Plants: Natural Air Purifiers?

Plants can absorb pollutants, and they are increasingly being used to combat air pollution. This is known as phytoremediation.

Some plants are particularly effective at filtering pollutants from the air. For example, conifers are good natural purifiers, as their dense canopy of needle-like leaves is very effective at trapping pollutants.

In addition to filtering air pollution, plants can also help reduce pollution by providing shade, which reduces the need for air conditioning and the emissions that come with it.

Some plants are better at absorbing certain types of pollution than others. For example, aloe vera, spider plants, snake plants, bamboo, and warneck dracaena are all good at filtering formaldehyde.

The best trees to reduce air pollution

Trees are a crucial part of reducing air pollution, and certain species are better at it than others. Here are some of the best trees for the job:

Yew (Taxus baccata)

The yew is an excellent choice for reducing air pollution. A study from the University of Surrey found that yew trees removed the most air pollution out of ten different tree species tested. The slightly broader and roughened needles of the European yew are particularly effective at capturing urban pollution. However, it is important to note that yew trees are poisonous and should not be planted near school playgrounds or other areas where children may be present.

Silver Birch, Elder, and Conifers

Silver birch, yew, and elder trees are also effective air pollution fighters. A study by Barbara Maher and colleagues at the University of Lancaster found that these trees had the highest reduction rates of particulate matter (PM), with hairs on their leaves contributing to reduction rates of 79%, 71%, and 70%, respectively. Conifers, such as pines and cypresses, are also good natural air purifiers due to their large surface area and needle arrangement.

Cotoneaster Franchetii

The bushy, hairy-leafed cotoneaster franchetii is a "super plant" when it comes to soaking up pollution on busy roads. A study by the Royal Horticultural Society found that this species was at least 20% more effective at reducing pollution on major city roads with heavy traffic compared to other shrubs. However, it did not make a significant difference on quieter streets.

Japanese Cedar (Camellia Japonica) and Lawson's Cypress (Chamaecyparis Lawsoniana)

These two tree species are notable for their awl-shaped leaves, which have been found to be highly effective at stripping pollution from the air.

In general, evergreen trees with smaller leaves tend to be better at improving air quality. Trees with rough and hairy leaves are also advantageous, as they can capture more pollution. Additionally, trees with woody frameworks are effective at capturing carbon.

Plants that absorb indoor air pollution

Plants can absorb pollutants, and certain plants are better at absorbing certain types of pollutants.

According to a NASA study, flowering plants such as chrysanthemums and gerbera daisies are effective at removing benzene from the atmosphere. Golden pothos, spider plants, and philodendron are the most effective in removing formaldehyde molecules. Other top performers were red-edged dracaena and the peace lily.

The government of India also published a study that analysed the effects of certain species of plants on indoor air quality. The study found that areca palm, pothos (known as Mother-in-Law's Tongue), and the Money Plant were the most effective at improving indoor air quality.

Other plants that are good at absorbing indoor air pollution include:

• Rubber trees
• Chinese evergreens
• Snake plants
• Devil's Ivy
• Weeping Fig
• Bamboo palms
• Parlor Palm
• Boston ferns
• Kimberly queen ferns
• Aloe vera
• Philodendron Heartleaf
• Flamingo Lily or Pink Anthurium
• Dracaena Warneckii (White Jewel)
• English ivy
• Lady Palm (Rhapis Excelsa)
• Janet Craig (Dracaena Deremensis)
• Barberton Daisy (Gerbera Daisy)
• Chrysanthemums

Phylloremediation of air pollutants

Plants can absorb gaseous pollutants via their leaves, and the microbes on the leaf surface and within the leaves (endophytes) can biodegrade or transform pollutants into less toxic or non-toxic molecules. Phylloremediation is a natural and environmentally friendly way of removing air contaminants. The term 'phyllo' comes from the Greek word 'phullon', meaning leaf, and so phylloremediation is the process of using leaves and leaf-associated microbes to remove pollutants from the air.

To develop phylloremediation technologies, it is necessary to select and evaluate plant species and microorganisms that are tolerant to pollution and can remove one or more air pollutants. The compatibility of plant leaf surfaces with isolated microbes must then be tested to ensure they work in synergy to reduce pollutants. This testing can take place in laboratories, simulated indoor environments, and outdoor settings.

Once the experimental data has been analysed, phylloremediation technologies can be developed and implemented for remediation of air in both indoor and outdoor environments. The specific plant-microbe combinations that are effective in removing pollutants are identified, and protocols are formulated for evaluating their effectiveness in different settings.

The anatomical, physiological, biochemical, and molecular mechanisms underlying plant responses to each pollutant should also be investigated. Previous research has focused on how plants are injured by pollutants, but further investigation is needed to understand why many plants are tolerant to pollutants, what the underlying mechanisms are, and how these can be manipulated to increase tolerance and improve phylloremediation.

How unhealthy air changes your body and mind

Plants can absorb pollutants, and they are being used to help clean the air in polluted areas. However, the focus of this answer will be on how unhealthy air changes your body and mind.

According to the World Health Organization (WHO), more than 99% of the world's population breathes unhealthy air that exceeds recommended limits for pollutants. Unhealthy air can have profound effects on both physical and mental health.

Physical Health

Air pollution can irritate the eyes, nose, throat, and lungs, causing more frequent and severe asthma attacks, irritation of the eyes and throat, burning sensations in the chest, and reduced lung function. Frequent exposure to air pollution can increase the risk of respiratory diseases, chronic obstructive pulmonary disease (COPD), non-Hodgkin lymphoma, cardiovascular disease, and heart attacks.

Children are particularly at risk from air pollution, with studies suggesting a link between exposure to air pollution and premature birth, as well as potential effects on brain development. Children born and raised in urban areas with high levels of air pollution have a higher chance of developing neurological conditions, behavioral disorders, attention-deficit/hyperactivity disorder (ADHD), and autism spectrum conditions.

Mental Health

There is growing evidence that air pollution affects not only physical health but also mental health. Prolonged exposure to pollutants has been linked to impaired judgment, poorer performance in school, and higher levels of crime. While the relationship is complex and influenced by various confounding factors, researchers are increasingly concerned about the effects of air pollution on brain health.

Additionally, air pollution has been associated with weight gain and the development of related conditions such as type 2 diabetes. Research has found that children living in highly polluted areas are more than twice as likely to be considered obese.

Protecting Yourself from Unhealthy Air

To protect yourself from the harmful effects of unhealthy air, it is important to stay informed about air quality in your area and take appropriate measures. During periods of poor air quality, it is recommended to limit time spent outdoors, keep windows closed, and use air conditioning or air filtration systems. Wearing an N95 mask can also help reduce exposure to harmful particles when spending time outdoors.

Addressing the sources of air pollution, such as reducing emissions from vehicles, power plants, and industrial facilities, is crucial to improving air quality and mitigating the negative impacts on human health.

The best plants to combat indoor air pollution

Plants are nature's air purifiers and can help keep your house clear of air pollution by tackling pollutants such as formaldehyde, benzene, trichloroethylene, and carbon monoxide. Here are some of the best plants to combat indoor air pollution:

Spider Plant

Also known as the air plant, the spider plant is excellent at fighting pollutants such as carbon monoxide, formaldehyde, and benzene. It is very easy to grow and maintain. Just keep it moist in a semi-sunny to a shady spot, and it will thrive.

Aloe Vera

The easy-to-grow aloe vera plant is a sun-loving succulent that helps filter benzene and formaldehyde. It requires a lot of sunlight and little water. You don't need a big space or pot to plant it, and it can be kept near a window to reap its benefits.

Snake Plant

The low-maintenance snake plant, also known as mother-in-law's tongue, is known for filtering formaldehyde, trichloroethylene, xylene, toluene, and benzene from the air. Unlike regular plants, the snake plant absorbs carbon dioxide and releases oxygen at night, making it ideal for keeping indoors.

Bamboo Palm

The bamboo palm, or reed palm, is excellent at removing harmful elements such as benzene and formaldehyde from the air. It prefers part sun or shade, making it a great houseplant.

English Ivy

English ivy is a classically elegant choice that is excellent for removing harmful chemicals found in the home. It can grow in full shade to full sun and can be trained into different shapes. With proper care, it is likely to survive for several years.

Peace Lily

The peace lily is a beautiful plant with lovely white flowers that thrive in average indoor temperatures. It is known to clean the air of alcohols, acetone, trichloroethylene, benzene, and formaldehyde. Keep it moist in a semi-shady location.

Rubber Plant

The rubber plant tolerates dim light and cool temperatures and is excellent at removing air toxins, especially formaldehyde, from any indoor environment. It grows slowly and can reach about 10 feet tall indoors.

Areca Palm

The areca palm is a beautiful and easy-to-care-for plant that removes all indoor air toxins. It also humidifies the air, adding a quart of water a day to your home's humidity. It is especially good at removing toluene and xylene.

Philodendron

Philodendrons are one of the most popular houseplants and excellent air purifiers, removing formaldehyde gases from the air. They are practically bullet-proof plants with quick-growing trailing vines and pretty heart-shaped leaves. They can tolerate full sun to shade if watered regularly.

Chinese Evergreen

The Chinese evergreen is an easy-care plant that thrives in low to medium light and generally grows to 1 or 2 feet. It helps maintain healthy air quality in the home, but it is important to note that it contains an irritant that can be toxic to pets.

Boston Fern

The Boston fern is another great air-purifying houseplant that can help improve the air quality in your home.

Warneck Dracaena

The Warneck dracaena is excellent at combating pollutants that come with paints, detergents, varnishes, and oils. It does not require direct sunlight and can easily grow up to 12 feet in room temperature.

Weeping Fig

The weeping fig likes bright indirect light, high humidity, and warm temperatures. Water it when the top of the soil feels dry, and mist the top regularly.

Chrysanthemum and Gerbera Daisy

If you prefer flowering plants, the chrysanthemum and gerbera daisy are great options. They are effective at removing volatile organic compounds (VOCs) and producing blossoms.

Other Options

Other plants that can help combat indoor air pollution include the bird of paradise, hawthorn, privet, and western red cedar.

Frequently asked questions