M odern anthropogenic activities have contaminated the quality of air and lead to air pollution, air quality within and around buildings and sealed environments, which relates to the health and convenience of the building inhabitants is known as the Indoor air quality (IAQ). IAQ can be contaminated by gases, including, carbon monoxide, radon, volatile organic compounds (VOC), particulates, microbial contaminants (mold, bacteria), or any mass or energy stressor that can induce adverse health conditions (Jones, 1999).
In modern habitations, cooking and heating requirements are usually met by fossil fuels such as natural gas, liquefied petroleum gas, heating oil (petroleum product) and electricity. The gases and pollutants emitted from the burning of these fossil fuels deteriorates the indoor air quality. When we talk about of air pollution, we consider smog, power plants and emissions from cars and trucks. However these are examples of outdoor air pollution, but air indoors can be polluted, too. Pollutants are any harmful contaminants in the air; therefore, indoor air pollution occurs when pollutants from furnishings, fossil fuel combustion, cooking and heating equipments release poisonous gases and particles that adulterate the air indoors. Indoor air pollution is a very real and dangerous thing because indoor air is far more concentrated with pollutants than outdoor air. It’s estimated that 2.2 million deaths each year are due to indoor air pollution (compared to 500,000 deaths from outdoor air pollution) (Von Schirnding et al, 2002).
For example, the fossil fuels are a source of occasional carbon monoxide poisoning because of improper use or insufficient airing of appliances. The gas stoves in indoor settings lead to exposure to nitrogen dioxide (NO2) which is also one of the indoor air pollutants (Basu, 1999). Gaseous fuels in simple devices emit substantially smaller amounts of pollution, including particulate matter (PM), CO, eye irritating volatile organic compounds (e.g. aldehydes), and carcinogenic compounds such as benzene and 1,3-butidiene and polycyclic aromatic hydrocarbons (Zhang et al, 2000). The indoor air pollutants have been compiled in the Table 1 below.
Table 1: Major health-damaging pollutants generated from indoor sources (Zhang, 2003)
*Pb-containing dust from deteriorating paint is an important indoor pollutant for occupants in many households, but the most critical exposure pathways are not usually through air.
Harmful impacts of modern house hold items
People in modern dwellings spend about 90% in indoor environments, which has a significant impact on public health and well-being (Leech et al, 2002). Modern house hold items like humidification devices, cooking stoves, carpets, refrigerators, combustible items (kerosene, oil, coal, wood and tobacco), paints, building material (asbestos) and central heating and cooking appliances are associated with numerous health risks caused due to the biological and chemical contaminants emitted by them (Žuškin, 2009). Some of the sources and potential health effects of indoor air pollutants have been discussed below:
|Pollutant||Indoor sources||Potential health effects|
Cigarette and cigar smoke, unventilated or malfunctioning gas appliances, wood stoves, tobacco smoke, cooking gases, gas heaters, formaldehyde, volatile organic compounds, odors, products for household cleaning and maintenance, combustion pollution, aerosol sprays, solvents, glues, cleaning agents, pesticides, paints, moth repellents, air fresheners, dry-cleaned clothing, treated water, products used to kill pests such as insecticides and herbicides. Also lawn and garden products, pressed wood products such as plywood and particleboard; furnishings; wallpaper; durable press fabrics.
Pneumonia in children
Loss of coordination
Damage to central nervous system
Various types of cancer
|Eye, nose and throat irritation, increased susceptibility to respiratory infections and bronchitis, lung cancer, asbestosis, mesothelioma||Eye, nose and throat irritation,
Increased susceptibility to respiratory infections and bronchitis,
|Soil under buildings, some earth-derived construction
|Lead||Sanding or open-flame burning of lead paint; house dust||Nerve disorders,
Damage of kidney,
|Biological organisms and other organic pollutants||House dust, dust mites, pets, bedding; poorly maintained air conditioners, humidifiers and dehumidifiers, wet or moist structures, furnishings, insects, cockroach parts, pollen, animal dander and saliva, protein in animal urine, bacterial endotoxins and fungal materials||Coughing,
Shortness of breath,
Eye, nose, and throat irritation,
Simple ways to reduce indoor air pollution
- Maintain a healthy level of humidity indoors
Moisture attracts dust mites and molds. Maintaining optimum humidity levels (30%-50%) keeps them and other allergens away. A dehumidifier (AC during summers) brings down the moisture effectively. Simple ways to dehumidify indoor air are:
- Avoid over-watering indoor plants
- Always use exhaust fan and keep all the windows open while cooking, when running a dishwasher, or while bathing
- Fix leaking plumbing
- Keep the floors fresh and dry
- Use HEPA filter vacuum: By using a vacuum with a HEPA filter you can reduce concentrations of lead in your home. You can also get rid of other toxins, like brominated fire-retardant chemicals (PBDEs) as well as allergens like pollen, pet dander, and dust mites.
- Mop it up: Proper mopping removes dust which vacuuming leaves behind hence removing allergens
- Keep a door mat outside: A door mat reduces the amount of dirt, pesticides, and other pollutants from getting into your home. If the mat is big enough, even those who don’t wipe their shoes will leave most pollutants on the mat — not the floors in your home.
- Prevent problems
To discourage dust mites, encase your pillows, mattresses, and box springs in dust-mite-proof covers. Wash very dirty or dusty laundry in the hottest water.
- Make your home no smoking zone
Don’t smoke or allow others to do so in your home or car.
- Control critters
Seal cracks and crevices and put food away. You’ll be less apt to attract pests and need to use pesticides. To minimize your exposure to pet dander, banish pets from sleeping areas and upholstered furniture.
Role of indoor plants in mitigating indoor air pollution
When we inhale, oxygen finds its way into our lungs and while exhaling, we release carbon dioxide. During photosynthesis, plants do the opposite. They absorb carbon dioxide and release oxygen, making plants and people great partners when it comes to gases. Plants help to increase oxygen levels, and our bodies appreciate that. However, a few special plants – like orchids, succulents and epiphytic bromeliads – flip this process and take in carbon dioxide and release oxygen. Meaning, accommodating these plants indoors helps to keep the oxygen flowing at night.Plants are the lungs of the earth: they produce the oxygen that makes life possible, add precious moisture, and filter toxins. Houseplants can perform these essential functions in your home or office with the same efficiency as a rain forest in our biosphere.
Indoor plants apart from transforming the environment in the house into more positive space and being just objects of decor, serve other purposes as well like reducing carbon dioxide levels and concentration of indoor air pollutants such as benzene and nitrogen dioxide (Taran, 2007). Some of the common indoor plants act as valuable weapons to combat rising levels of indoor air pollution. NASA scientists, after extensive research have discovered that both plant leaves and roots play a role in absorbing trace levels of toxic vapors and poisonous gases moving freely in sealed environments (Concrete houses, buildings, offices).
Formaldehyde, organic compounds (benzene and trichloroethylene or TCE), carbon monoxide, radon, nitrogen oxides and some biological pollutants are the potential indoor air pollutants that affect health. These pollutants trigger ‘sick building syndrome’, which results in symptoms like allergies, headaches and fatigue, nervous-system disorders, cancer and sometimes even death. An indoor plant’s ability to remove these harmful compounds from the air is an example of phytoremediation, which is the use of any plant — indoors or out — to mitigate pollution in air, soil or water. The microorganisms that live in the soil of potted plants also play an instrumental role in neutralizing Volatile Organic Compounds and other pollutants.
Plants also appear to reduce airborne microbes, molds, and increase humidity (Wolverton, 1996)
NASA, with assistance from the Associated Landscape Contractors of America have identified 50 household plants that possess the ability to remove toxic air gases in sealed environments (Wolverton, 1989).
Breathe Clean – Top ten plants for removing pollutants from air
Top ten plants for removing formaldehyde, benzene, and carbon monoxide from the air are:
Peace Lily (Spathiphyllum “Mauna Loa”)
Chinese Evergreen (Aglaonema modestum)
Dracaena “Janet Craig” (Dracaena deremensis)
Philodendron (Philodendron sp.)
Areca Palm (Chrysalidocarpus lutescens)
Lady Palm (Rhapis excelsa)
Bamboo palm (Chamaedorea seifrizii)
Rubber Plant (Ficus robusta)
Weeping Fig (Ficus benjamina)
Boston Fern (Nephrolepis exaltata “Bostoniensis”)
Breathe Clean – NASA Clean Air Study, Suggested Plants
1. English Ivy (Hedera Helix)
The English Ivy is ideal for pots because its invasive nature allows it to spread easily. Research found it to be particularly useful in eliminating airborne fecal-matter particles. The plant is also great for a family with smokers in it. Its ability to soak up carcinogens from second-hand smoke helps to purify small areas. It’s also versatile when it comes to growing conditions and doesn’t require much maintenance.
2. Golden Pathos (Epipremnum Aureum)
NASA considered this plant one of the most effective choices for eliminating formaldehyde. People that have struggled to keep plants alive can rejoice – this one is incredibly hard to kill. It doubles as an effective eliminator of carbon monoxide as well. The vines grow fairly quickly and look great suspended from elevated areas.
3. Boston Fern (Nephrolepis Exalta Bostoniensis)
This lush plant functions really well as a natural air humidifier. While it’s busy adding humidity to the environment it also does a great job eliminating formaldehyde. It’s large feathered ferns span as large as 5 feet and allow just a single plant to have a noticeable impact.
4. Dracaena (Dracaena Deremensis)
The long striped leaves of this plant can easily thrive indoors with only small amounts of sunlight and moderate watering. It’s an excellent way to eliminate trichloroethylene that comes from solvents and varnishes. A single plant can grow over ten feet tall, but pruning will keep it short if you prefer.
5. Bamboo Palm (Chamaedorea Seifrizii)
The Bamboo Palm can easily fit into smaller areas with indirect lighting. NASA found it to be one of the best air filters for benzene and trichloroethylene, and a great humidifier. This palm is a bit smaller than others and easy to grow in shady areas. It releases a good deal of moisture into the air and is considerably resistant to insect infestation.
6. Dragon Tree (Dracaena Marginata)
This plant is a widely popular option for office spaces and homes for its attractive look and effective purifying power. It pulls xylene – a chemical released from car exhaust, paints, and cigarettes – from the air with little need for maintenance. It can also be potted together and trained to grow into a braid for visual appeal and added purification.
7. Peace Lily (Spathiphyllum)
The Peace Lily is one of the most visually appealing plants on the list with its unique white flowers. It boasts one of the highest transpiration rates on the list as well. Use it to remove formaldehyde, trichloroethylene, benzene, acetone, and alcohols from the air.
8. Florist’s daisy (Chrysanthemum Morifolium)
Florist’s daisy (Chrysanthemum Morifolium) is a variety of mums (Chrysanthemum), it is very hardy plant which is found all over the world at florist shops because of its unlimited exotic flowers color, shade and size variations. One of the worlds most sold flower is native to Asia and it is one of the “Four Gentlemen” of China (the others being the plum blossom, the orchid, and bamboo). Chrysanthemum morifolium is very effective plant for purifying the environment.
9. Lady Palm (Rhapis Excelsa)
The Lady Palm requires a lot of watering during the spring and summer but makes up for it with its heavy resistance to insects. The lush leaves of this palm grow thick and with rich color without much effort. It’s said to be a versatile and effective filter for multiple indoor pollutants.
10. Spider Plant (Chlorophytum Comosum)
The Spider Plant requires natural light but shouldn’t be exposed directly to the sun. It thrives in moist environments with bi-weekly watering and grows at impressive speeds. Owners prefer to place these plants near the fireplace and kitchen where carbon monoxide may build.
11. Snake Plant (Sansevieria Trifasciata)
The Snake Plant is unique in that it sucks in carbon dioxide and releases oxygen during the night. Many people chose to keep it in their bedroom or carpeted living room. It’s simple to take care of and prevents the formaldehyde that leaks from your carpet and wood furniture from sticking around the air.
12. Ficus (Ficus Benjamina)
The Ficus tree is one of the more common indoor plants, and is typically found in offices across the country. The appearance resembles an outdoor tree, which is why this is one of the more popular choices. It’s good at removing toxins from the air, and has been proven to remove airborne formaldehyde and other poisons. You may find that the plant outgrows the area you’ve designated for it, at which point it will need to be pruned down to size.
13. Moth Orchid (Phalaenopsis)
Moth Orchids are especially good at taking care of xylene and toluene, two chemicals that generally find their way into homes due to the large number of household items that contain them. Everything from fingernail polish to glues, paint to paint thinner could have xylene and toluene in them. This means it’s extra important to have plants that can clean up the air making it safer to breath.
14. Barberton Daisy (Gerbera Jamesonii)
These daisies will surely brighten your day when they’re in bloom, and the rest of the time the plant itself will be hard at work keeping your air clean. They’re effective at cleaning up three different indoor pollutants, and whether or not you notice an immediate difference, your air will be cleaner, which makes a big difference over the long term.This is an indoor/outdoor plant that you’ll want to place outdoors during the summer so that it can get the most sunshine.
15. Cornstalk Dracaena (Dracaena Fragrans)
This plant is aptly named and resembles a cornstalk, while still maintaining an attractive enough appearance to add to the decor of your home. You’ll be happy it’s there, because it will be helping to remove benzene, formaldehyde, and trichloroethylene from inside your home.
16. Pleomele (Dracaena Reflexa)
Here’s a pretty plant that would love a spot in your home. It’s also known as Song of India and has a very distinct look to it. This is one plant that you don’t want to miss out on, as it has been proven to be one of the best at removing several different indoor toxins, including xylene and trichloroethylene.
17. Aloe vera (Aloe Vera)
Aloe vera is a medicinal plant which has outstanding significance from ancient times, it is mentioned at several medical science manuscripts, it has effective healing power and majorly used in beauty products. Aloe vera plant is very hardy and it can survive in difficult weather conditions without stress and hampering its work of removing the toxins like formaldehyde and benzene.
18. Banana (Musa Oriana)
Banana is known as one of the religious plants which is worshiped. Banana is very effective plant and used to fulfill various human needs like food, beauty, shelter as well as purifying the air.
19. Flamingo lily (Anthurium Andraeanum)
Anthurium andraeanum is also known as valentine plant, its beautiful heart shape leaves and flower appear very attractive. Anthurium is easy care plant and does very well in indoors environment. It is found quite effective in removing formaldehyde, xylene, toluene, and ammonia from the air.
20. Chinese evergreen (Aglaonema Modestum)
Aglaonema is an outstanding indoor plant, it is one of the most commercially cultivated plants and found in almost every house, it also does a great job eliminating formaldehyde. Aglaonema has 150+ extremely elegant hybrid varieties of different shapes, shades and colors. Aglaonema is also known as Chinese evergreen because of its origin in South Asia.
Read More on NASA Test – Click Here
Basu, R. S. J. M., & Samet, J. M. (1999). A review of the epidemiological evidence on health effects of nitrogen dioxide exposure from gas stoves. Journal of environmental medicine, 1(4), 173-187.
Jones, A. P. (1999). Indoor air quality and health. Atmospheric environment, 33(28), 4535-4564.
Leech, J. A., Nelson, W. C., Burnett, R. T., Aaron, S., & Raizenne, M. E. (2002). It’s about time: A comparison of Canadian and American time–activity patterns. Journal of Exposure Analysis & Environmental Epidemiology, 12(6).
Orwell, R. L., Wood, R. L., Tarran, J., Torpy, F., & Burchett, M. D. (2004). Removal of benzene by the indoor plant/substrate microcosm and implications for air quality. Water, air, and soil pollution, 157(1-4), 193-207.
Tarran, J., Torpy, F., & Burchett, M. (2007, October). Use of living pot-plants to cleanse indoor air–research review. In Proceedings of 6th Internet Conf. On Indoor Air Quality, Ventilation & Energy Conservation,-Sustainable Built Environment (pp. 249-256).
Von Schirnding, Y., Bruce, N., Smith, K., Ballard-Tremeer, G., Ezzati, M., & Lvovsky, K. (2002). Addressing the Impact of Household Energy and Indoor Air Pollution on the Health of Poor: Implications for Policy Action and Intervention Measures. Geneva: World Health Organization.
Wolverton, B. C., Johnson, A., & Bounds, K. (1989). Interior landscape plants for indoor air pollution abatement. NTRS, NASA John C. Stennis Space Center, Bay Saint Louis, MS, United States).
Wolverton, B. C., & Wolverton, J. D. (1996). Interior plants: their influence on airborne microbes inside energy-efficient buildings. Journal of the Mississippi Academy of Sciences, 41(2), 99-105.
Zhang, J., Smith, K. R., Ma, Y., Ye, S., Jiang, F., Qi, W., & Thorneloe, S. A. (2000). Greenhouse gases and other airborne pollutants from household stoves in China: a database for emission factors. Atmospheric Environment, 34(26), 4537-4549.
Zhang, J. J., & Smith, K. R. (2003). Indoor air pollution: a global health concern. British medical bulletin, 68(1), 209-225.
Žuškin, E., Schachter, E. N., Mustajbegović, J., Pucarin-Cvetković, J., Doko-Jelinić, J., & Mučić-Pucić, B. (2009). Indoor air pollution and effects on human health. Periodicum biologorum, 111(1), 37-40.