Part 5-  Plants: the Guardians of Indoor Water and Air Quality

By Donnie Yance  

“The key to stopping the environmental apocalypse is not science but love.” – Steven Charleston

Previous posts in this series have covered how plants play a vital role in assisting the detoxification of dangerous chemicals out of our bodies through nutrition and supplementation. Plants also have little-known abilities to actually clean the water and air of our home environments.

Brewing Tea For Healthier Water?

A new study published in ACS Food Science & Technology by researchers at Northwestern University found that brewing tea can naturally remove heavy metals like lead and cadmium from drinking water. The study shows that heavy metal ions adhere to the surface of tea leaves through a process called adsorption, effectively trapping these contaminants. Once the tea bag or loose leaves are discarded, the harmful metals are removed along with them. 

“We’re not suggesting that everyone starts using tea leaves as a water filter,” said Northwestern’s Vinayak Dravid, the study’s senior author. “But our findings do demonstrate an unexpected health benefit to a beverage already consumed by billions of people worldwide.”

How Tea Leaves Act as Natural Filters

Tea, brewed from the processed leaves of the Camellia sinensis plant, has been extensively valued for its cultural and economic significance, yet its potential as a natural filter remains largely unexplored. Researchers discovered that the same structural and chemical properties that make tea ideal for brewing also enable it to act as an effective material for adsorption.¹

The porous structure of dried tea leaves provides a high surface area, allowing for maximum contact with water. Additionally, organic compounds in tea contain functional groups that can bind to metal ions, enhancing their ability to trap heavy metals during the brewing process. This unique combination makes tea an efficient, natural tool for filtering contaminants from water.

So the next time you brew a cup of hot black or green tea, you can feel even better about your choice of beverage. 

Concerns About Indoor Air Pollution

Indoor Air Quality (IAQ) has recently received increased attention from the international scientific community, political institutions, and environmental agencies for improving our comfort, health, and wellbeing. For many people, the health risks from exposure to indoor air pollution may be greater than those related to outdoor pollution.² 

Why? Because most people spend a majority of their lives in indoor environments, and this has a significant impact on human health as well as productivity.³ 

Indoor air pollution from tobacco smoking, heating, cooking, carpets, furniture, or poor indoor ventilation has been connected to a variety of conditions including: asthma, COPD, infections, allergies, cancer, poor memory, weak concentration, impaired cognitive function, birth defects, heart disease, fatigue, and headaches. 

Air pollution is also related to several eye diseases, including conjunctivitis, glaucoma, cataracts, and age-related macular degeneration.⁴ 

Exposure to Indoor Air Pollution Linked to Breast Cancer

Indoor air pollution is created by the release of harmful pollutants inside. These can include fine particulate matter, carbon monoxide, formaldehyde, and various other toxins.

Long-term exposure to air pollution at home and at work is associated with an increased risk of breast cancer, according to research presented at the ESMO Congress 2023. Researchers found that an increase in exposure to fine particulate matter measuring 2.5 microns or less (PM_2.5) was associated with a significant increase in the risk of breast cancer.⁵

The average American is exposed to 5,000 times the safe level of bisphenol A (BPA). Reduced expression of tumor suppressor genes (TSGs) increases the susceptibility to breast and other cancers. However, only a small percentage of breast tumors is related to family history and mutational inactivation of TSGs. 

Epigenetics refers to non-mutational events that alter gene expression. Endocrine disruptors found in foods and drinking water may disrupt epigenetic hormonal regulation and increase the risk of several cancers including breast and prostate. Researchers have found that environmental pollutants like tobacco smoke, industrial chemicals, arsenic, and BPA can contribute to changes in gene expression that correlate with breast cancer.⁶

The leaching of BPA into food and drink containers has been attributed to its widespread detection in human urine and plasma. Estimates suggested that ~90% of total human exposure to BPA originates from foods.⁷

⁸

Indoor air pollution is particularly pernicious because people are often steeped in it for long periods of time on a daily basis.

⁹

The Ability of Plants to Adapt to Stressors

Plants are living organisms that have a form of consciousness just as we do. They are able to “sense” and “respond,” and have evolved distinct strategies to modulate biological processes. Plants can synthesize various protective molecules in response to environmental stresses like sun, drought, floods, and pests.¹⁰

Nature and plants never cease to amaze me. It turns out that plants can efficiently remove toxic cancer-causing fumes, including compounds such as benzene and gasoline, from indoor air.

When exposed to a small amount of a stressor, like the toxic substance dioxin, plants can boost their response to other stressors as well. This form of hormetic adaptation is referred to as “xenohormesis.”

“Xeno” comes from the Greek word for “foreign” and “hormesis” is translated as “that which excites”.  Thus, xenohormesis is the concept that the chemical stress response of one organism can benefit another (foreign) organism. Xenohormesis most commonly refers to the ability of a stressed plant to pay forward the benefits of resilience and survival to the animals that consume them. For example, plants create chemicals called heat shock proteins and sirtuins, such as the well-known resveratrol, that have been linked to longevity.¹¹

I am always sharing with people that wild edible food and medicinal herbs are much healthier than cultivated food and farmed medicinal herbs.  Plants found in nature are usually forced to endure some extreme stressors, including weather (sun, wind, spring freezes, droughts, floods, and storms), predators, pests, and pollution.  Science is telling us that it’s the hardships that a plant goes through that stimulate the most powerful hormetic effects. This creates an adaptive response which makes the plant stronger and more resilient to future insults.

Plants to the Rescue for Our Toxic Indoor Air

A recent study was led by Associate Professor Fraser Torpy in Australia. Researchers found that the Ambius Small Green Wall, a wall-mounted planter containing a mix of houseplants, was, “highly effective at removing harmful, cancer-causing pollutants, with 97% of the most toxic compounds removed from the surrounding air in just eight hours.”

Poor indoor air quality is responsible for 6.7 million premature deaths globally, according to the World Health Organization. Most people spend 90% of their time indoors at home, school, or work, so adopting new strategies to improve indoor air quality is critical.

Previous studies on indoor plants have shown they can remove a broad range of indoor air contaminants, however this is the first study into the ability of plants to clean up gasoline vapors, which are one of the largest sources of toxic compounds in buildings worldwide.

Associate Professor Torpy explained, “Not only can plants remove the majority of pollutants from the air in a matter of hours, they remove the most harmful gasoline-related pollutants from the air most efficiently. Even more impressive, was the fact that the more concentrated the toxins in the air, the faster and more effective the plants became at removing the toxins, showing that plants adapt to the conditions they’re growing in.” ¹²

Indoor Nitrogen Dioxide

Indoor concentrations of Nitrogen dioxide (NO₂) are a function of both indoor and outdoor sources, where elevated outdoor concentrations (e.g. in cities with a greater density of traffic) will inevitably produce higher indoor concentrations. High NO₂ within indoor air is associated with many health problems.¹³  Reducing the indoor NO₂ concentrations in buildings would likely reduce health issues and save millions of dollars in health-care costs.¹⁴ 

The Healing Power of Indoor Plants

My home is filled with houseplants that serve multiple wonderful purposes. Beyond their natural beauty, they create a vital connection to the outdoor world and nature. These green companions work miraculously to detoxify our indoor air while providing a sense of spiritual nourishment. Each plant acts as a natural air purifier, transforming our living space into a healthier, more vibrant environment.

Studies show that indoor plants reduce stress levels and anxiety, improve concentration, and boost creativity. For example, a systematic review of 42 studies showed that indoor plants affect participants’ objective functions positively, particularly in terms of relaxed physiology and improved cognition.¹⁵ The simple act of tending to plants can lower blood pressure and create moments of mindfulness in our busy lives, having a stress-reducing effect.¹⁶ In our technology-driven world, these green companions provide a necessary return to something real and living, helping to ground us in the present moment.

The Wellbeing Connection 

The relationship between plants and human well-being runs deep. Indoor plants improve our quality of life by:

• Reducing mental fatigue
• Increasing productivity and focus
• Enhancing mood and emotional stability
• Creating a sense of accomplishment through care and nurturing
• Providing natural humidity that benefits our respiratory health
• Adding life and energy to otherwise static spaces

Maintaining an indoor garden becomes a form of moving meditation, offering spiritual benefits that extend far beyond the physical care of plants. Each plant becomes a teacher of patience, impermanence, and growth. Through them, we learn to observe subtle changes, appreciate slow progress, and understand the rhythms of life. The practice of plant care connects us to ancient wisdom about the interconnectedness of all living things and our role as stewards of nature.

What Are Some of the Best Plants For Cleaning Indoor Air?

Zamioculcas Zamiifolia (ZZ Plant)

The ZZ plant (Zamioculcas zamiifolia) stands out as a remarkable addition to any indoor space, combining aesthetic appeal with practical benefits. Its glossy, waxy green foliage not only creates a striking visual display but also serves a crucial function in improving indoor air quality.

Air-Purifying Capabilities Recent scientific research has highlighted the ZZ plant’s role in creating healthier indoor environments. A groundbreaking study published in Air Quality, Atmosphere and Health (February 2022)¹⁷ identified the ZZ plant as one of the three most effective houseplants for reducing nitrogen dioxide levels in indoor air. This finding is particularly significant because exposure to nitrogen dioxide has been linked to serious respiratory illnesses, decreased lung function, and airway inflammation.

Beyond nitrogen dioxide, the ZZ plant demonstrates impressive versatility in filtering other harmful compounds from the air, including:

• Benzene
• Toluene
• Xylene

Practical Benefits While some air-purifying plants may show stronger filtering capabilities, the ZZ plant offers unique advantages:

• Thrives in low-light conditions
• Requires minimal maintenance
• Adapts to various growing environments
• Maintains consistent air-cleaning performance even in suboptimal conditions

This combination of durability and air-purifying abilities makes the ZZ plant an ideal choice for busy individuals or spaces with challenging growing conditions. Whether placed in a dim corner of an office or a bright living room, this resilient plant continues its vital work of contributing to cleaner indoor air.

The Heartleaf Philodendron (Philodendron hederaceum)

With its charming heart-shaped leaves that inspired its name from the Greek word for “love,” the Philodendron combines beauty with powerful air-purifying abilities. This beloved houseplant has earned its popularity through both its attractive appearance and its remarkable health benefits.

Air-Purifying Benefits- NASA research has confirmed the Heartleaf Philodendron’s impressive ability to cleanse indoor air.¹⁸ The plant effectively removes several harmful compounds including:

• Formaldehyde
• Benzene
• Trichloroethylene

These toxins, commonly found in household products and building materials, are harmful to human health. Through natural processes of photosynthesis and transpiration, the plant:

• Absorbs airborne toxins
• Increases oxygen levels
• Helps maintain healthy humidity levels
• Creates a fresher indoor environment

The Heartleaf Philodendron stands out as an ideal choice for beginning plant owners due to its forgiving nature:

• Tolerates low-light conditions
• Survives occasional neglect in watering
• Adapts well to various indoor environments
• Requires minimal maintenance

This combination of air-purifying power and easy care makes the Philodendron an excellent choice for anyone looking to improve their indoor air quality while adding natural beauty to their space.

Peace Lily (Spathiphyllum)

The Peace Lily is widely regarded as one of the most effective houseplants for purifying indoor air. It excels at removing a variety of airborne toxins, including benzene, formaldehyde, trichloroethylene, ammonia, and carbon monoxide, which are found in household cleaners, paints, and furniture. Peace Lilies are also known for increasing humidity by releasing moisture, which can help alleviate dry air conditions and improve respiratory health. With its elegant white blooms and low maintenance requirements, the Peace Lily not only enhances the beauty of a space, but also creates a healthier, more refreshing indoor environment.

 Spider Plant (Chlorophytum comosum)

The Spider Plant is a standout choice for improving indoor air quality. This resilient plant is particularly effective at removing common air pollutants such as carbon monoxide, formaldehyde, and xylene. Its dense foliage allows for a higher surface area to absorb toxins and release oxygen, creating a fresher indoor environment. Additionally, the Spider Plant is known for its ability to thrive in a variety of conditions, including low light, and is highly tolerant of neglect, making it a perfect option for busy households or office spaces. Its air-purifying properties and ease of care make it a popular and practical addition to any

Snake Plant (Sansevieria trifasciata)

The Snake Plant (Sansevieria trifasciata), also known as Mother-in-Law’s Tongue, stands out as one of the most effective natural air purifiers among houseplants. Its striking architectural leaves not only add modern elegance to any space but also work continuously to create a healthier indoor environment.

This combination of powerful air purification and minimal care requirements makes the Snake Plant an ideal choice for improving indoor air quality in homes and offices. Its ability to work day and night, coupled with its striking appearance, truly earns its reputation as a powerhouse among air-purifying plants.

This remarkable plant excels at removing multiple airborne toxins:

• Formaldehyde (found in furniture and building materials)
• Benzene (present in paints and cleaning products)
• Xylene (common in adhesives and floor finishes)
• Trichloroethylene (found in printing inks and paints)

Unique Nighttime Oxygen Production- Unlike most houseplants, the Snake Plant possesses a special adaptation called Crassulacean Acid Metabolism, which allows it to:

• Convert carbon dioxide into oxygen during the night
• Continue air purification around the clock
• Make it particularly beneficial in bedrooms
• Potentially contribute to better sleep quality

Low-Maintenance Champion- The Snake Plant’s resilient nature makes it perfect for both beginners and busy plant owners:

• Tolerates low light conditions
• Survives extended periods without water
• Adapts to various temperature ranges
• Resists most pests and diseases
• Thrives in nearly any indoor environment.

Areca Palm (Dypsis lutescens): Nature’s Humidifier and Air Purifier

The Areca Palm (Dypsis lutescens) stands as one of the most elegant and effective natural air purifiers available. With its graceful, feathery fronds and bright green foliage, this tropical beauty serves as both a stunning decorative element and a powerful tool for improving indoor air quality.

This combination of air purification, natural humidification, and tropical beauty makes the Areca Palm an excellent choice for those looking to enhance their indoor environment while adding a touch of natural elegance.

This versatile palm effectively removes several harmful indoor pollutants:

• Benzene (found in plastics and synthetic fibers)
• Formaldehyde (present in furniture and building materials)
• Xylene (common in paints and varnishes)
• Other volatile organic compounds (VOCs)

The Areca Palm excels as a natural humidifier, offering significant benefits:

• Releases substantial moisture into the air
• Helps maintain optimal indoor humidity levels
• Reduces dry skin and respiratory issues
• Prevents static electricity buildup
• Creates a more comfortable living environment

While not as low-maintenance as some air-purifying plants, the Areca Palm thrives with:

• Bright, indirect light
• Regular watering when soil surface feels dry
• Moderate humidity levels
• Well-draining soil
• Temperatures between 65-75°F (18-24°C)

Perfect Placement For maximum benefit, consider placing Areca Palms in:

• Living rooms with filtered sunlight
• Office spaces near windows
• Bedrooms away from direct sun
• Any room that tends to become dry.

Aloe Vera

Aloe vera proves itself as more than just a medicinal plant. This versatile succulent serves as both a natural first-aid station and an efficient air purifier, making it an invaluable addition to any home.

I have several Aloe vera plants in my home. Aloe vera absorbs these toxins while releasing oxygen, helping to improve air quality in enclosed spaces. Its ability to thrive in bright, indirect light and its minimal watering needs make it an excellent choice for low-maintenance greenery.

This combination of air-purifying abilities, healing properties, and easy care makes Aloe vera an essential plant for health-conscious households. Its compact size allows for multiple plants throughout the home, maximizing both its air-cleaning and therapeutic benefits.

NASA research¹⁹ has demonstrated Aloe vera’s impressive air-cleaning abilities:

• Effectively removes formaldehyde from indoor air
• Filters out benzene from household products
• Shows rapid results, with significant toxin removal in just 24 hours
• Continues to purify air around the clock

Common Sources of Toxins It Removes:

• Household cleaning products
• Paint and varnishes
• Furniture polish
• Synthetic materials
• Personal care products

Healing Benefits Beyond air purification, Aloe vera offers multiple therapeutic uses:

• Soothes minor burns and sunburns
• Helps heal minor cuts and scrapes
• Reduces skin inflammation
• Provides natural moisturizing properties
• Contains beneficial compounds for skin health

As a succulent, Aloe vera thrives with minimal attention:

• Requires infrequent watering
• Tolerates various light conditions
• Adapts to indoor environments
• Propagates easily
• Survives in most home temperatures.

House Plants, Air Filters, and Essential Oils

My home is surrounded with both plants and trees of which I planted every single one. Indoor house plants inhabit almost every room of my home. They are part of our family, and besides their beauty, they bless us with healing powers by keeping the air we breathe healthy. We also have two good HEPA filters to be sure our home air environment is healthy. 

Lastly, we frequently have an essential oil diffuser going as well. Adding essential oils (EOs) into the air can rid the air of small particles of various pathogens such as viruses, mold, and bacteria.  One blend we use which I created for the Mederi Center Clinic is a combination of: tea tree, eucalyptus, clove, thyme, sweet orange, lavender, rosemary, lemon grass, cinnamon, myrrh, oregano, nutmeg, and bergamot.

Aromatherapy and COIV-19 Recovery

A study assessed aromatherapy in patients with fatigue after COVID-19 infection. In a double-blinded-randomized-control trial by Hawkins et al., 44 female participants who suffered from fatigue for more than 5 months after COVID-19 infection were randomized to inhale essential oils (clove bud, orange peel, frankincense, and thyme) or placebo (inert, odorless fractionated coconut oil) for 2 weeks. Results demonstrated that aromatherapy significantly improved energy levels among women recovering from COVID-19.²⁰ 

“The first effect of not believing in God is that you lose your common sense.”   

 – G. K. Chesterton

Conclusion 

Many plants have a miraculous ability to detoxify water and air. Tea leaves have been shown to remove heavy metal atoms from drinking water, and studies have highlighted the remarkable air-purifying capabilities of various common houseplants. They have been shown to effectively absorb pollutants like formaldehyde, benzene, and other volatile compounds even in a controlled, sealed environment. These studies’ findings underscore the potential of these plants as natural allies in improving indoor air quality. Houseplants such as Peace Lilies, Snake Plants, Spider Plants, and Aloe Vera demonstrated their power to clean the air within just 24 hours, showcasing an impressive impact in a short period. 

While their effect may be less dramatic in larger or more open spaces, incorporating these plants into indoor environments at home, school, or work, can be a valuable addition for reducing harmful airborne toxins and promoting a healthier living space.

This green sanctuary we create in our homes becomes more than just decoration; it becomes a living, breathing space that nurtures both body and soul. As we care for our plants, they care for us in return, creating a beautiful cycle of giving and receiving that enriches our daily lives with purpose and peace.

About the Author:

Donald R. Yance is the founder of the Mederi Center. A Clinical Master Herbalist and Certified Nutritionist, Donnie is renowned for his extraordinary knowledge and deep understanding of the healing properties of plants and nutrition, as well as of epigenetics, laboratory medicine, oncologic pathology, and molecular oncology. He is a professional member of the American Herbalists Guild, National Association of Nutrition Professionals, Academy of Integrative Health and Medicine, and the Society for Integrative Oncology.

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2.  Cincinelli A, Martellini T. Indoor Air Quality and Health. Int J Environ Res Public Health. 2017 Oct 25;14(11):1286. doi: 10.3390/ijerph14111286.

3.  Mannan M, Al-Ghamdi SG. Indoor Air Quality in Buildings: A Comprehensive Review on the Factors Influencing Air Pollution in Residential and Commercial Structure. Int J Environ Res Public Health. 2021 Mar 22;18(6):3276. doi: 10.3390/ijerph18063276.

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5.  Fervers B, Duboeuf M, Amadou A, et al. Long-term residential and workplace exposure to air pollution and breast cancer risk: A case-control study nested in the French E3N cohort from 1990 to 2011. Presented at ESMO Congress 2023. Oct. 20-24, 2023. Madrid, Spain. Abstract 238MO.

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11.  Douillard, John DC, CAP, Xenohormesis: Why Imperfect Food May be Your Healthiest Option, May 13, 2021, https://lifespa.com/health-topics/xenohormesis-stressed-plant-benefits/

12.  University of Technology Sydney. “Plants remove cancer causing toxins from air: Plants can efficiently remove toxic gasoline fumes from indoor air..” ScienceDaily. ScienceDaily, 26 May 2023. <www.sciencedaily.com/releases/2023/05/230526121110.htm>. https://www.ambiusindoorplants.com.au/ambius-capability/ambius-and-uts-research-study

13.  World Health Organisation (2010) WHO guidelines for indoor air quality: selected pollutants. ISBN: 9789289002134. Available at: https://www.who.int/publications/i/item/9789289002134

14.  Guerriero C, Chatzidiakou L, Cairns J, Mumovic D (2016) The economic benefits of reducing the levels of nitrogen dioxide (NO₂) near primary schools: the case of London. J Environ Manage 181:615–622

15.  Han KT, Ruan LW, Liao LS. Effects of Indoor Plants on Human Functions: A Systematic Review with Meta-Analyses. Int J Environ Res Public Health. 2022 Jun 17;19(12):7454. doi: 10.3390/ijerph19127454. PMID: 35742700; PMCID: PMC9224521.

16.  Lee MS, Lee J, Park BJ, Miyazaki Y. Interaction with indoor plants may reduce psychological and physiological stress by suppressing autonomic nervous system activity in young adults: a randomized crossover study. J Physiol Anthropol. 2015 Apr 28;34(1):21. doi: 10.1186/s40101-015-0060-8. PMID: 25928639; PMCID: PMC4419447.

17.  Gubb, C., Blanusa, T., Griffiths, A. et al. Potted plants can remove the pollutant nitrogen dioxide indoors. Air Qual Atmos Health 15, 479–490 (2022). https://doi.org/10.1007/s11869-022-01171-6

18.  Bryan E. Cummings, BE., Waring MS., Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies, Journal of Exposure Science & Environmental Epidemiology (2020) 30:253– 261, https://doi.org/10.1038/s41370-019-0175-9

19.  Gubb, C., Blanusa, T., Griffiths, A. et al. Potted plants can remove the pollutant nitrogen dioxide indoors. Air Qual Atmos Health 15, 479–490 (2022). https://doi.org/10.1007/s11869-022-01171-620.  Hawkins J, Hires C, Keenan L, et al. Aromatherapy blend of thyme, orange, clove bud, and frankincense boosts energy levels in post-COVID-19 female patients: a randomized, double-blinded, placebo controlled clinical trial. Complement Ther Med 2022; 67: 102823.

20.  Hawkins J, Hires C, Keenan L, et al. Aromatherapy blend of thyme, orange, clove bud, and frankincense boosts energy levels in post-COVID-19 female patients: a randomized, double-blinded, placebo controlled clinical trial. Complement Ther Med 2022; 67: 102823.