Our green friends are also Good Samaritans of the earth. We humans may not bother much about their survival, but they enrich our existence through their very own. That plants in general reduce outdoor pollution is everybody’s knowledge. But few are aware of how they enhance the quality of life indoors too.
In highly industrialised urban lifestyle, more and more people spend longer hours indoors. It is estimated that in the cities people spend almost 90 per cent of their time indoors. Scientific studies in the last several years indicate that the air within offices, homes and other buildings can be more seriously polluted than the air outdoors.
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Contemporary homes and buildings are often tightly sealed to avoid energy loss from cooling or heating systems. The synthetic materials used in modern constructions produce potential pollutants that remain trapped in these poorly ventilated buildings, and these pollutants result in what is often called the Sick Building Syndrome (The condition in which occupants of a building experience health hazards).
Pollution sources that release gases or particles into the indoor air are the primary cause of air quality problems in buildings. Inadequate ventilation, high temperature and humidity levels can increase concentrations of the pollutants.
Many of the volatile organic compounds (VOCs), which are emitted as gases from wide range of solids or liquids, cause short-term and long-term adverse health effects. Concentrations of the VOCs may be ten to thousand times higher indoors than outdoors. The pollution sources include - paints, paint removers, pesticides, building materials and furnishings, televisions, gas stoves, copiers, printers, computers, correction fluids, glues and adhesives, permanent markers, wood preservatives, cosmetic sprays, tobacco smoke, disinfectants and air fresheners, wall and floor coverings, plastic products, synthetic fabrics, upholstered furniture, central heating and cooling systems, compressed and laminated wood products and so on.
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While pollutant levels from individual sources may not pose a significant health risk by themselves, most homes have more than one source that contributes to indoor air pollution. There can be a serious risk from the cumulative effects of these sources.
Health effects
There are more than 900 identified VOCs that may pose acute and chronic health problems to individuals who live and work inside the buildings. The extent and nature of the effects depend on many factors including level and duration of exposure. Eye and respiratory tract irritation, headaches, fatigue, dizziness, skin allergies, visual disorders, and memory impairment are among the immediate symptoms that people may experience soon after exposure to some VOCs. Some of these organic compounds can cause long term health problems such as asthma while some are even carcinogenic.
Role of plants
Scientific studies show that plants play an important role in cleaning the air we breathe, both indoors and outdoors. Plants are known to clean the air through their food processing called photosynthesis. In the process, they clean the air by absorbing carbon dioxide, and by releasing lifesaving oxygen into the air. Plants are also proven to be effective in absorbing certain VOCs and reducing dust accumulation.
A team of National Aeronautics and Space Administration (NASA) scientists led by Dr. Bill Wolverton tested the effect of house plants on the three major indoor air pollutants - Benzene, Formaldehyde and Trichloroethylene. Formaldehyde is used in many building materials and cleaning products where as Benzene and Trichloroethylene are found in oils, paints, adhesives, inks and varnishes.
Plants clean air
Research has proved that certain plants could be effective in abating indoor air pollution. These are common indoor foliage plants which are easily available in local nurseries. In the NASA study, certain houseplants were found to remove about 87 per cent of indoor air pollutants within 24 hours. Scientists suggest that for the plants to be effective, it is necessary to use one potted plant per 100 square feet of home or office space. They also recommend that the plants be grown in six-inch containers or larger for more leaf area.
These exciting revelations in the last few decades have helped us realize that a house plant, valued for its aesthetic value, quietly but efficiently works in the background to enhance our well-being. Hence we can rest assured that plants within built spaces help to soothe and calm our senses and purify and refresh the air we breathe.
(The author is a forest officer, presently Additional Commissioner (Parks) in GHMC and can be contacted at ‘nchandramohanreddy@gmail.com’)