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A reduction in CO² and increase in O² with the use of indoor plants results in up to 70% higher awareness of staff and a 12% increase in productivity specifically in terms of computer related tasks.
6 Bottom Line Benefits of Interior Landscaping
Plants offer a means to decrease stress while enhancing productivity by twelve percent.
According to Wayne Hansen, a member of Cal-OSHA and an editor for CAHO publications, human assets are the most valuable and expensive assets of any business. In terms of cost/square foot, the human asset is approximately 10 times the total building operation cost and nearly 100 times the energy cost. No matter how it is expressed, when a business can give rise to personal productivity, the business wins.
It is widely known through the respected research done by Dr. Roger S. Ulrich of Texas A & M University, Helen Russell, Surrey University England as well as the recent studies conducted by Dr. Virginia Lohr of Washington State University that plants significantly lower workplace stress and enhance productivity.
In Dr. Lohr’s study participants were 12 percent more productive and less stressed than those who worked in an environment with no plants. The study took place in a stimulated office setting. Common interior plants were used in a computer laboratory with 27 workstations. A computer program to test productivity and induce stress was specifically designed for these experiments which incorporated one hundred symbols and time-measured readings of participants’ reactions. They were presented in the same randomized sequence to each subject. Blood pressure readings recorded while using the program confirmed the program was effective in inducing stress.
Emotional states and pulses were also measured during the experiment. Plants present and plants not present were the only variables that participants experienced. When plants were present, they were positioned so that a cluster would we in the peripheral view of each subject sitting at a computer terminal, but would not interfere with the subject’s activity. In addition to demonstrating significant increases in their post-task attentiveness, subject reaction time in the presence of plants was 12 percent faster than those in the absent of plants.
The results indicating an influence of plants on blood pressure are consistent with research conducted by Dr. Ulrich. Visual exposure to plant settings has produced significant recovery from stress within five minutes.
As many performance based incentives to enhance employee productivity also give rise to stress, the rare capability of raising productivity while lowering stress is extremely valuable. Progressive human resource executives are finding they cannot afford to ignore such an efficient method of human asset management.
Interior Plants lower O & M (Operations and Maintenance) costs while contributing to "Green Building" design considerations.
Plants cool by a process called transpiration, which, according to the U.S Department of Agriculture, decreases air temperature in offices by ten degrees. A recent study out of Washington State University demonstrates that plant transpiration in an office, environment releases moisture, creating a humidity level exactly matching the recommended human comfort range of 30-60 percent. Similarly, the same study concludes that in an absence of plants, the relative humidity in offices runs below this recommended range. When the relative humidity of office air is too low, costly materials such as wood become damaged and crack. When the relative humidity is too high the condensation of windows and exterior walls can result in costly structural damage.
According to the International Society of Arboriculture, the net cooling effect of one young, healthy tree is equivalent to ten room-size air conditioners operating 20 hours a day. According to literature from the Associated Landscape Contractors of America, proper selection and placement of plant materials can lower heating and cooling costs by as much as 20%. These statistics have become an important tool for today’s environmentally efficient corporate designers and facility managers such as U.S Energy Systems Inc. This growing energy company is enthusiastically endorsing the use of indoor plants. Susan Osiseos, V.P. of Corporate Communications states " We practice what we preach and find that our investment in interior plants service has had the expected outcome of improving indoor air quality, supporting a positive outlook in the workplace and increasing employee productivity." She continued "interior plants are a solid return on investment and a MUST for any corporation concerned with sustainable, "green building" solutions."
The advantages of outsourcing interior landscaping services are readily apparent and can be measured in visual and bottom-line advantages to the property. Richard Greninger, managing director of Carr America Realty Corporation (with 326 Buildings in fifteen markets) claims that through outsourcing these services, "live plantscape have become a value-added distinguisher, defining our first class brand identity."
Plants in the workplace attract, retain and enhance attitude of today’s selective employee
Survey’s conducted by Unifi Network, Westport, Conn. report numerous factors that assist in managing today’s competitive workplace market. The data indicates that in order to attract and retain top employees, the workplace must include aspects of what inspires employees during "off" time. Gallop polls indicate that two thirds of the American working force, cite gardening as their favorite hobby. Perhaps this "green thumbs" passion explains why humanizing the workplace with green plants is a highly effective method to promote employees satisfaction. Copious studies such as those conducted by Dr. Ulrich and Dr. David Uzzell from Oxford University verify the positive effect plants have on employee perception and disposition. In the final analysis, marketing research (Krome Communications, 2000) confirms that employee attitude and retention is a top incentive for corporations to continue interior landscape contracts.
The dramatic aesthetic value inherent in indoor landscaping has continued to be the number one return on interior plant investments.
As reflected in The 2001 BOMA/CEL Tenant Satisfaction "A-List Award" (Building Owners and Managers Association), "appearance and condition of the property" is a top category of evaluation among tenants. Similarly, studies out of England’s Oxford Brooks University reinforce that while indoor plants continue to cost less than most alternative corporate décor choices, they offer a guarantee of positively enhancing perception and contributing to well being. The same set of studies conclude that people (clients or employees) perceive a building with interior planting as more expensive looking, more welcoming and more relaxed. Conversely the studies prove that people’s perceptions of a building are less positive in the absence of plants. Melissa Casey, V.P., Brookfield Financial Properties, is a corporate interior plant enthusiast. She asserts that the vast plantscaping throughout Brookfield’s property "provide a critical elegance to this bustling business setting of 40,000 corporate employees".
It’s finally possible to have an energy efficient building without "Sick Building Syndrome!" Plants help with bottom line savings on mounting sick leave expenses.
"Sick Building Syndrome" develops into a serious and expensive liability when these toxins become concentrated inside sealed office buildings. NASA reports that the syndrome is widespread in these energy efficient buildings. The problem is that these sealed energy efficient buildings have less exchange of fresh outdoor air for stale indoor air. This causes higher concentrations of toxic chemicals in indoor environments, brought about by emissions from a great variety of building constituents. As energy efficient construction becomes absolutely essential, "green building" designers have become justifiably concerned about this indoor air quality (IAQ) dilemma. Perhaps one of the most troubling reports comes from research published by Bio-Safe Incorporated (New Braunfels, Texas). Their data confirms that energy efficient, sealed office structures are often 10 times more polluted that the air outside!
Research shows that plant-filled rooms contain 50-60 percent fewer airborne molds and bacteria than rooms without plants. For almost twenty years Dr. Billy C. Wolverton and his aids in the Environmental Research Laboratory of John C. Stennis Space Center have been conducting innovative research employing natural biological processes for air purification. "We’ve found that plants have been found to suck these chemicals out of the air," he says. "After some study, we’ve unraveled the mystery of how plants can act as the lungs and kidneys of these buildings." The plants clean contaminated office air in two days. They absorb office pollutants into their leaves and transmit the toxin to their roots, where they are transformed into source of food for the plant. In this book, How to Grow Fresh Air: 50 Houseplants That Purify Your Home of Office (Penguin, 1997), Dr. Wolverton details exactly how plants emit these water vapors that create a purifying action to pull dirty air down around the roots, where it is once again converted into food for he plant.
Wolverton has found that plants are especially needed in office buildings in which sick building syndrome is common. He goes so far as to suggest that everyone have a plant on his or her desk, within what he calls the "personal breathing zone." This is an area of six to eight cubic feet where you spend most of your working day. Jay Naar, author of Design for A Livable Planet, suggests 15 to 20 plants are enough to clean the air in a 1,500 square foot area.
Plants help reduce distractions due to office noise.
Strategically placed, plants quiet down an office. A small indoor hedge around a workspace will reduce noise by 5 decibels. The positive contribution of interior plants to sound absorption has been well documented in numerous studies including the work done by Dr. Helen Russel, Oxford, England and David Uzzell, University of Surrey, England. Although it would be difficult to measure the cost of productivity loss due to office noise pollution, one doesn’t have to go far to find examples! Almost anyone who walks in an office can give account to being "annoyed" into taking a break due to the common audible elements of a busy office. According to the Associated Landscape Contractors of America, landscape professionals are replacing stale cubicles for "tree walls" and other innovative plant groupings to reduce this costly "decibel distraction factor."
Interior Plants play a critical role in reducing stress throughout corporate America.
Interior Plants play a critical role in reducing stress throughout corporate America.
Recent research information by Integra Realty Resources of New York and Opinion Research Corp International of Pinetown, N.J, indicates that the American workplace is showing signs of a collective "nervous breakdown" and security uncertainties and the current economic environment are placing added stress on workers. When stress escalates employers report greater turnover and absenteeism and lower productivity
Visual exposure to a plant setting has produced significant recovery from stress within five minutes while enhancing productivity by 12 percent, according to a study by Texas A & m University and Washington State University (WSU). WSU research also confirms that once exposed to plant settings, test participants demonstrated more positive emotions, such as happiness, friendliness and assertiveness as well as fewer negative emotions, such as sadness and fear.
Researchers conclude that interior workplace plants signal stability and offer employees a touch of humanity while stimulating a more productive environment. To learn more about plants, go to www.plantsatwork.org, which is sponsored by the Associated Landscape Contractors of America.
Trees and shrubs have been used for many years to reduce traffic noise from busy roads. Research now shows that plants can also help to reduce background noise levels in buildings.
Trees and shrubs have been used for many years to reduce traffic noise from busy roads. Research now shows that plants can also help to reduce background noise levels in buildings. Some plant species are more effective than others and the benefits are most pronounced in buildings with hard, reflective surfaces.
Tests carried out by Rentokil Initial Research and Development suggested that interior plants can absorb or reflect background noise in buildings, thereby making the environment more comfortable for the occupants. The effect appears to be dependent on plant type, planting density, location and sound frequency.
To investigate the potential acoustic benefits of interior plants in more detail, further research was carried out by a post-graduate student, Peter Costa, at South Bank University, London. Rentokil supported this work by providing access to computer data banks, technical advice, plant specimens and test sites.
To quantify the acoustic effect, the sound absorption coefficients of a number of plant species were measured and compared with other building materials (see table).
The higher the absorption coefficient, the better the material is at absorbing sound – a coefficient of 0.25 means that a quarter of the sound is absorbed, 0.50 half the sound and so on.
| Plant Species | Sound Frequency | |||||
| 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz | |
| Ficus benjamina | 0.06 | 0.06 | 0.10 | 0.19 | 0.22 | 0.57 |
| Howea forsteriana | 0.21 | 0.11 | 0.09 | 0.22 | 0.11 | 0.08 |
| Dracaena fragrans | 0.13 | 0.14 | 0.12 | 0.12 | 0.16 | 0.11 |
| Spathiphyllum wallisii | 0.09 | 0.07 | 0.08 | 0.13 | 0.22 | 0.44 |
| Dracaena marginata | 0.13 | 0.03 | 0.16 | 0.08 | 0.14 | 0.47 |
| Schefflera arboricola | - | 0.13 | 0.06 | 0.22 | 0.23 | 0.47 |
| Philodendron scandens | - | 0.23 | 0.22 | 0.29 | 0.34 | 0.72 |
| Bark mulch | 0.05 | 0.16 | 0.26 | 0.46 | 0.73 | 0.88 |
| Thick pile carpet | 0.15 | 0.25 | 0.50 | 0.60 | 0.70 | 0.70 |
| Plasterboard | 0.30 | 0.15 | 0.10 | 0.05 | 0.04 | 0.05 |
| Fresh snow, 100mm | 0.45 | 0.75 | 0.90 | 0.95 | 0.95 | 0.95 |
The study indicates that plants are generally more efficient at absorbing high sound frequencies than low. Good examples of this are Spathiphyllum wallisii (Peace Lily), Philodendron scandens (Sweetheart Plant), Dracaena marginata (Madagascan Dragon Tree) and Ficus benjamina (Weeping Fig).
High frequencies cause the most irritation to building occupants so the benefit of having plants becomes clear.
The noise-reducing benefits of plants will be most pronounced in acoustically "live" buildings, i.e. those with hard reflective surfaces such as marble floors, plaster walls and large expanses of glass. Plants will have very little effect in acoustically "dead" areas, such as rooms with thick carpets, curtains and panelled walls.
In addition:
Bigger planters have more mulch and more plants. It follows that they make a larger impact on room acoustics. Arrangements comprising different plants in groups of three or five appear to work better than individual plants.
Positioning several arrangements around a room would work better than concentrating the planting in one location. This way the surface area of the plants exposed to the noise may be maximised.
Near the edges and corners would be better than in the centre of a room. In these positions sound reflected from walls may be intercepted more easily by the plants.
Source: www.interiorscape.com
'Living Machines' processing cosmetic waste water from Body Shop products.
Plants are taking us back to our roots and helping to prove that the ecological way is a functional option, which saves energy and water. Evidence of this can be seen at Watersmead in Littlehampton where COSI manufacture some products for the Body Shop. Here, a 'Living Machine' processes waste materials naturally.
Plants can bring positive benefits to our lifestyles now and in the future. Processing waste matter, which is the function of a Living Machine, is only one area where plants can help, but it is an important one as it helps reduce the impact on our environment and prepares water for recycling.
Microbes living in the root systems of plants extract the chemicals from the effluent and use it to feed the plant's roots. In this way, waste matter is processed and cleaned naturally. The cleaned water, known as grey water, can then be used to water plants or flush toilets.
At the Watersmead cosmetic manufacturing plant in Littlehampton, the grey water from the Living Machine, installed to recycle commercial wastewater from the manufacture of The Body Shop products, is fed to the sewers.
The Living Machine at Watersmead is believed to be the first installation of its kind by a cosmetics company anywhere in the world. It was established in 1991 to process commercial waste used in the manufacture of the cosmetics.
The Watersmead Living Machine was especially adapted to process The Body Shop wastewater materials. The eco-system which processes the waste is contained in two identical parallel 'trains' of eight tanks in an insulated greenhouse. The effluent takes up to five days to pass through the system.
Before it enters the eco-system, the effluent enters a filtration tank, which removes particles and oils. Once in the system, the waste is split between the two trains for processing.
The first two tanks in the trains contain natural aquatic bacteria in vast numbers which slowly break down the organic pollutants using the carbon freed in the process to reproduce and increase their own bio-mass.
When the effluent enters the third tank, it is clean enough to allow the growth of some hardy species of aquatic plants. It is the micro-organisms that live in the root zones of these plants, which process the pollutants in this tank.
By the fifth tank, the water is clean enough to support five or six plant species, which continue the cleaning process through the micro-organisms in their root zones.
After approximately four days in the system, the waste reaches the last stage in the treatment process. By now, almost all of the dissolved organic pollutants have been broken down. Even at this stage, the waste is still cloudy with bacterial matter but now, the particles settle at the bottom of a small clarification tank. Bacterial sludge is removed automatically once an hour; half is recycled into the first tank to re-seed the system, and half is returned to the ultra-filtration system for processing.
The water is now suitable for discharge but before it leaves the Living Machine it must undergo a further half-day biological filtration in a special tank known as an Ecological Fluidised Bed. Here it is rapidly re-circulated through a column of recycled blast-furnace slag, a perfect habitat for bacterial slimes, algae, worms, snails and waterfleas which consume any of the remaining fine particles of bacterial 'floc'.
When the waste is finally discharged into the sewer, it contains less than ¼ of 1% of its original pollutants and less than 1% of its original detergent content.
With growing concern from various well-respected bodies about the speed with which we are devouring natural resources, it is little wonder that we are returning to a reliance on the natural environment. Grey water recycling and Living Machines follow the trend to care for the earth and extend its natural life support systems.
Alex Walker of international company, Living Technologies who are responsible for several Living Machines in the UK commented, "Although we are some way behind our Continental neighbours and the USA, awareness for green issues is rising, particularly in the private sector."
As more and more businesses take heed and look to natural ways to improve their working environments and waste management, so plants will play a big part in shaping this new future for buildings and not just in Living Machines. Planted interiors will help improve humidity levels and noise absorption, reduce the symptoms of minor ailments and by implication, absenteeism, reduce stress levels thereby increasing productivity.
The latest Living Machine to be installed is at Earth Works in Doncaster. Other Living Machines can be found at:
Indoor plants have their set place in many flats, offices and companies. People intuitively feel that the contact to plants and nature have a calming effect on them. Many are also of the opinion that productivity and satisfaction of workers increases, if the place of work has indoor plants incorporated.
Indoor plants have their set place in many flats, offices and companies. People intuitively feel that the contact to plants and nature have a calming effect on them. Many are also of the opinion that productivity and satisfaction of workers increases, if the place of work has indoor plants incorporated. Up until now there was no scientific proof of this assumption, but now the assumption has been supported by a study carried out by the Washington State University. Ever since urbanisation, we spend more time indoors - over 90 per cent - for example in the office and at home. The indoor climate is of eminent importance for our health and our well-being. Above this: when our work becomes technically more complex, the amount of illnesses caused by stress increases. Due to this fact it is important and sensible to study the relationship between plants and the well-being of humans. Up until now there were only definite studies that underlined the above mentioned assumptions that plants are good for a healthy indoor climate and increase the well-being and the productivity of work. In early studies, that measured the effects of plants by measuring employees' blood pressure, the test persons were shown videos of plants in their natural environment. The result: the test persons, that were put under stress and that were shown plants, lessened stress faster than those who had a view onto concrete and walls.
A study, carried out in 1995 by the faculty of Horticulture and Landscape Architecture of the Washington State University and led by Dr. Virginia Lohr, on the effects of indoor plants on the office climate and the well-being of employees, proved that indoor plants in offices for one reduce stress and for the other helped to increase productivity. In this experiment the blood pressure, the heart frequency and the emotional condition of 96 test persons - mainly young men and women - was controlled. The students, but also the employees of the university were in a computer room with bare walls and no daylight for the duration of the test. All test persons were experienced in the running of computers. 81 per cent of the test persons answered that they liked plants; the rest had either no opinion or did not like plants. 66 per cent had plants at home or in the office.
Another factor decisively contributes to productivity at work: the speed of reaction. In order to be able to measure this by the test persons, a special computer programme was designed for the study, which created stress by the test persons and at the same time measured productivity. Such measurements of the speed of reaction by which test persons had multiple choice options, gave a clear picture about the mental complex functioning. For this reason they are valid as suitable means of measurement for the testing of productivity under stress, respectively tiring, conditions. The programme shows a picture on the screen selected from a range of three pictures. The test persons were told to press the key respective to the picture as soon as they had recognised the picture.
The test persons were to complete the computer tasks in two different situations: with and without plants. The plants were integrated into the test rooms in such a manner that they were visible for all test persons without distracting them from their task. After the experiment the measurements of test persons were compared with both situations. The results were clear: people in the rooms with plants were of the opinion to have been more attentive and they felt that they had worked at a more concentrated level. This in contradiction to those who did not have plants surrounding them. The test persons that carried out the test surrounded by plants, had a lower blood pressure which again is a clear sign for a decrease in stress.
The presence or non-presence of plants, so the study shows, had no influence on the amount of mistakes made by the test persons. Both groups in rooms with and without plants, made about the same amount of mistakes. Whereby the speed of reaction of the participants that were in rooms with plants, was 12 per cent higher. Due to these results the scientists came to the conclusion that a place of work with integrated plants leads to higher productivity.
Research conducted by Prof. Dr. Tøve Fjeld, Agricultural University of Norway, Ås/Oslo
Reports from the nineteen-eighties indicate that house plants are able to reduce the level of chemical compounds in the air. Both the leaves and the stems and roots participate in this cleansing process, together with micro-organisms which live in t he root zone and the soil. Plants therefore offer an opportunity to improve the often polluted air indoors. They might therefore be able to ameliorate the negative effects on health caused by the atmosphere in public and private spaces.
However, plants do not just act as potential air purifiers. They also represent part of the original ecosystem in which mankind evolved. Plant species as we know them today have been around for some 150 million years. Human evolution only started 4 .5 million years ago, and produced homo sapiens - modern man - about 100,000 years ago. Out entire evolutionary history was therefore closely linked to nature.
It is interesting to note that there have been only very minor changes in mankind's biology, physiology or genetics over the past 10,000 years. We are virtually identical to the people who lived at the end of the ice age, when the ice sheet covered lar ge parts of northern Europe. On the other hand, our living environment has altered considerably, particularly in more recent times.
This started 250 years ago with the industrial revolution, which lead to the urbanisation of the western world. Although this has only occurred over the last 50 to 70 years, mankind appears to have forgotten about its ties to the natural world. This de velopment has cut us off from close contact with nature and has lead to us spending a large proportion of our life surrounded by artificial things.
A modern lifestyle also presents us with a new situation in terms of psychological perspectives on our health. The study of the effect which our environment has on us is called 'environmental psychology'. Studies in this field have clearly shown that o ur environment has a significant effect on our sense of well-being, our emotional stability and our stress limits. They have shown that nature as encountered in parks, open spaces and forests leads to reduced stress. This raises the question: why does nat ure have this effect?
One explanation for this appears to be provided by the concept of "psychological identity". It is not just the physical body that must ensure that we can live and survive in the wilds, but also mankind's psychological component. It is claimed that we s witch on an 'automatic pilot' when we walk - for example - in the woods, that deep within us we have some kind of inherited consciousness which recognises nature and the natural elements as something familiar. On the other hand, when we are in an unfamili ar environment, we use a great deal of mental energy to ensure that a certain distance is maintained.
Our urbanised lifestyle also means - at least in the Scandinavian countries - that we spend 80% to 90% of our time in enclosed buildings. This emphasises the importance of the quality of the indoor atmosphere, both in terms of the physical and chemical state of the air and with respect to psychological effect of the design of the indoor space.
Several studies from the past 10 to 15 years show that the view from the window can affect our sense of well-being. American studies carried out by Roger Ulrich amongst others have demonstrated that the view that a sick person has from their bed can af fect a whole range of measurable stress reactions in patients. Ulrich proved that patients who could see vegetation took far fewer painkillers and were passed as healthy far more rapidly than patients who looked out on a concrete wall. A Swedish study con cluded that office staff who looked out on areas with vegetation suffer less stress than those who look out on an area without plants, such as streets and car parks.
If the view through windows alone can affect not just the way in which mental stress is processed, but even the state of health, plants in the room should have the same effect. At the horticulture and plant institute at the Agricultural University of N orway we even found an additional effect, since plants affect the physical and chemical state of the indoor air. We therefore wanted to test whether it is possible to improve health by means of plants in the office. The study was carried out in conjunctio n with the occupational health service of Statoil, the largest oil company in Norway. A horticultural company - Greenteam - monitored the condition of the plants during the study. We also involved medical colleagues: a specialist in asthma and allergic di sorders and various occupational health experts.
59 Statoil employees took part in the study. They work in office cubicles each covering 10 m2. The study commenced in the autumn of 1994. At the time, there were no plants in any of the offices. The 59 subjects were split into two groups, A and B. Both were well mixed in terms of age and gender, and contained equal numbers of smokers. The average time spent working at the computer was also the same for both groups. During a control period from December 1994 to January 1995 we collected data about 12 di fferent symptoms. These symptoms are largely attributable to the working environment, such as fatigue, headache, dry facial skin and dry skin on the hands, coughing, eye irritation. The data was obtained using questionnaires on which the degree to which t he symptoms were present (on a scale of 0 to 3) could be indicated. The questionnaires were collected every other week.
The results showed no difference between the two groups in terms of the assessment of the state of health. Group A totalled the symptoms at an average of 7.8, and group B at 8.3. The P value is well above 0.05 (5%), so there is therefore no tendency to wards differentiation between the two groups. We concluded from this that the two groups are very similar in terms of their symptoms relating to the indoor atmosphere.
For the actual experiment, all offices in group A (29 persons) were provided with plants in February 1995: three flower boxes containing Oraceana deremensis, Aglaonema commutatum and Epipremnum aureum (Scindapsus aureum) were placed at each window, and a terracotta tub was installed in the corner with a 1.5 metre high Dracaena deremensis and an Epipremnum aureum as the low-level plant.
The same questionnaire was collected every other week during the spring of 1995 (from week 6 to week 17), both from group A (whose members had plants in their office) and from group B (without plants).
The plants were moved to group B in February 1996, with group A serving as the control (so-called crossover). Once again, the questionnaires were collected every fortnight. Judged on all symptoms, a significant improvement can be established when plant s are present in the office. Over the next three months, considerably fewer health problems were reported. According to the findings, symptoms decreased by 25%. If we divide 12 symptoms on the questionnaire into three main categories, the following pictur e emerges:
Group 1 covers general symptoms - fatigue, befuddledness, headache, dizziness and daze together with concentration problems. we found a significant fall in these general symptoms, particularly fatigue and headache, which fell by 30% and 20% respectivel y, when the subjects had plants in their office.
Group 2 covers symptoms of the mucous membranes - itching, burning or irritated eyes, irritated or blocked nose or a runny nose, hoarseness and a dry throat together with coughing. These symptoms were also significantly reduced by plants: hoarseness an d a dry throat by around 30% and coughing by around 40%.
Group 3 cover the head symptoms: dry or irritated facial skin, dandruff, itching scalp and ears and dry, itching skin on the hands. The presence of plants lead to a significant change in the skin symptoms if we look at the results for the face, scamp, ears and hands overall. One symptom that certainly occurred significantly less often was dry facial skin, where the reduction was around 25%.
This study was not conducted in order to examine the causes of the changes in the symptoms. Yet I would like to explore possible explanations. The presence of plants can probably result in a positive change in the psychosocial working environment. The resultant feeling of well-being also affects how the individual assesses his/her state of health. Against the background of the psychobiological identity and mankind's positive reaction to nature we can assume that plants have a particular effect on the s ense of well-being. This is evidenced by the fact that the occurrence of symptoms linked to the indoor atmosphere was reduced.
The individual experience of the subject's state of health can be at least partly explained by the following reasoning: an improved sense of well-being raises the levels of tolerance for irritation. Consequently, the individual will experience the indo or atmosphere more favourably if there are plants in the working environment.
On the other hand, we can also assume that plants can have a direct effect on the atmosphere; according to American research findings, houseplants break down a variety of chemical compounds in the air. They may also slightly raise the ambient humidity, as English studies suggest. These two factors can lead to an improvement in the indoor atmosphere, which in turn leads to fewer health problems. My personal opinion is in any case that the psychosocial effect (i.e. increased sense of well-being) has a si gnificantly greater significance for our findings as a direct consequence of the air quality.
In addition to the information, we wanted feedback on how the subjects experienced the presence of plants in their workplace. To that end, we sent a new questionnaire to all participants a month after the completion of the health stage, in which we ask ed for their views regarding the plants.
56% of participants felt that the plants took up a lot of room. The positioning of the plants in the office should therefore be done in such a way that the workplace is not noticeably restricted, for example by hanging the plants in the window or on th e wall. Only 11% felt that plants had caused problems in the workplace.
A proportionately large number of subjects felt that the air in the office had been improved when it contained plants (22% agreed with this fully, and 24% partly). The majority said that they felt more comfortable with plants (84% agreed fully or partl y). Amongst 51 subjects who participated in the experiment to the end, there was a substantial desire to have plants in the office in future. 66% were fully in favour of this, and 16% partly in favour, making a total of 82%. Only one person fully opposed it.
We can therefore draw the following conclusions. Plants in offices can improve the sense of well-being and health. Health problems affected by the indoor atmosphere occur less frequently, and the employees feel the plants to be a positive element. It i s consequently obvious to assume that plants can help reduce the costs resulting from short-term absence due to illness. Effectiveness at work can be improved both through the reduction in health problems and an increased sense of well-being. This is inte resting from a economic perspective, not least because the individual planting can easily be adapted to the workplace in question. Finally, it should not be forgotten that the individual employee's sense of well-being is clearly promoted, and that plants in the workplace can therefore also help improve quality of life overall.
These were a few of the findings of the Norwegian study. As far as we know, this is the first study in the world to directly link the use of plants to health. With medical questions, two independent studies with similar findings are always required in order to be able to make definite statements. We therefore dare to draw the conclusion that plants in offices have a positive effect on individuals' health and sense of well-being. And we hope that our study can prompt further research in this field.
obtained her doctorate at the Norwegian Agricultural University in Ås/Oslo in 1989. She has since worked at the Norwegian Institute for Horticulture and Botany and had been leading a study into the possible effect of plants on the health of offic e staff since 1994. Mrs Fjeld is also a lecturer at the Agricultural University and a member of the Scandinavian Society for Agricultural Research and the International Society of Horticultural Sciences.
The influence of plants on air quality for the general well-being of people has been proven. Even more important is, however, their positive psychological effect on our perception and thinking.
Plants in offices are beneficial to people. They create an individual working environment and bring colour into the room. They hereby give a feeling of well-being and create a live atmosphere. They are beneficial for a positive mood and help to overcome stress. In this way, ficus, banana and co help to improve the room climate. Fact: In offices with plants, complaints about headaches, nervousness, heart/circulation-symptoms as well as colds are more seldom. In the following we would like to present to you why this is so, and how you can make use of the advantages of an office with integrated plants.
Plants regulate the climate. They influence the humidity and improve the air quality in that they take in carbondioxide and give off oxygen and they bind dust and harmful substances.
The air temperature should rather be low than too high and should have the same value at head and foot level: Normally 21°C to 22°C and with high outside temperatures maximally 26°C. The relative humidity should not drop below 30 %. This is often unavoidable during winter months because the air humidity drops without extra humidifying. This low air humidity results in the drying out of the mucous membranes of the upper respiratory tracts and can, in the long run, lead to chronically inflamed mucous membranes. Drying out of the skin and irritation of the eyes are the consequence. A dry nose/throat does not only negatively affect general well-being but also results in a bad defence shield against bacteria and viruses. The result: Cold-germs can easily settle in.
Using green plants with a high need for water, for example nest fern, banana, African hemp and also Cyperus alternifolius, the humidity can be increased in a natural way. The air humidity should not rise above 60 per cent to 65 per cent because under certain circumstances, this could cause mould.
Important: The room air must be free of all pungent smells and odours and toxic substances. Because parallel to the unappetising odours, the carbondioxide content also rises, as a rule. The margin of tolerable odour concentration is exceeded at 0.1 per cent vol. The more carbondioxide in the air, the more tired and listless we become. The more leaf surface a plant has, the more effectively it can discharge carbondioxide. Here, it is not the size of the single leaf, but the whole leaf surface of the plant that matters. Banana, ficus species and green-leafed wine have a large leaf surface. Dry air is always more dusty than humid air. Dust particles are always lighter when they do not hold much moisture. Furthermore, by means of electrostatic charge, the dust particles are suspended in the air.
On their own, plants are not suitable as biological air filter systems for means of reducing harmful substances indoors. In the case of reduced air quality due to harmful substances in the office, for example smoking, solvents and wood impregnation, the recognition and elimination of the source is of top priority. Airing the room at regular intervals is also of extreme importance.
An additional biological air filtering by plants was experimentally proven in two ways:
a) The ribs of the leaves of the plants take up the harmful substances, collect, process and filter them. For example, this has been scientifically proven for formaldehyde.
b) The harmful substances in the air get into the soil, i.e. a hydroponics substrate with a high content of activated carbon. The next step is that either the harmful air substances are directly absorbed by the roots of the plant and are then transported to and processed, respectively deposited, by the plant or the processing by soil bacteria, for which the harmful substances serve as a source of nourishment. Due to the normally low quantities of harmful substances indoors, it is necessary to additionally feed the bacteria which process harmful substances. Long term tests have shown that immunised bacteria survive for months even without the continual supply of formaldehyde or nicotine and become immediately "active" as soon as they receive harmful substances. However, the processing rates of plants only work out to approximately 1 per cent of the processing rate of bacteria. As the detoxifying potential of plants is relatively low, rooms must be richly decorated with plants in order to make use of this effect. Normally, the concentration of harmful substances in offices does not constitute a health hazard.
In order for indoor plants to carry out their meaningful function as a significant element of well-being, not only the right plants and design are important, but, as a matter of fact, also the right care. In practice (good lighting conditions, fertilisation of the plants without pests, no flooded roots in hydroponics tubs) this can easily cause problems.
Summary: The influence of plants on air quality for the general well-being of people has been proven. Even more important is, however, their positive psychological effect on our perception and thinking.
Author: Dr. Leona Rogler; for: 'The comprehensive office series' of the Association for Administrative Professions
Research conducted by Prof. Tøve Fjeld, Department of Horticulture and Crop Sciences, Agriculture University of Norway
Prof. Tøve Fjeld, Department of Horticulture and Crop Sciences, Agriculture University of Norway Plants do not only serve as a means for processing air, they are also part of the original ecological system from which man evolved. In human biology, physiology and geno-type have changed very little in the last 10,000 years, whereby changes in human environment are fundamental. When looking at the last 50 to 70 years one notices that in the western world a far reaching urbanisation has taken place. At present, millions of people live with little or no contact to nature - without woods or open country-side, lakes, parks or gardens.
Above this, our present life-style - at least in Scandinavia - results in the fact that 80 to 90 per cent of the time is spent indoors. The specialist field covering the influence of the environment on human psyches is called environmental psychology. Environmental psychological studies have shown obvious links between well-being, psychological stability, stress level, other important aspects of human life and environmental factors. All these studies indicate that nature - such as plants, lakes and woods - can offer an important contribution to the reduction of stress. An urban environment, however, causes psychological stress.
The hypothesis on which this study is based, is that an integration of plants into our direct environment - inside buildings - has a direct influence on how people evaluate their well-being and state of health. In our opinion it is possible to collect data as to how a person evaluates his or her state of health and then to connect this data with the presence of indoor plants.
The study on the influence of indoor plants on the state of health of office employees was carried out in the course of a co-operation between the Department of Horticulture and Crop Sciences and the head-office of Statoil Norge A/S. 62 people took part in the study. The offices were standardised as to the size (10 m²) and the window area. By means of a standardised questionnaire we collected data reference how the test persons evaluated the room climate and how, in their opinion, this had an effect on 12 different illness-symptoms.
These symptoms are, according to earlier studies, indicators for problems in the area of room climate. During a control period of four months in autumn 1994, background information was collected every two weeks, in order to achieve a "control-level" of the test persons. 29 offices were equipped with standardised indoor plants ("plants-group"), while the other 32 offices formed the control-group. The plants were introduced into the offices in February 1995. During the months of February, March and April the test persons filled in the standardised questionnaires every two weeks.
The preliminary results after the first year of the study indicate that plants do indeed have an effect on the subjective evaluation of the state of health. The results can be compiled as follows:
The question is, however, whether or not the results from this study will still be valid over a longer period of time. In order to achieve permissible results, it is necessary to prolong the study. We also need information about how and in which way the effects will change during the different seasons. If these effects can still be proven after a further year, then plants are a very important factor reference the reduction of complaints in connection with room climate. Plants could, in this way, be an important means of cost reduction in the area of short term sickness due to minor ailments and would be a contribution to the effectiveness of a company. A further - and possibly more important - point is that this would increase the well-being of the employee and hereby the quality of his/her work routine.
Research conducted by Prof. Dr. Konrad Botzenhard, Hygiene-Institute of the Tübingen University
Prof. Dr. Konrad Botzenhard, Hygiene-Institute of the Tübingen University
People must breath to extract oxygen from the air and exhale the carbondioxide produced in the body. For this gas-exchange, the human lung has an available capacity of approximately 80 m². During breathing the air in the lung-alveolus is only exchanged with fresh air to the extent of approximately 15 to 30 per cent, so that gas concentration during breathing only differs slightly here. The oxygen partial pressure in the alveolus air lies by 98 torr as opposed to 150 torr in the inhaled air.
The oxygen content in the arterial blood changes so little, up to 80 torr partial pressure in the alveolus air, that minor deviations in the oxygen content of the indoor air have only little effect on breathing. It is almost the same with the carbondioxide concentration. In the alveolus this lies at approximately 40 torr or approximately 5 per cent vol. so distinctly above the concentration of the outside air of approximately 0.03 per cent vol., minimal deviations in the outside air have no meaning in respect to breathing.
The Pettenkofer-Value of 0.1 per cent vol. seen as the margin of acceptable CO²-concentration is only of significance as an indicator for the pollution of the indoor air regarding human evaporates, but has no significance to breathing functions. During breathing, humidifying and warming of the air takes place in the upper respiratory tracts , where only a much smaller area is available. Especially in winter, the drying out of the mucous membranes is often complained about.
Due to this, it seems sensible to guarantee a minimal air humidity of 30 to 40 per cent indoors. Furthermore, particular harmful substances in the respiratory tracts should be held back and transported out, without them reaching the alveolus and hereby passing into the body. For this purpose, the bronchial pulmonary system including the mucous membrane of the nose has ciliary epithelia and gland cells for the production of mucous.
The overproduction in this system often leads to colds, it is therefore an important quality criteria that the air is free from dust. This especially applies to biological active dust, for example micro-organisms and allergens. The dust content of the air is dependent on the relative humidity. Chemical irritations of the respiratory tract as well as odours can have an effect on the innervation of the respiratory tracts through the autonomous nerve system. Generally this is indicated in a constriction of the respiratory tract and even involuntary holding of breath and an increased blockage of the respiratory tract.
The evaluation of the quality of odour of indoor air is the basis for the so-called Olf-Concept, which has since found its way into standardisation. It seems possible that through the increased use of plants indoors factors such as relative humidity, particle content and odour quality can be positively influenced.
Houseplants have more to offer than mere aesthetic appeal - in a world where we spend more and more time indoors, they provide us with a much needed reminder of the kind of environment we evolved in.
Houseplants have more to offer than mere aesthetic appeal - in a world where we spend more and more time indoors, they provide us with a much needed reminder of the kind of environment we evolved in. Research into the beneficial attributes of plants was first conducted by NASA in the 1970s. NASA scientists discovered that houseplants were able to purify polluted air and water. Since then many countries and authorities have developed their own research programmes.
In Germany a research programme, funded by the Bavarian state, was started in January 1998 by Dr Peter Reimherr of the Bavarian State Institute of Horticulture and Viticulture. The programme is scheduled to run until 31st December 1999 and is attempting to find the effect plants have on people who spend a lot of time indoors. The research focuses on general wellbeing, health and also efficiency of the workforce.
Questionnaires have been distributed to 140 people in 105 offices. Participants are asked to complete them at regular intervals. This includes a before and after comparison to find out how office workers perceive the difference achieved by plants, focusing on perceptions of space, wellbeing and health. Effects on humidity, temperature and light are also measured. All staff involved have reacted very positively to the changes and are very interested in the project.
Researchers are now also looking into the reasons why plants have all these positive effects on people. One theory is that during the last 2 million years people have evolved in open spaces, settling around clusters of vegetation. Therefore on a subconscious level plants may still signify water, food and protection and therefore, increased chances of survival.
Such diverse groups as architects, psychologists, gardeners and doctors alike eagerly await the results of Dr Reimherr's research.
The condition of indoor air has been a concern since the early eighties when Sick Building Syndrome was recognised. Where schools suffer from this condition, the introduction of a few plants into classrooms, staff rooms and offices is a simple and cost effective way to improve how everyone actually feels.
The condition of indoor air has been a concern since the early eighties when Sick Building Syndrome was recognised. Where schools suffer from this condition, the introduction of a few plants into classrooms, staff rooms and offices is a simple and cost effective way to improve how everyone actually feels. With constant pressures on funding, education and local government officials will be pleased to learn that using plants is a cost effective way to purify the air so making staff and pupils feel and perform better. An added bonus is that the aesthetic value of the plants will also improve the morale of staff and pupils.
In research carried out at a Norwegian primary school, plants were introduced into classrooms to improve the indoor atmosphere. Findings from the research show that there were less health problems in the classrooms where the plants were located. Pupils also reported a positive appreciation for the plants, reporting that their classrooms felt fresher, generally more pleasant and attractive. These results confirm earlier findings from similar research carried out in an office environment.
Both surveys were conducted by Professor Tove Fjeld of the Horticultural Institute at the Norwegian College of Agriculture. The school in question in Tønsberg, Norway, had a record of serious health problems due to the indoor climate in classrooms and other areas of the school. Ventilation was poor and a lack of funds, a problem not unfamiliar to the UK, meant there was no possibility of investing in better ventilation or structural improvements. This project was chosen as an alternative method to improve conditions. It involved the use of plants in a biological system.
Fjeld used four metre-long containers, planted with a selection of plants and positioned in selected classrooms. The containers known as Bioprocess® units had a reservoir with both compost and water, acted as complete biological systems. The surrounding air is drawn into the system by means of a pipe and distributed throughout the compost.The noiseless Bioprocess® system not only helps clean the air of impurities but also improves the evaporation of water, ensuring that the biological system makes a major contribution to purifying the air.
It is well established from earlier work carried out by several researchers, that the roots of plants break down any chemicals which have been absorbed in this way or naturally through the plant's leaves, turning them into food for the plant. Similarly, in the natural process of transpiration, plants help to control the humidity of the air.
Between February 1997 and February 1998 the research was carried out with two test groups. One group, involving 61 pupils and 8 teachers, had the planted units, whilst the other group remained in the original conditions with no planted units and was made up of 59 pupils and 2 teachers.Teachers and pupils answered 4 questionnaires before, during and at the end of the experiment, to ascertain how they felt. The findings from those who had worked in the classrooms with plants, found that symptoms were considerably reduced.
For an added bonus, plants have also been found to aid concentration and productivity. Research carried out in America showed that plants improved concentration levels. Washington professor, Virginia Lohr took two similar groups working in windowless computer labs, one group with plants and one without. Both groups used a specially designed computer programme so that they both undertook similar work. Their emotional states, pre- and post-task blood pressures and pulse rates were measured before, during and after the experiment.
Whilst both groups made a similar number of mistakes, the group which worked with plants present, recorded a reaction time which was 12% quicker than those working without. In effect, this meant their production rate was greater too.
The blood pressure and pulse rates of the part icipants also returned to normal more quickly and their scores showed significant increases in post-task attentiveness. Professor Fjeld is continuing her research with groups in two further schools. Meanwhile, hard-up local authorities could do worse than install a few plants in their classrooms to make them not only more pleasant places to be but also healthier places in which to learn and work.
Plants have played a decorative role in rooms for over 100 years. By comparison, a much younger consideration is that, apart from their aesthetic enrichment, plants could also have further uses. Only since the last 25 years, have individual studies shown which room-climatic, room-acoustic and psychic effects plants can have in buildings.
Considerable academic research, which shows that plants can improve health in the workplace, has been carried out. The research has shown that plants reduce complaints of minor ailments, generally improve the feeling of well-being and also reduce stress levels.
During a two year study in Bavaria, Engelbert Kötter working on behalf of the Bavarian State Ministry of Nourishment, Agriculture and Forestry, found that plants in offices improved employee's perception of their well-being as well as improving the comfort-factor of the offices.Taking 94 offices and 139 office employee's, Kötter introduced plants into the offices and measured humidity and light levels which are important for plants and people; he also assessed the workers' perceptions of change to the climate of the rooms and to their own well-being by means of a series of questionnaires.
Kötter also addressed the issues of noise reduction by plants and dispelled fears that plants introduced dust and germs to the environment.* Central heating or air conditioning can dry the air, which can cause respiratory and skin irritation. The optimum humidity level for comfort is about 60%. Kötter's findings showed that common houseplants such as Spathiphyllum (Peace Lily), African violet, Epipremum (Devil's Ivy) and Ficus pumila raised the humidity levels by 2 - 5% making the office atmosphere more comfortable for inhabitants. Office employee's also recorded that the environment offices with plants felt fresher, made them feel less stressed, made the working feel more human and in general seem to up-grade their environment.With improved conditions and perceptions, office employee's will enjoy their work situation better; happy employees = more output and happy bosses.
In America, Prof Virginia Lohr found that plants had beneficial effects. For her study of two groups of computer operators, she monitored their pulse rates, their blood pressure and skin conductivity, whereby increases in these measurements show the physiological signs of increased stress. Her findings showed that the pulse rates, blood pressure and skin conductivity of the operators working in the computer lab with integrated plants, all returned to normal more quickly. Not only that, but their concentration was better enabling them to make corrections more quickly and proving them to be 12% more productive.One would imagine that anything that reduces stress would be of interest to employers.
The Confederation of British Industry last year published figures that showed that 1 in 5 of us will take time off work because of stress. In 1999 this meant that the British Industry lost 6.7 million working days due to stress or stress related illnesses. The cost of this was around £7 billion last year to British Industry (Health & Safety Executive).
In Norway, Prof Tøve Fjeld of the Agricultural University in Oslo has carried out several studies reference the discomfort of workers. Her findings have been consistent: plants reduce minor ailments often linked to Sick Building Syndrome.Her first study was at the Statoil Offices in Oslo, where in a 2-year study using questionnaires with 2 groups of workers, she found that complaints of minor ailments decreased once plants were introduced into the offices.
| Ailment | % reduction |
| Fatigue | 20 |
| Headache | 30 |
| Sore/dry throats | 30 |
| Coughs | 40 |
| Dry facial skin | 25 |
| Well-being | +84 |
She has had similar results in three further projects, two in schools and the third in the X-ray department of the Radiological Hospital in Oslo.In the x-ray project, not only were complaints of ailments reduced, but the mid-afternoon tiredness, common in many workplaces, ceased. On average, absence from work dropped from 15.85% to 5.55%. Last but not least, the smell of the chemicals used in the process of x-raying was reduced once the plants were introduced. All in all the plants made the x-ray department a healthier place for those working there.
Research results are positive - plants do improve health in workplaces. For employers, investment in interior landscaping to make workplaces healthier places is a small outlay for the savings in costs, which result from reduced absence from work, and improvements in productivity.
The link 'plant' has gained importance in architecture as a media against over-technicalisation and the alienation to nature. People react positively towards indoor plants. Above this, plants take on important functions of well being such as acclimatisation, the binding of dust and harmful substances and the reduction of noise.
The link 'plant' has gained importance in architecture as a media against over-technicalisation and the alienation to nature. People react positively towards indoor plants. Above this, plants take on important functions of well being such as acclimatisation, the binding of dust and harmful substances and the reduction of noise. At the same time they support stress reduction. People are drawn to plants and have a close relationship to them, especially in the concrete desserts known as towns. Life has been revolutionarily changed through the cultivation of plants by humans of the early epoch. The vital comprehension of the interplay of man and plants though, has been lost due to industrialisation.
Indoor plants also influence the perception of the persons working and living in the related building. Hereby, smells play an important role. Because though, people react differently to smells, strongly smelling plants should only be used sparingly.
As the sun is the only unproblematic source of energy that we have and as it is unrenounceable for our lives, a co-operation between sun and plants should form a new kind of architecture. During the planning of a building, the guidelines of solar architecture must be taken into consideration. Which climatic zones does it have, how much light is available and how is the building constituted. To carry out the conversion in the best possible way, interdisciplinary co-operation must take place. For example, during one project, a heating and ventilation engineer, a garden layout specialist and an electric-planner are involved.
Australian environmental researcher finds more proof that indoor plants reduce health risks.
Australian environmental researcher finds more proof that indoor plants reduce health risks.
SYDNEY - In an ongoing environmental research project, University of Technology - Sydney Research Associate Ron Wood has discovered even more beneficial facts about how plants clean indoor air. Wood and a team of scientists, including a plant physiologist / ecotoxicologist, biochemist / analytic chemist , microbiologist and environmental / urban horticulturist , conducted experiments based on Dr. Wolverton's NASA Research, but took the experiments a step further.
The project, funded by the Flower Council of Holland and the Australian Horticultural Research Development Corporation, placed three species of plants, Howea forsteriana (Kentia palm), Spathiphyllum var. Petite (Peace Lily0 and Dracaena deremensis var. Janet Craig, in sealed chambers and subjected them to two common indoor toxins, n-hexene and benzene, a known carcinogen.
The experiments repeated Dr. Wolverton's results showing that the plants removed the toxins from the chambers. According to Wood, the removal rate was slow at first, but increased substantially after a few days. He attributes this to biochemical systems that switch onto deal with the toxins - it absorbs and metabolizes them. When the level of toxins was increased, the plants maintained or increased their removal rates.
The project also included an experiment that placed the plants in total darkness - when photosynthesis does not take place and the stomata's are shut, preventing gaseous absorption into the leaves. No reduction in the removal rate occurred. Instead, in some cases, the removal rate increased and improved that light is not necessary for the removal process.
Next the research team added more toxin to the chambers to try achieve saturation or the point where the plants could no longer remove toxins. In the 7 to 10 day timeframe in which the experiments were conducted, the team could not achieve saturation of the plants. This observation led Wood's team to an additional test - on the potting medium. What role do the microorganisms play in the removal process?
For this part of the research, the plants were removed from the chambers and the potting mix was returned with new doses of toxins added. The result: The removal rates remained high, only slightly less than those obtained with the plants present. Even after 7 to 10 days without the plant, the removal rate was maintained.
According to Wood, this means that removal is a biological process and the microorganisms in the potting soil are the rapid-removing agents of the removal system.
To further his findings, Wood decided to test the plant itself. First the roots were washed in sterile water to remove any remaining potting mix and as many microorganisms as possible. The plant was placed in the chamber in a hydroponics solution (no potting mix), under the same conditions as before. Again removal activity took place. In some tests, the removal activity was the same as when the plant was in the potting mix, suggesting that microorganisms must still be present in the root system The difference in the removal rates among the plants suggest that different relationships exists between the plants and their root-associated microorganisms.
The final test was on "virgin" potting mix that has never been associated with a plant. In this test removal was still achieved, but at a much slower rate and at a level lower than with plants, and was exhausted after 9 to 10 days. Wood asserts that these results show microorganisms exists independently in the potting mix, but are unable to grow and reproduce in the absence of a plant, so toxin removal using only potting mix is short-term.
"Our research provides new information about the induction effect, or the "switching on" of a biochemical system to absorb and metabolize a chemical compound," Wood says. " This is new information showing that longer plants are exposed to toxins, the better the plant/soil system works at removing them. This is the first time that this has been demonstrated.'
Wood's team feels these findings reinforce Wolverton's research and provide ample documentation for promoting indoor plants as necessary clean air tools.
According to Wood, who is INTERIORSCAPE magazine's Clean Air Correspondent, the findings are accepted by the International Society for Indoor Air Quality and Climate, the World Health Organization and the United States Environmental Protection Agency (EPA).
In a related study, the EPA recently published its draft of the "Healthy Buildings, Healthy People" report, outlining the problems associated with indoor air toxins (sick-building syndrome) and the need for aggressive programs to address indoor air pollution problems.
In a letter to INTERIORSCAPE.com's 'Scaper Talk, Wood points out, "In the EPA's final draft, among the five goals for upgrading indoor environments is: No. 4 - Create and use innovative products, materials and technologies. I think the EPA's goals present the possibility that living plants indoors enhance people's health and environment. This is more than selling pork against beef. This report should be required reading for all interiorscapers, and the uppermost in the minds of those directing the Growth Initiative."
Research conducted by Oxford Brooks University. Source: Interiorscape magazine - 24 August 1999.
Research conducted by Oxford Brookes University
Interior planting has become increasingly popular in the working environment during the last 30 years, and its presence is believed to have psychological and physiological benefits. There are many claims in the literature that have not been substantiated by research. My thesis, titled Human Responses to Interior Planting, set out to establish why people need or want to have interior planting in their present-day buildings and to determine the possible psychological benefits to people of plants inside buildings.
Two separate studies were carried out:
The first study was a longitudinal case study in a hospital atrium using questionnaires and observations. This study tested the impact of interior planting on:
The second study was a laboratory study to test the impact of interior planting on recovery from attentional fatigue and used vigilance tests, including a proof reading.
The presence of interior planting plays a role in human psychological well-being because:
The absence of interior planting in a building elicits a more negative human psychological response because:
Two studies were conducted by M.Sc. environmental psychology students from Surrey University during the spring and early summer of 1997. The experiments were designed to examine the effects of plants on people in a simulated working environment. Study 1: The Effect of Interior Planting on Stress by Helen Russell
The first study attempted to test whether the presence of plants in a room affected the stress levels of people undertaking a complex test. Participants in the study were invited to an office that had no plants or was heavily planted. Sensors were attached to the skin of the participants to record skin conductivity, heart rate and blood pressure. The participant was allowed to get used to the surroundings for 10 minutes, during which time a base line recording of his stress levels was recorded. After this 10 minute period, the participant was asked to add up a list of 78 numbers without using his fingers or counting aloud. During the time they were allowed for the test, additional distractors, such as the sound of a ringing telephone or traffic noise, were played to them at random intervals. After the test, a further 10-minute period of rest was allowed.
This study was an attempt to find objective measurements of what was already widely perceived, namely that plants in offices can reduce stress. Of the tree types of measurements made, skin conductivity showed the greatest difference between the group exposed to plants and the group in the unplanted office. The results showed that, for this measurement, stress was reduced in the planted office. The other tests showed very little difference between the two situations. The results also showed that those people in the planted office recovered from their stress more quickly than those in the unplanted office during the 10-minute post-test rest period.
The reasons for the difference between the groups were also discussed. It is thought that the presence of plants made the office more interesting. A comparison with other decorative objects in an office would have to be made to see whether there was something inherently special in plants that has an effect on perception.
The effect of plants on stress may well be small and not apparent in those situations where the task performed is especially complex. In these situations, a person will be concentrating so much on the task in hand, that the surroundings make little impact. However, in situations where the task being performed is less complex or boring, the soothing effects of plants may be more noticeable and have a greater effect on the people doing the task. This could be the subject of further study and may have implications on workplace productivity.
Study 2: Human Responses to Office Interior Planting by Matthew Hampshire
This study examined the levels of plants needed in an office to evoke a response. The experiments tested a hypothesis that said as interior planting presence increases, so will the positive perception of that space up to an optimum level. An office was furnished and plants were positioned in the office at six different densities, ranging form zero to very heavily planted. The room was photographed at the different densities so that each incremental increase in plant density was approximately 6 percent greater than the previous in terms of the area of the photograph containing plants. The photographs were shown to a group of individuals, who were asked several questions about the pictures they saw.
First, participants were shown a picture for 30 seconds, after which they were asked to recall the objects other than plants in the picture. The results of this experiment suggest that planting density had no significant bearing on short-term recall.
The second test was an examination of the perception of the office at the various planting levels. Participants were asked to judge the office using bipolar adjectives. This means that participants were asked to score the room on a scale of one to seven for each pair of opposite adjectives, such as friendly and unfriendly or complex and simple. Eighteen such pairs of adjectives were chosen for the test. The results showed that, generally, the positive perception of the office increased as plants were introduced.
The final test asked participants to rank the photographs in order of preference. The clear result from this experiment showed an aversion to the unplanted room, whereas the preference for the other planting levels was less obvious. Very dense planting levels were disliked, as it was thought that such high levels of planting might make the office impractical to use. The results suggest that the arrangement of the plants in the office may have a dramatic effect on perception independent of the quantity of plants. The introduction of a dominant trough into the scene had a disproportionate effect on perception for the increase in plant density it caused.
This study demonstrated a positive perception toward plants in an office, although it is hard to extract the reasons for such perceptions. Further work on this is required to find out what it is about plants in offices people like and whether good design of plant displays is as important as the number of plant in an office.
Definition: an acute incidence of indoor air pollution that can occur in closed or poorly ventilated offices and residences.
Numerous studies conducted by the EPA (Environmental Protection Agency) over the last 25 years have shown measurable levels of over 107 known carcinogens in modern offices and homes. The presence of these VOC's (volitile organic compounds) is due to the switch from open windows to energy efficient living and working environments, made necessary in the 1970's due to the energy crisis atmosphere that had developed. Combined with the advent of modern building methodology and products, the result has been energy efficient homes and offices that contain amounts of known cancer causing chemicals. In extreme cases, some buildings have such high levels of contaminants that they are known as "Sick Buildings" because exposure to them results in multiple symptoms of sickness exhibited by the inhabitants who try to use them.
The fact that concerns most scientist and doctors is the unknown effects that could occur in humans over long periods of time, being in contact with low dosages of these cancer causing VOC's such as are found in modern offices and homes. Scientists say it is still too soon to tell whether increased incidences of cancer can be attributed to exposure to modern living and working stations.The NASA research suggest that by including indoor house and office plants, one may reduce substantally the amount of exposure to now common VOC's one experiences daily routine. On going research indicates that lessening prolonged exposure to VOC's and other commonly found indoor polutants (secondhand smoke, ozone, etc.) can substantilly to your long term quality of life.
In summary, the NASA research combined with increasing large amount of corroborating research indicates that it is beneficial to have live plants in modern office and home environments. Plants and the accompanying benefits they bring, can help to improve indoor air quality in any building. Combined with increased ventalation rates and other recommended remedies, plants even help clean up 'Sick Buildings"
NASA Study shows common plants help reduce indoor air pollution
Common indoor plants may provide a valuable weapon in the fight against rising levels of indoor air pollution. Those plants in your office or home are not only decorative, but NASA scientists are finding them to be surprisingly useful in absorbing potentially harmful gases and cleaning the air inside modern buildings.NASA and the Associated Landscape Contractors of America (ALCA) have announced the findings of a 2-year study that suggest a sophisticated pollution-absorbing device: the common indoor plant may provide a natural way of helping combat "SICK BUILDING SYNDROME".
Research into the use of biological processes as a means of solving environmental problems, both on Earth and in space habitats, has been carried out for many years by Dr. Bill Wolverton, formerly a senior research scientist at NASA's John C. Stennis Space Center, Bay St. Louis, Miss.Based on preliminary evaluations of the use of common indoor plants for indoor air purification and revitalization, ALCA joined NASA to fund a study using about a dozen popular varieties of ornamental plants to determine their effectiveness in removing several key pollutants associated with indoor air pollution.
NASA research on indoor plants has found that living plants are so efficient at absorbing contaminants in the air that some will be launched into space as part of the biological life support system aboard future orbiting space stations.While more research is needed, Wolverton says the study has shown that common indoor landscaping plants can remove certain pollutants from the indoor environment. "We feel that future results will provide an even stronger argument that common indoor landscaping plants can be a very effective part of a system used to provide pollution free homes and work places, " he concludes.
Each plant type was placed in sealed, Plexiglas chambers in which chemicals were injected. Philodendron, spider plant and the golden pothos were labeled the most effective in removing formaldehyde molecules. Flowering plants such as gerbera daisy and chrysanthemums were rated superior in removing benzene from the chamber atmosphere. Other good performers are Dracaena Massangeana, Spathiphyllum, and Golden Pothos. "Plants take substances out of the air through the tiny openings in their leaves," Wolverton said. "But research in our laboratories has determined that plant leaves, roots and soil bacteria are all important in removing trace levels of toxic vapors"."Combining nature with technology can increase the effectiveness of plants in removing air pollutants," he said. "A living air cleaner is created by combining activated carbon and a fan with a potted plant. The roots of the plant grow right in the carbon and slowly degrade the chemicals absorbed there," Wolverton explains.
NASA research has consistently shown that living, green and flowering plants can remove several toxic chemicals from the air in building interiors. You can use plants in your home or office to improve the quality of the air to make it a more pleasant place to live and work - where people feel better, perform better, any enjoy life more.
| Common Name | Scientific Name |
| Bamboo Palm | Chamaedorea Seifritzii |
| Chinese Evergreen | Aglaonema Modestum |
| English Ivy | Hedera Helix |
| Gerbera Daisy | Gerbera Jamesonii |
| Janet Craig | Dracaena "Janet Craig" |
| Marginata | Dracaena Marginata |
| Mass cane/Corn Plant | Dracaena Massangeana |
| Mother-in-Law's Tongue | Sansevieria Laurentii |
| Pot Mum | Chrysantheium morifolium |
| Peace Lily | Spathiphyllum "Mauna Loa" |
| Warneckii | Dracaena "Warneckii" |
Chemicals UsedTrichloroethylene (TCE) is a commercial product found in a wide variety of industrial uses. Over 90 percent of the TCE produced is used in the metal degreasing and dry cleaning industries. In addition, it is used in printing inks, paints, lacquers, varnishes, and adhesives. In 1975 the National Cancer Institute reported that an unusually high incidence of hepatocellular carcinomas was observed in mice given TCE by gastric intubation and now considers this chemical a potent liver carcinogen.Benzene is a very commonly used solvent and is also present in many common items including gasoline, inks, oils, paints, plastics, and rubber. In addition it is used in the manufacture of detergents, explosives, pharmaceuticals, and dyes.
Benzene has long been known to irritate the skin and eyes. In addition, it has been shown to be mutagenic to bacterial cell culture and has shown embryotoxic activity and carcinogenicity in some tests. Evidence also exists that benzene may be a contributing factor in chromosomal aberrations and leukemia in humans. Repeated skin contact with benzene will cause drying, inflammation, blistering and dermatitis. Acute inhalation of high levels of benzene has been reported to cause dizziness, weakness, euphoria, headache, nausea, blurred vision, respiratory diseases, tremors, irregular heartbeat, liver and kidney damage, paralysis and unconsciousness. In anima tests inhalation of benzene led to cataract formation and diseases of the blood and lymphatic systems. Chronic exposure to even relatively low levels causes headaches, loss of appetite, drowsiness, nervousness, psychological disturbances and diseases of the blood system, including anemia and bone marrow diseases.
Formaldehyde is a ubiquitous chemical found in virtually all indoor environments. The major sources which have been reported and publicized include urea-formaldehyde foam insulation (UFFI) and particle board or pressed wood products used in manufacturing of the office furniture bought today. It is used in consumer paper products which have been treated with UF resins, including grocery bags, waxed papers, facial tissues and paper towels. Many common household cleaning agents contain formaldehyde. UF resins are used as stiffeners, wrinkle resisters, water repellents, fire retardants and adhesive binders in floor coverings, carpet backings and permanent-press clothes. Other sources of formaldehyde include heating and cooking fuels like natural gas, kerosene, and cigarette smoke.
Formaldehyde irritates the mucous membranes of the eyes, nose and throat. It is also a highly reactive chemical which combines with protein and can cause allergic contact dermatitis. The most widely reported symptoms from exposure to high levels of this chemical include irritation of the eyes and headaches. Until recently, the most serious of the diseases attributed to formaldehyde exposure was asthma. However, the Environmental Protection Agency (EPA) has recently conducted research which has caused formaldehyde to be strongly suspected of causing a rare type of throat cancer in long-term occupants of mobile homes.