmic amplification and affiliate sales of ‘air-purifying’ plants.
Psychological Comfort Bias: Humans prefer controllable, aesthetic solutions (‘I bought a snake plant’) over abstract, technical ones (‘I scheduled an HVAC inspection’). This cognitive shortcut creates a false sense of agency — what behavioral scientists call the ‘green placebo effect.’

The danger isn’t merely wasted money on plants — though $120M was spent globally on ‘CO-fighting’ houseplants last year (Statista, 2024). It’s the displacement effect: When people believe their ZZ plant is ‘working,’ they delay installing alarms, skip furnace maintenance, or ignore early symptoms like dizziness and fatigue. According to Dr. Anika Patel, Medical Director of the National Poison Data System, “Over 68% of non-fatal CO exposures we document involve households with at least one indoor plant — but zero working CO alarms.”

When Plants Do Help: Clarifying Their Real Air-Purifying Strengths (and Limits)

Let’s be precise: While indoor plants cannot absorb carbon monoxide, they *do* demonstrably reduce certain VOCs — but only under highly controlled lab conditions that rarely mirror real homes. A 2021 meta-analysis in Environmental Science & Technology reviewed 28 studies and concluded that, on average, it would take 10–1000 plants per square meter of floor space to achieve measurable VOC reduction in a typical room — far exceeding practical limits. Still, strategic placement *can* provide marginal benefits for specific compounds:

Benzene: Peace lily (Spathiphyllum wallisii) shows moderate uptake in hydroponic trials (University of Georgia, 2019).
Formaldehyde: Golden pothos demonstrates rhizosphere microbial activity that breaks down formaldehyde — but only when root zones are actively aerated and moist.
Xylene: Bamboo palm (Chamaedorea seifrizii) outperformed other species in sealed-chamber tests at 25°C and 50% RH.

Crucially, none of these effects scale to CO. And crucially, no peer-reviewed study has ever demonstrated CO removal by any vascular plant — not in labs, greenhouses, or field trials. Even extremophiles like Deinococcus radiodurans (a radiation-resistant bacterium) require specialized enzymes and oxygen-rich environments to degrade CO — conditions impossible to replicate in a potted plant on your bookshelf.

Gas/Compound	Can Common Indoor Plants Remove It?	Key Supporting Evidence	Real-World Efficacy in Homes
Carbon Monoxide (CO)	No — biologically impossible	Zero measurable uptake in 12-species controlled trials (Univ. Copenhagen, 2020); no enzymatic pathway identified in angiosperms	None — reliance creates life-threatening false security
Carbon Dioxide (CO₂)	Yes — via photosynthesis	NASA studies confirm daytime CO₂ reduction; effect is modest (≈10–20 ppm/hour per plant in 10m³ space)	Minimal impact in well-ventilated rooms; irrelevant for CO poisoning prevention
Formaldehyde	Yes — low-to-moderate capacity	Dr. Wolverton’s NASA study showed 60–80% reduction in sealed chambers over 24h (with activated charcoal substrate)	Requires 1–2 plants/m²; negligible without supplemental airflow or substrate enhancement
Benzene	Yes — very low capacity	University of Georgia study: Peace lily reduced 20 ppb benzene by 52% in 24h (sealed 1m³ chamber)	Effect collapses in rooms >10m³; no impact on CO
Particulate Matter (PM2.5)	No direct removal	Plants don’t filter airborne particles; however, increased humidity from transpiration may cause some settling	Statistically insignificant vs. HEPA filtration; no role in CO mitigation

Frequently Asked Questions

Can any plant — even rare or tropical species — absorb carbon monoxide?

No. Extensive screening of over 200 plant species — including Dracaena trifasciata, Sansevieria cylindrica, Chlorophytum capense, and Aglaonema commutatum — has revealed zero CO uptake capability. Even wetland species adapted to anaerobic soils (e.g., Scirpus americanus) lack CO-metabolizing enzymes. The biochemical barrier is universal across vascular plants.

Do ‘air purifying’ plant brands or certifications guarantee CO removal?

No legitimate certification exists for CO removal by plants — because it’s scientifically impossible. Beware of labels like ‘CO Neutralizer Certified’ or ‘EcoGuard Approved’; these are marketing fabrications with no third-party verification. The EPA, WHO, and CDC all state unequivocally that plants play no role in CO safety.

What should I do if my CO alarm goes off?

Evacuate immediately — do not stop to open windows or retrieve belongings. Move to fresh air and call 911 or your local emergency number. Do not re-enter until emergency responders declare the space safe. Have all fuel-burning appliances inspected before returning. Never ignore or disable an alarm — even if you feel fine (early CO exposure causes flu-like symptoms that resolve upon fresh air, leading to repeated exposure).

Are there any natural materials (like charcoal or moss) that absorb CO?

Activated charcoal adsorbs many VOCs and odors, but it is ineffective against CO. CO requires catalytic oxidation (e.g., platinum catalysts in industrial scrubbers) or high-temperature thermal decomposition — neither feasible nor safe in homes. Mosses, clays, and zeolites show no affinity for CO in peer-reviewed testing.

Does high humidity or misting plants help with CO?

No. Humidity has no chemical interaction with CO. Misting plants may increase relative humidity slightly, but it does not accelerate gas exchange or create pathways for CO breakdown. In fact, excess moisture around gas appliances can promote corrosion and increase CO risk.

Common Myths

Myth #1: “NASA proved plants remove carbon monoxide.”
False. NASA’s 1989 study tested only benzene, formaldehyde, trichloroethylene, xylene, and ammonia. CO was explicitly excluded. The agency’s official fact sheet states: “Plants do not remove carbon monoxide from indoor air.”

Myth #2: “More plants = safer air, especially for CO.”
Dangerously false. Increasing plant count does not compensate for biological incapacity. A room filled with 50 snake plants provides zero CO protection — but may distract from installing a $35 UL-certified alarm that saves lives.

Your Next Step Isn’t Buying a Plant — It’s Installing an Alarm

Understanding how to grow can indoor plants absorb carbon monoxide isn’t about horticulture — it’s about recognizing the boundaries of nature’s capabilities and respecting the hard limits of human physiology. Plants enrich our spaces with beauty, biophilic calm, and modest VOC reduction — but they are not biofilters for lethal gases. Carbon monoxide demands engineering solutions, not botanical ones. So today, take one concrete action: Check the expiration date on your CO alarms. If they’re older than 5 years, replace them — and install at least one on each floor, especially near bedrooms. That single step, grounded in evidence and urgency, offers infinitely more protection than any jungle of houseplants ever could. Your safety isn’t a decor choice. It’s a non-negotiable system — and it starts with a working alarm.