Are Indoor Plants Good For Asthma? | Greenery & Lungs

There’s a natural curiosity about how elements within our homes influence our health, especially when dealing with conditions like asthma. Many of us appreciate the beauty and vibrancy plants bring to a living space, leading to questions about their deeper contributions to our well-being. Today, we’ll explore the science behind indoor plants and their relationship with asthma, offering a balanced perspective.

Understanding Asthma and Indoor Air Quality

Asthma is a chronic respiratory condition where airways narrow and swell, producing extra mucus. This makes breathing difficult and triggers coughing, wheezing, and shortness of breath. Managing asthma often involves controlling exposure to triggers, many of which are found indoors.

Indoor air quality significantly influences asthma symptoms. Our homes can harbor various substances that irritate sensitive airways, making it crucial to understand what’s floating around us.

Common Asthma Triggers Indoors

• Dust Mites: Microscopic creatures thriving in bedding, upholstery, and carpets, their droppings are a common allergen.
• Pet Dander: Tiny flakes of skin, saliva, or urine from animals can become airborne and trigger reactions.
• Mold Spores: Fungi that grow in damp areas, releasing spores that can be inhaled and cause respiratory irritation.
• Pollen: While primarily an outdoor allergen, pollen can enter homes through open windows or on clothing.
• Volatile Organic Compounds (VOCs): Gases emitted from certain solids or liquids, such as cleaning products, paints, new furniture, and building materials.
• Irritant Gases: From combustion sources like gas stoves or fireplaces, these can also affect breathing.

The National Institutes of Health reports that asthma affects over 25 million Americans, with symptoms often exacerbated by indoor allergens and irritants.

The Role of Air Quality

Good indoor air quality aims to minimize these triggers. This often involves proper ventilation, regular cleaning, and sometimes air purification systems. The idea that plants could contribute to this effort is appealing, especially for those seeking natural solutions.

Are Indoor Plants Good For Asthma: Examining the Evidence

The belief that indoor plants purify the air and thus help with asthma largely stems from research into their ability to remove specific airborne compounds. It’s a nuanced topic, with some promising findings and important considerations.

Air Purification Claims

Plants “breathe” through tiny pores on their leaves, called stomata, taking in carbon dioxide and releasing oxygen. During this process, they can also absorb other airborne compounds. Microbes in the soil around a plant’s roots also play a significant role, breaking down various substances.

Studies have shown that certain plants can indeed absorb VOCs like formaldehyde, benzene, and trichloroethylene from the air. These compounds are commonly found in household products and can contribute to poor indoor air quality. The mechanism involves both the plant’s leaves and the root-soil system working together to metabolize these substances.

Humidity Regulation

Plants release water vapor through a process called transpiration. In dry indoor spaces, a collection of plants can slightly increase ambient humidity. For some asthma sufferers, maintaining an optimal humidity level (typically between 30-50%) can be beneficial, as very dry air can irritate airways. Too much humidity, however, can promote mold growth, which is a significant asthma trigger.

The NASA Clean Air Study Revisited

Much of the public perception about plants as air purifiers originates from a 1989 study by NASA, which investigated ways to clean air in space stations. This research found that certain indoor plants could remove VOCs from sealed chambers.

The study identified plants like the Peace Lily, Chrysanthemum, and English Ivy as effective in reducing levels of benzene, formaldehyde, and trichloroethylene. This was a significant finding for confined spaces like spacecraft.

However, it is crucial to understand the context. The NASA study was conducted in small, sealed chambers, a far cry from a typical home with open windows, ventilation, and a much larger air volume. The concentration of VOCs used in the study was also often higher than what is typically found in residential settings. Replicating these effects in a standard living room would require an impractical number of plants, often hundreds, to make a noticeable difference in air quality for most homes.

Potential Benefits of Specific Plants for Air Quality

While the direct impact on asthma symptoms might be limited, some plants are recognized for their ability to process certain airborne compounds and contribute to a generally fresher indoor atmosphere.

• Spider Plant (Chlorophytum comosum): Known for its ability to filter formaldehyde and xylene. It’s also easy to care for and non-toxic.
• Peace Lily (Spathiphyllum): Helps remove benzene, formaldehyde, trichloroethylene, and ammonia. It also releases moisture into the air.
• Snake Plant (Sansevieria trifasciata): Filters formaldehyde, benzene, trichloroethylene, and xylene. It’s unique in that it converts a lot of CO2 to oxygen at night.
• Boston Fern (Nephrolepis exaltata ‘Bostoniensis’): A good humidifier and capable of removing formaldehyde.
• Areca Palm (Dypsis lutescens): An effective humidifier and can remove toxins like formaldehyde, xylene, and toluene.

Here’s a quick look at some commonly discussed plants and their reported air benefits:

Plant Name	Reported Benefit	Care Level
Spider Plant	Formaldehyde, Xylene	Easy
Peace Lily	Benzene, Formaldehyde, Trichloroethylene, Ammonia	Moderate
Snake Plant	Formaldehyde, Benzene, Trichloroethylene, Xylene	Very Easy
Boston Fern	Formaldehyde, Humidity	Moderate
Areca Palm	Formaldehyde, Xylene, Toluene, Humidity	Moderate

The Other Side: Potential Risks for Asthma Sufferers

While plants offer aesthetic appeal and some air benefits, it’s vital for individuals with asthma to be aware of potential downsides. Certain aspects of plant ownership can inadvertently trigger asthma symptoms.

Mold and Mildew Concerns

Overwatering is a common mistake that can lead to significant problems for asthma sufferers. Constantly damp soil creates an ideal breeding ground for mold and mildew. These fungi release spores into the air, which are potent asthma triggers for many individuals. Proper watering techniques are essential to prevent this. Using pots with drainage holes and emptying saucers regularly helps avoid standing water.

Pollen and Allergens

While most indoor plants produce minimal airborne pollen compared to outdoor varieties, some do produce pollen that can become an issue. Flowering plants, particularly those with visible pollen, can release allergens into the air. For individuals highly sensitive to pollen, even a small amount can cause respiratory distress. It’s prudent to choose non-flowering or low-pollen plants.

Dust Accumulation

Plant leaves, especially those with large or fuzzy surfaces, can accumulate dust. Dust is a well-known asthma trigger, containing dust mites, pet dander, and other irritants. Regular cleaning of plant leaves is necessary to prevent dust buildup. Wiping leaves gently with a damp cloth can keep them clean and also allow the plant to photosynthesize more effectively.

Selecting and Caring for Asthma-Friendly Plants

If you have asthma and wish to incorporate plants into your home, thoughtful selection and diligent care can help mitigate potential risks.

Low-Allergen Choices

Opt for plants that are known to produce little to no airborne pollen. Generally, plants with large, glossy leaves and no obvious flowers are better choices. Examples include:

• Snake Plant
• Spider Plant
• Peace Lily (remove flowers if pollen is an issue)
• Rubber Plant
• Dracaena varieties
• Pothos

Maintenance Practices to Mitigate Risks

1. Water Carefully: Allow the top inch or two of soil to dry out between waterings. Use pots with drainage holes and promptly discard any standing water in saucers.
2. Clean Leaves Regularly: Gently wipe leaves with a damp cloth weekly to remove dust and allergens. This also helps the plant “breathe” better.
3. Monitor for Mold: Inspect soil and pots for any signs of mold growth. If mold appears, scrape it off, allow the soil to dry out more thoroughly, and consider repotting with fresh, sterile soil.
4. Avoid Scented Plants: Some plants have strong fragrances that can irritate sensitive airways. Choose unscented varieties.
5. Use Sterile Potting Mix: When repotting, use a high-quality, sterile potting mix to reduce the introduction of mold spores or pests.
6. Consider Hydroponics: For those very sensitive to soil-borne mold, growing plants in water or a soilless medium (hydroponics) can be an option, eliminating soil as a mold source.

Here are some plant care tips specifically for those managing asthma:

Care Aspect	Asthma-Friendly Practice	Reasoning
Watering	Water only when topsoil is dry; ensure drainage.	Prevents mold growth in damp soil.
Dusting	Wipe leaves weekly with a damp cloth.	Removes accumulated dust and allergens.
Soil Choice	Use sterile, well-draining potting mix.	Reduces initial mold spores and prevents waterlogging.

Beyond Plants: Holistic Approaches to Indoor Air for Asthma

While indoor plants can be a part of a healthy home, they are not a standalone solution for asthma management. A comprehensive approach to indoor air quality involves several strategies.

Regular ventilation, such as opening windows for short periods, helps exchange stale indoor air with fresh outdoor air. Using high-efficiency particulate air (HEPA) filters in vacuum cleaners and air purifiers can capture airborne allergens and irritants. Consistent cleaning practices, including dusting and vacuuming, directly address common triggers like dust mites and pet dander. The Environmental Protection Agency provides guidelines on maintaining healthy indoor air quality, highlighting the significance of ventilation and source control for airborne pollutants.

Controlling humidity levels with dehumidifiers in damp areas can prevent mold growth. Addressing any water leaks or dampness in the home is also critical to preventing mold issues. For individuals with asthma, a multi-faceted strategy that combines thoughtful plant selection and care with other proven air quality measures offers the most beneficial path.