{"url":"https://whatshealthyandwhy.com/houseplants/houseplants-air-and-wellbeing","path":"/houseplants/houseplants-air-and-wellbeing","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/houseplants/houseplants-air-and-wellbeing.json","markdown":"https://whatshealthyandwhy.com/houseplants/houseplants-air-and-wellbeing.md"},"topic":{"slug":"houseplants","name":"Houseplants","url":"https://whatshealthyandwhy.com/houseplants"},"slug":"houseplants-air-and-wellbeing","order":1,"title":"Houseplants, Air Quality, and Wellbeing","question":"Do houseplants clean the air or improve how you feel?","answer":"Houseplants are unlikely to clean home air meaningfully, but small studies suggest they ease stress and lift mood a little.","description":"Houseplants do not clean home air in any meaningful way, but small trials link tending them to less stress. Plus mold, pet and child safety.","confidence":3,"confidenceNote":"The air-cleaning verdict rests on a quantitative review of 12 chamber studies; the mood benefit rests on small, short trials, so it is less certain.","evidenceSummary":{"rctCount":2,"observationalCount":3,"metaAnalysisCount":2,"totalParticipants":"4,700+","replicated":true,"newestStudyYear":2025},"category":{"categoryTitle":"What's Harming You","categorySlug":"harming-you","subcategoryName":"Your Home","subcategorySlug":"home","url":"https://whatshealthyandwhy.com/explore/harming-you/home"},"actions":["For cleaner air, open windows and use a HEPA purifier before buying plants; matching ordinary ventilation would take 10 to 1,000 plants per square meter of floor [1].","Keep plants you enjoy and will actually look after; in small trials, repotting a plant lowered stress markers and plants in hospital rooms went with less pain and anxiety [2][3].","Water only when topsoil is dry and check pots for mold: among 4,732 preschoolers, visible home mold was linked to asthma and wheeze, but potted plants were not [4]."],"cautions":["Cat owners: keep all true lilies and daylilies out of the home; as little as two leaves or part of one flower has been fatal to cats [5].","Parents and pet owners: check plants against a poison-control list before buying; most exposures in a poison-center review were mild accidental ingestions at home, but some needed hospital care [6].","People with severely weakened immune systems should ask their care team before keeping plants and potting mix nearby; infection control is a recognized barrier to plants in healthcare settings [7]."],"simpleText":"Houseplants are pleasant, but they do not clean your home's air in any meaningful way. A 2020 analysis of chamber experiments found you would need roughly 10 to 1,000 plants per square meter of floor to match what normal ventilation already does [1]. Small trials suggest that tending plants can lower stress and lift mood a little [2][3], so keep them for enjoyment, not purification.","mediumText":"How it works\n\nWhere the \"air-cleaning plants\" idea comes from\n\nExperiments in small sealed chambers show that potted plants can remove volatile organic compounds (VOCs), gases given off by paint, furniture and cleaning products, over many hours or days [1]. Plants take up some of the gas directly, and microbes in the soil and roots also break some down [8].\n\nWhy it does not work in a real home\n\nRooms are far larger than test chambers and constantly swap air with the outdoors. Researchers converted 196 results from 12 chamber studies into a clean air delivery rate, the same measure used for air purifiers. A single plant's median rate was about 0.023 cubic meters of air per hour, so matching normal air exchange would take 10 to 1,000 plants per square meter of floor space [1]. Studies in real homes and offices are few and mixed [8]. Air blown through a plant's root bed removed far more formaldehyde than a still pot, but that is an engineered filter, not a plant on a shelf [9]. See air purifiers and filters for what does work.\n\nMood and stress\n\nThe better-supported benefit is psychological. In a crossover study of 24 young men, repotting an indoor plant lowered sympathetic nervous system activity and diastolic blood pressure compared with a computer task, and they felt more comfortable and soothed [2]. In a randomized trial of 90 patients recovering from hemorrhoid surgery, those with plants in their rooms had lower blood pressure, pain, anxiety and fatigue [3]. Three office field experiments found that plant-filled offices improved perceived air quality, concentration and productivity [10]. One reason may be that people find rooms with plants more attractive [11]. The studies are small and short, so treat the effect as modest.\n\nMicrobes, mold and safety\n\nIn 155 homes, households with more than three plants had more diverse bacteria and fungi in their dust, but not more microbes overall [12]. Damp soil can grow mold, yet in a survey of 4,732 preschoolers potted plants were not linked to asthma, wheeze or allergic rhinitis, while visible mold was [4]. Some plants are dangerous to cats and children: lilies can kill cats [5], and most plant poisonings reported to one US poison center were accidental ingestions at home [6].\n\nFor the gases that actually matter indoors, see VOCs from paint and building materials.","deepText":"The evidence in detail\n\nAir cleaning: a quantitative review\n\nCummings and Waring reviewed 12 published chamber experiments and converted 196 results into clean air delivery rates (CADR) [1]. Single-plant rates spanned orders of magnitude, with a median of 0.023 cubic meters per hour, so potted plants would need to cover 10 to 1,000 per square meter of floor to match typical building ventilation of about one air change an hour [1]. The authors note that the chamber studies reported results in metrics that do not translate directly to real rooms, and they call for field research and other approaches such as biofiltration [1]. A separate review found that removal depends on species, light and gas concentration, that both leaf uptake and root-zone microbes contribute, and that studies in homes and offices are few with mixed results [8]. Laboratory work on golden pothos showed that forcing air through the root bed raised formaldehyde clean air delivery from about 5.1 to about 233 cubic meters per hour per square meter of bed, with microbes doing a large share of the work [9]. That points to active biofilters as a possible technology, not to a plant on a windowsill.\n\nWellbeing trials\n\nLee and colleagues ran a randomized crossover study in 24 young men, comparing repotting an indoor plant with a computer task [2]. After the plant task, participants felt more comfortable, soothed and natural, sympathetic activity fell by the end of the task while it rose during computer work, and diastolic blood pressure was lower [2]. Limitations: one short session, only young men, and a comparison task that is itself stressful.\n\nPark and Mattson randomized 90 patients recovering from hemorrhoid surgery to rooms with or without live plants [3]. Patients with plants had lower systolic blood pressure and lower ratings of pain, anxiety and fatigue, and they rated their rooms more highly [3]. Patients can see the plants, so blinding was impossible, and many outcomes were self-rated.\n\nDijkstra and colleagues showed 77 participants a photo of a hospital room containing either plants or a painting after a scenario about being hospitalized; those who saw plants reported less stress, explained by finding the room more attractive [11]. This was a photo experiment, not a hospital stay. Nieuwenhuis and colleagues ran three field experiments in large commercial offices in the Netherlands and the UK, two of them following workers for weeks to months, and found improved perceived air quality, concentration, workplace satisfaction and objective productivity in plant-enriched offices [10]. A 2025 systematic review of 124 studies of greenery in hospitals, eldercare and space habitats concluded that plants reduce stress, improve mood and may speed recovery, while noting barriers such as infection control [7]. Those settings are very different from a living room.\n\nMicrobes, mold and poisoning\n\nDockx and colleagues sequenced dust from 155 households in a birth cohort [12]. Households with more than three plants had 64 more bacterial taxa (95% CI 3-125) and 26 more fungal taxa (4-48) than households with none, with no clear difference in microbial load [12]. Whether that diversity helps or harms is unknown, and the design is cross-sectional.\n\nWeber and colleagues surveyed parents of 4,732 Bavarian preschoolers [4]. Visible mold, present in 4.7% of households, was linked to doctor-diagnosed asthma with recent symptoms (adjusted odds ratio 2.16, 95% CI 1.01-4.63), wheeze (1.60, 1.0-2.50) and allergic rhinitis symptoms (1.75, 1.07-2.87), whereas potted plants showed no association with respiratory health [4]. Parent-reported, cross-sectional data cannot settle cause.\n\nA review of 6,492 plant exposures at one regional US poison center found that 98% were unintentional, 92.4% occurred at home, 58.3% were ingestions, symptoms developed in 47.1% and 0.6% led to hospital admission [6]. The most common plants were cactus, oleander, lantana and bougainvillea, reflecting a southwestern setting, so the pattern may differ for typical indoor plants. For cats the picture is starker: true lilies and daylilies cause kidney damage, as little as two leaves or part of one flower has been fatal, all parts including pollen are toxic, and outcomes are excellent only if fluid treatment starts before kidney shutdown [5].\n\nConflicting and null evidence\n\nThe positive laboratory results on air cleaning come from sealed chambers or engineered systems [1][9], and studies in real buildings are few and mixed [8]. The wellbeing studies differ in design, are mostly short, and often rely on self-report. They measured short-term stress, mood and productivity, not long-term health.\n\nBottom line (confidence 3 of 5)\n\nThe evidence that ordinary potted plants do not clean home air is fairly strong. The evidence that plants and tending them ease stress and mood is modest and short-term. Choose plants for pleasure, ventilate for air, and check each plant's safety for pets and children.","deepTruncated":false,"references":[{"id":"1","title":"Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies","authors":"Cummings BE, Waring MS","year":2020,"journal":"J Expo Sci Environ Epidemiol","pmid":"31695112","url":"https://pubmed.ncbi.nlm.nih.gov/31695112/"},{"id":"2","title":"Interaction with indoor plants may reduce psychological and physiological stress by suppressing autonomic nervous system activity in young adults: a randomized crossover study","authors":"Lee MS, Lee J, Park BJ, et al.","year":2015,"journal":"J Physiol Anthropol","pmid":"25928639","url":"https://pubmed.ncbi.nlm.nih.gov/25928639/"},{"id":"3","title":"Ornamental indoor plants in hospital rooms enhanced health outcomes of patients recovering from surgery","authors":"Park SH, Mattson RH","year":2009,"journal":"J Altern Complement Med","pmid":"19715461","url":"https://pubmed.ncbi.nlm.nih.gov/19715461/"},{"id":"4","title":"Exploring the associations between parent-reported biological indoor environment and airway-related symptoms and allergic diseases in children","authors":"Weber A, Fuchs N, Kutzora S, et al.","year":2017,"journal":"Int J Hyg Environ Health","pmid":"28941773","url":"https://pubmed.ncbi.nlm.nih.gov/28941773/"},{"id":"5","title":"Lily toxicity in the cat","authors":"Fitzgerald KT","year":2010,"journal":"Top Companion Anim Med","pmid":"21147474","url":"https://pubmed.ncbi.nlm.nih.gov/21147474/"},{"id":"6","title":"Human Plant Exposures Reported to a Regional (Southwestern) Poison Control Center Over 8 Years","authors":"Enfield B, Brooks DE, Welch S, et al.","year":2018,"journal":"J Med Toxicol","pmid":"29330731","url":"https://pubmed.ncbi.nlm.nih.gov/29330731/"},{"id":"7","title":"Health effects of plants, light, and natural elements of biophilic interventions in confined settings: a systematic review","authors":"Zandi A, Wung SF","year":2025,"journal":"Front Physiol","pmid":"41438217","url":"https://pubmed.ncbi.nlm.nih.gov/41438217/"},{"id":"8","title":"Can ornamental potted plants remove volatile organic compounds from indoor air? A review","authors":"Dela Cruz M, Christensen JH, Thomsen JD, et al.","year":2014,"journal":"Environ Sci Pollut Res Int","pmid":"25056742","url":"https://pubmed.ncbi.nlm.nih.gov/25056742/"},{"id":"9","title":"Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification","authors":"Wang Z, Pei J, Zhang JS","year":2014,"journal":"J Hazard Mater","pmid":"25164387","url":"https://pubmed.ncbi.nlm.nih.gov/25164387/"},{"id":"10","title":"The relative benefits of green versus lean office space: three field experiments","authors":"Nieuwenhuis M, Knight C, Postmes T, et al.","year":2014,"journal":"J Exp Psychol Appl","pmid":"25068481","url":"https://pubmed.ncbi.nlm.nih.gov/25068481/"},{"id":"11","title":"Stress-reducing effects of indoor plants in the built healthcare environment: the mediating role of perceived attractiveness","authors":"Dijkstra K, Pieterse ME, Pruyn A","year":2008,"journal":"Prev Med","pmid":"18329704","url":"https://pubmed.ncbi.nlm.nih.gov/18329704/"},{"id":"12","title":"Indoor green can modify the indoor dust microbial communities","authors":"Dockx Y, Täubel M, Bijnens EM, et al.","year":2022,"journal":"Indoor Air","pmid":"35347789","url":"https://pubmed.ncbi.nlm.nih.gov/35347789/"}],"wordCount":1240,"source":{"path":"src/content/topics/houseplants/houseplants-air-and-wellbeing.md"},"citeAs":"“Do houseplants clean the air or improve how you feel?.” What's Healthy and Why. https://whatshealthyandwhy.com/houseplants/houseplants-air-and-wellbeing","notice":"General information backed by peer-reviewed research, not medical advice."}