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The Effects of The Number of Indoor Foliage Plants on Productivity, Stress and Attention

  • June 2013
  • Conference: CLIMA 2013 International Conference on IAQVEC
  • At: Prague, Czech Republic
  • Volume: 8th
Authors:
Desto Jumeno at Universitas Andalas
Desto Jumeno
Hiroshi Matsumoto at Toyohashi University of Technology
Hiroshi Matsumoto
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Abstract and Figures

The number of researches on the effect of indoor plants to improve the quality of the workplace has increased. However, the results were varied. These differences in results might be caused by differences in the method adopted by each researcher, such as differences in the task, in acclimatization time, in work duration, in the number of plants, the size of plants and also the arrangement of plants. The objective of the present study is to investigate the effects of the number of plants on human productivity, stress and attention. In the present study, subjects were instructed to conduct a word searching task in a room with different numbers of plants on each condition. The results showed that there was no significant difference in productivity, stress and attention among four conditions. Significant differences were found in the subject's perception of friendliness, comfort, freshness, and cleanliness of the workplace.
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CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
The Effects of The Number of Indoor Foliage Plants on
Productivity, Stress and Attention
Desto Jumeno1,2, Hiroshi Matsumoto3
1,3 Department of Architecture and Civil Engineering, Toyohashi University of
Technology, Japan
2 Department of Industrial Engineering, Andalas University, Indonesia
d119405@edu.tut.ac.jp
Abstract
The number of researches on the effect of indoor plants to improve the quality of the
workplace has increased. However, the results were varied. These differences in
results might be caused by differences in the method adopted by each researcher,
such as differences in the task, in acclimatization time, in work duration, in the
number of plants, the size of plants and also the arrangement of plants. The
objective of the present study is to investigate the effects of the number of plants on
human productivity, stress and attention. In the present study, subjects were
instructed to conduct a word searching task in a room with different numbers of
plants on each condition. The results showed that there was no significant difference
in productivity, stress and attention among four conditions. Significant differences
were found in the subject’s perception of friendliness, comfort, freshness, and
cleanliness of the workplace.
Keywords: indoor foliage plant; productivity; stress; attention
1. Introduction
People spend a large amount of time in their workplace. In order to
make their workplace more pleasant, people put plants, such as flowers or
foliage plants in rooms. The availability of plants in a room not only makes
the room more visually attractive, but also makes the air in the room fresher
by lowering the level of pollutants, such as formaldehyde [1], benzene [2]
and toluene [3]. Contact with plants is believed to be restorative to the
human spirit [4]. Therefore, human attitudes, behaviors and physiological
responses were affected by interaction with plants [5].
Number of researches on the benefits of indoor plants to improve
indoor air quality and its effect on humans has been increased. However, the
results were varied. Some positive results were found, such as an increase in
productivity [4], reduction in stress of the employee [4, 6, 7], improvement
of employee morale [8], reduction in health complaint [9], reduction in sick
leave [10], increase in satisfaction [11], and improvement on quality of
working life [11]. On the other hand, some negative results were also found
such as decrease in productivity [12] and increase in the level of perceived
stress [10]. [12] showed that subjects working in a room with no plants had
higher productivity than working in a room with 10 plants and a room with
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
22 plants. Therefore, there might be an optimal number between two
extreme numbers of plants to be placed in a room. Moreover, [10] showed
that an increase in the number of plants placed 1 meter from the subject
would increase the level of perceived stress.
These differences in results might be caused by differences in the
method adopted by each researcher, such as differences in the task, in
acclimatization time, in work duration, in the number of plants, in the size
of plants and also the arrangement of plants. A study on task design,
acclimatization time and work duration of indoor plant research has been
shown by [13].
The objective of the present study is to investigate the effects of the
number of plants on human productivity, attention and level of stress. In the
present study, a laboratory experiment was conducted where subjects were
instructed to conduct a word searching task in a climatic room with different
numbers of plants in each condition. To measure productivity, the number
of forms and the number of words found were used as the dependent
variable. To measure attention, a secondary task reaction time (STRT) was
applied. [14] suggested that STRT can be used to measure attention. To
measure the level of stress, heart rate change between heart rate before the
task and heart rate after the task was used. To understand further the effect
of the number of plants on productivity, attention and stress, a questionnaire
was given to the subjects.
2. Methods
Materials
Seven plants were used in the experiment. The seven plants were
aglaonema commutatum, calathea concinna, spathyphyllum, epiremnum
aureum, benjamin, schefflera arboricola, and areca palm. All plants were
potted and were placed on the table and on the floor. Plant heights were
varied from 20 cm to 120 cm.
Numerous papers containing numerous alphabet characters were used
for the word-search task. The objective of the task was to finish as many
papers as the subject could do.
Facility
The experiment was conducted in Toyohashi University of
Technology, in the climatic chamber of the Building Environment
Laboratory, from 09:00 until 20:00, from June 6 to July 14, 2012. The space
of the chamber was 3.57 meters in length, 2.67 meters wide, and 2.44
meters high. The illuminance on the desk was 408 Lux, from two
fluorescent lamps and without daylight.
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
Subjects
18 subjects participated in the study, with volunteer or unpaid basis.
Among the 18 subjects, 10 were male and 8 were female, with age ranged
from 22-30 years old with average 23.5 years old. All participants were
university students from various departments.
Experimental conditions
Four conditions were tested during the experiment. The four
conditions were a room with no plant, one pot of plant, 3 pots of plant, and
7 pots of plant in the room. The four conditions were depicted in Fig. 1.
Measurements
Heart rate before and after performing the primary task, secondary task
reaction time (STRT), and productivity (number of forms and number of
words) were measured during the experiment. Air temperature, air
humidity, CO2 compound, and lighting condition were measured during the
experiment.
Experimental procedure
A within subject design was selected as the experimental design due to
the limited number of participants, in which all 18 subjects participated in
all conditions. However, to overcome learning bias, the sequence of
conditions which followed by the subjects was randomized.
Before performing the task, the subject was given 10 minutes for
acclimatization with room condition. After 10 minutes, the heart rate of the
subject was measured. Then, the subject performed a word search on a
form. Words on the form were in English. When a word was found, the
subject then highlighted the word. The subject was instructed to find as
many words as he/she could within 10 minutes. During the experiment, the
subject was presented with a sound signal from a laptop. When the subject
heard the signal, the subject was instructed to react to the signal by pressing
the “Enter” key. The time between the signal was launched and the “enter”
key was pressed was measured. After the task had been finished, the subject
was instructed to fill in the questionnaire for 5 minutes. Schedule of the
experiment is shown in Fig. 2.
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
a) No plant condition
b) 1 plant condition
c) 3 plants condition
d) 7 plants condition
Fig. 1. Conditions of the experiment
Fig. 2. Schedule of the Experiment
Statistical Analysis
Data for subjects tested in all conditions were compared. A repeated
measures test of the general linear model was performed to compare means
of heart rate, secondary task reaction time, and productivity of all
conditions. On the other hand, a nonparametric test of related samples
Friedman’s Two Ways Analysis of Variance by Ranks was performed to
compare data of subjects’ perception of the conditions. Statistical tests were
performed using IBM SPSS Statistics Release 20.0.0.
min
0
10
20
25
a
b
c
a = acclimatization
b = word search task
c = questionnaire
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
3. Results
Physical measures of indoor environment were presented in Table 1.
Table 1. Physical measures of indoor environment
No
plant
1
plant
3
plants
7
plants
Test of
ANOVA
Temp.,
:
SD :
24.3
0.6
24.3
0.6
24.2
0.6
24.1
0.8
F = 0.41
p = 0.70
Humid.,
:
SD :
82.9
6.5
83.4
6.5
82.1
7.5
83.3
6.4
F = 0.22
p = 0.86
CO2,
:
SD :
973.3
189.4
856.4
148.0
1017.4
228.0
933.8
251.9
F = 2.96
p = 0.06
: average SD: standard deviation
In Table 1, the results of the test of ANOVA for examining the
difference among conditions was also presented in the 6th column. There
were no significant difference in the temperature and humidity. A
significant difference was found on the CO2 level, with p value < 0.1. The
lowest CO2 was the room with 1 plant condition. However, the relationship
between the number of plants and CO2 level was unclear. From Table 1, it
also can be seen that rooms with 1 plant and 7 plants have lower amount of
CO2 than rooms with no plants and rooms with 3 plants.
Dependent variables measured in the experiment were presented in
Table 2. Averages of condition 1, 2, 3, and 4 were presented in 2nd, 3rd, 4th,
and 5th column respectively. The 7th column contained the results of the
ANOVA test, which is used for examining the averages among the 4
conditions.
Table 2. Physiological and productivity measures
No
plant
1
plant
3
plants
7
plants
Test of
ANOVA
Heart rate change,
:
SD:
2.0
3.7
3.3
6.4
3.9
5.3
2.9
5.3
F = 0.51
p = 0.67
Average of STRT,
:
SD:
1.5
0.2
1.7
0.6
1.5
0.2
1.4
0.2
F = 1.94
p = 0.18
STRT change,
:
SD:
0.0
0.3
-0.4
2.0
0.2
0.3
0.2
0.5
F = 0.94
p = 0.36
Number of papers,
:
SD:
4.9
1.6
5.0
2.7
4.8
1.7
5.3
2.2
F = 0.44
p = 0.67
Number of words,
:
SD:
42.0
14.8
45.7
26.34
42.7
17.3
44.4
20.8
F = 0.36
p = 0.72
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
During the experiment, STRT was measured 4 times, randomly. From
these measurements, the average value of STRT can be obtained. The
change of the STRT variable was used to detect any change of reaction time
during the experiment, which was obtained by subtracting the 4th
measurement by the 1st STRT measurement. Most of the averages of STRT
changes were positive, except for conditions with 1 plant. It means that the
average of the 4th STRT change was smaller than the average of the 1st
STRT change.
From Table 2, it can be seen that there was no significant difference in
the average of heart rate change, the average of STRT, the average of STRT
change, average number of paper and average number of words among
conditions, as the p values were larger than 0.05 or 0.1. Although the room
with 7 plants was better on several variables than the other conditions, it
was difficult to draw any conclusion based on the data on each condition
due to the large standard deviation.
Questionnaire results
Perceptions of the participant on their physical condition, motivation
and subjective feeling of the room are shown in Fig. 3.
Fig. 3. Subject’s Perceptions of the Room
0
1
2
3
4
Physical
condition
Motivation
Feeling of
Temperatur
e
Feeling of
Humidity
Thermal
Satisfaction
Air Quality
Friendliness
Comfort
Freshness
Cleanliness
No plant
1 plant
3 plants
7 plants
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
From Fig. 3, it can be seen that physical condition, motivation, feeling
of temperature, humidity, thermal satisfaction and air quality among
conditions were not significantly different (p values were larger than 0.05 or
0.1). It can also be seen from Fig. 3 that significant differences were found
in the perception of the subjects on friendliness, comfort, freshness, and
cleanliness of the conditions (p < 0.05). From Fig. 3, it can be seen that
rooms with plants were perceived better than no plant condition. It also can
be seen that the room with seven pots of plant has the largest area than the
other experimental conditions. It suggests that the room with seven pots of
plants was perceived best by the participants.
4. Discussion
Productivity
The result showed that there was no significant difference in the
number of paper and the number of words among conditions. However,
from Figure 4, it is clear that the room with 7 indoor plants had higher
productivity than no plant condition. It seems that 7 was the optimal value
for the number of plants, as decreasing or increasing the value would reduce
the productivity. Larsen [7] suggested that the room with 10 plants and 22
plants had lower productivity than the room without any plant.
Stress
The result showed that there was no significant difference in heart rate
change among conditions. The insignificance might be caused by the high
standard deviation of data. However, it is difficult to understand the cause
of the high standard deviation of data of heart rate change. The high
variability in heart rate change data might be due to the fact that for some
participants the task was not so difficult, not fatiguing, and not stressful,
although the duration was appropriate. Some of the subjects said that the
task was interesting and challenging, therefore some of them wouldn’t look
stressed by the task. This finding confirms that plants had rather weak
effects on stress measures and not always statistically significant as
suggested by [4], [6], [8], and [10].
Attention
The result showed that although the room with seven plants condition
was better in the average of secondary task reaction time than the other
conditions (Table 2), this was not significant enough (p = 0.18). The result
suggested that this might be that the subject still have enough resources to
pay attention at the secondary task without being tied up to the primary task.
The small value of STRT change (from -0.4 to 0.2 second) suggests that
attention of the subject was not changed significantly during 10 minutes of
the experiment. Therefore, a further study with a longer working time is
required, so that attention change and fatigue can be observed.
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
Although not statistically significant, it can be seen from the mean
value in Table 2 that the room with seven plants was superior to the other
conditions. The room with seven plants condition has the lowest average of
secondary task reaction time, the highest number of forms finished, and the
second highest number of words found. Therefore, the room with seven
plants was best for participants’ productivity and attention This was also
supported by the fact that the room with seven plants condition was
perceived as the most friendly, the most comfort, the most fresh, and also
the most clean among the other conditions, as shown in Fig. 3. Compared to
the results of [4] and [12], our findings support the idea that the presence of
plants may increase worker productivity and worker attention in tasks
requiring moderate concentration, and improve the feeling on the
environmental quality.
However, due to relatively small sample size, determining whether
these differences in perception are as a result of the number of the plants or
random variation is difficult. The differences found in this study were from
hypothesis generating study. Therefore, a study with larger sample size is
required. Moreover, as the subjects in this study were mainly students, a
further study with more variations in the demography of the subjects is also
considered.
As the task carried out by the subject in the experiment is a visual
search, lighting factor is also important. Also, plants need light to grow and
for photosynthesis, so that they can absorb CO2 and release O2. In this
experiment, however, the level of light is almost the same throughout the
experiment days, as no daylight is used in the experiment, and the source of
light was only two fluorescent lamps, the same for every treatment.
Therefore, the results of the present study are not affected by lighting
condition.
5. Conclusion
In the present experimental study, the following question was
addressed: how is the effect of the number of the indoor foliage plants on
productivity, stress and attention? After carefully controlling other physical
factors and designing tasks appropriate for the study [13], we found that the
effects of the number of indoor foliage plants on productivity, stress and
attention were not statistically significant.
Subject’s perception in temperature, humidity, thermal satisfaction and
air quality among conditions was also not significantly different. On the
other hand, differences in subjects’ perceptions in the friendliness, comfort,
freshness, and the cleanliness of the room were statistically significant. The
best number of plants that should be placed in a room sized 9.53 meters
squared was seven. However, as it is not easy to determine whether these
CLIMA 2013, Prague, Czech Republic, June 16-19, 2013
differences are due to the number of plants or simply the chance, a further
confirmatory study with larger sample size is required.
6. Acknowledgement
This study was funded by Directorate General of Higher Education,
Ministry of National Education, Indonesia. All plants used in this study
were provided by PLANET Co. Ltd. Japan.
7. References
[1] Wolverton, B. C., McDonald, R. C., & Watkins, Jr., E. A. (1984). Foliage Plants for
Removing Indoor Air Pollutants from Energy-efficient Homes. Economic Botany, 38(2), 224-
228.
[2] 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, 193-207.
[3] Matsumoto, H., & Yamaguchi, M. (2007). Experimental Study on the Effect of Foliage
Plants on Removing Indoor Air Contaminants. CLIMA 2007 Well Being Indoors (p. A03
1275). Helsinki, Finland: FINVAC.
[4] Lohr, V. I., Pearson-Mims, C. H., & Goodwin, G. K. (1996). Interior Plant May Improve
Worker Productivity and Reduce Stress in a Windowless Environment. J. Environ. Hort 14 (2),
97-100.
[5] Relf, D. (1990). Psychological and sociological response to plants: Implications for
horticulture. HortScience 25:11-13.
[6] Coleman, C. K., & Mattson, R. H. (1995). Influences of Foliage Plants on Human Stress
during Thermal Biofeedback Training. HortTechnology 5 (2), 137-140.
[7] Ulrich, R.S., Simons, R.F., Losito, B.D., Fiorito, E., Miles, M.A., Zelson, M. (1991). Stress
Recovery during Exposure to Natural and Urban Environment. J. Environ. Psychol, 11:201-
230.
[8] Chang, C.-Y, & Chen, P.-K. (2005). Human Response to Window Views and Indoor Plants
in the Workplace. HortScience 40 (5), 1354-1359.
[9] Fjeld, T. (2000). The Effect of Interior Planting on Health and Discomfort among Workers
and School Children. HortTechnology 10 (1), 46-52.
[10] Bringslimark, T., Hartig, T., & Patil, G.G. (2007). Psychological Benefits of Indoor Plants
in Workplaces: Putting Experimental Results into Context. HortScience 42 (3), 581-587.
[11] Dravigne, A., Waliczek, T.M., Lineberger, R.D., & Zajicek, J.M. (2008). The Effect of
Live Plants and Window Views of Green Spaces on Employee Perceptions of Job Satisfaction.
HortScience 43 (1), 183-187.
[12] Larsen, L., Adams, J., Deal, B., Kweon, B.-S., & Tyler, E. (1998). Plants in the
Workplace, The Effects of Plant Density on Productivity, Attitude, and Perceptions.
Environment and Behavior 30 (3), 261-281.
[13] Jumeno, D., & Matsumoto, H. (2012). Characteristics of Tasks in Researches of the
Effects of Foliage Plants on Attention and Human Performance. The 9th ISAIA: Technological
Advancement in Architecture, p. A-3-4, 22-25 October 2012. Gwangju, South Korea.
[14] Lang, A., Bradley, S.D., Park, B., Shin, M., & Chung, Y. (2006). Parsing the Resource
Pie: Using STRTs to Measure Attention to Mediated Messages. Media Psychology, 8, 369-394.
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A job satisfaction survey was posted on the Internet and administered to office workers in Texas and the Midwest. The survey included questions regarding job satisfaction, physical work environments, the presence or absence of live interior plants and windows, environmental preferences of the office workers, and demographic information. Approximately 450 completed responses were included in the final sample. Data were analyzed to compare levels of job satisfaction of employees who worked in office spaces with live interior plants or window views of exterior green spaces and employees who worked in office environments without live plants or windows. Statistically significant differences (P < 0.05) were found regarding perceptions of overall life quality, overall perceptions of job satisfaction, and in the job satisfaction subcategories of "nature of work," "supervision," and "coworkers" among employees who worked in office spaces with live interior plants or window views and those employees who worked in office environments without live plants or windows. Findings indicated that individuals who worked in offices with plants and windows reported that they felt better about their job and the work they performed. This study also provided evidence that those employees who worked in offices that had plants or windows reported higher overall quality-of-life scores. Multivariate analysis of variance comparisons indicated that there were no statistically significant differences among the categories of "age," "ethnicity," "salary," "education levels," and "position" among employees who worked in offices with or without plants or window views. However, there were gender differences in comparisons of males in that male participants in offices with plants rated job satisfaction statements higher when compared with males working in offices with no plants. No differences were found in comparisons of female respondents.
Experimental Study on the Effect of Foliage Plants on Removing Indoor Air Contaminants
Article
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The objective of this paper is to demonstrate an ability of foliage plants quantitatively to remove chemical contaminants by experiments using a small desiccator for the different kinds of plant under the different luminescence and light sources, fluorescent, incandescent and light-emitting-diode (LED) lamps. The foliage plants, Benjamin, Spathiphyllum, Areca palm and Concinna, cultivated in hydroponics were used. As a result of the experiments, the effective performance of contaminant removal was obtained under lighting conditions with the different intensity distribution by wavelength for the case of pulse injection of toluene into the chamber without ventilation. The removal efficiency of toluene under an incandescent light was larger than that under a fluorescent lamp. The different removal efficiency was obtained according to the kind of LED with different intensity distribution and foliage plants. The blue LED lamp showed the highest removal efficiency among the LED lamps evaluated in this study.
Characteristics of Tasks in Researches of the Effects of Foliage Plants on Attention and Human Performance
Conference Paper
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  • May 2012
Research on the benefit of plants in workplace has been increased in the last 30 years. In some researches the presence of plants are beneficial such as reducing sick building syndrome by removing indoor air pollutants, reducing the feeling of job pressure and increasing job satisfaction, increasing productivity and reducing stress, and reducing health complaint of workers. But, in other research the benefit of plants for the task were not significant to the attention and satisfaction, concentration and number of errors, blood pressures and skin temperatures, mood and preference, and attention capacity. Moreover, in the other research plant also found bring negative effects on the task carried by human such as decrease in performance, and stress perception. In each research, there were different tasks carried out, such as test of reaction time, sorting, letter identification, association, addition, typing, memory, reading span, proofreading and so on. The effects of foliage plants on these tasks were varied. This variation of effects made the judgment and generalization of the effects of foliage plant on human attention, mood and performance become difficult. Therefore, to understand better the effect of foliage plant on various human tasks, it is required to identify which are general factors owned by the tasks affected by foliage plants, to analyze factors that differentiate one class and the other class. This paper analyzes the characteristics of tasks used in research on the effect of foliage plants on human performance. Using this understanding, a framework for task design using plants as source of visual stimulation environment is proposed.
Plants in the WorkplaceThe Effects of Plant Density on Productivity, Attitudes, and Perceptions
Article
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This experiment measures the effects of indoor plants on participants' productivity, attitude toward the workplace, and overall mood in the office environment. In an office randomly altered to include no plants, a moderate number of plants, and a high number of plants, paid participants (N = 81) performed timed productivity tasks and completed a survey questionnaire. Surprisingly, the results of the productivity task showed an inverse linear relationship to the number of plants in the office, but self-reported perceptions of performance increased relative to the number of plants in the office. Consistent with expectations, participants reported higher levels of mood, perceived office attractiveness, and (in some cases) perceived comfort when plants were present than when they were not present. Decreased productivity scores are linked to the influence of positive and negative affect on decision making and cognitive processing.
Interior Plants May Improve Worker Productivity and Reduce Stress in a Windowless Environment
Article
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  • Nov 1995
This study documents some of the benefits of adding plants to a windowless work place - a college computer lab. Participants' blood pressure and emotions were monitored while completing a simple, timed computer task in the presence or absence of plants. When plants were added to this interior space, the participants were more productive (12% quicker reaction time on the computer task) and less stressed (systolic blood pressure readings lowered by one to four units). Immediately after completing the task, participants in the room with plants present reported feeling more attentive (an increase of 0.5 on a self-reported scale from one to five) than people in the room with no plants.
Human Response to Window Views and Indoor Plants in the Workplace
Article
The purpose of this paper was to report the effects of window views and indoor plants on human psychophysiological response in workplace environments. The effects of window views and indoor plants were recorded by measuring participant's electromyography (EMG), electroencephalography (EEG), blood volume pulse (BVP), and state-anxiety. Photo Impact 5.0 was used to simulate the environment in an office, where six conditions were examined: 1) window with a view of a city, 2) window with a view of a city and indoor plants, 3) window with a view of nature, 4) window with a view of nature and indoor plants, 5) office without a window view, and 6) office without a window view and indoor plants. Participants were less nervous or anxious when watching a view of nature and/or when indoor plants were present. When neither the window view nor the indoor plants were shown, participants suffered the highest degree of tension and anxiety.
Influences of Foliage Plants on Human Stress during Thermal Biofeedback Training
Article
Twelve 20-minute thermal biofeedback sessions were conducted with 26 university students. Visual stimuli were provided by a living foliage plant, a life-sized color photograph of that plant, or a metal stool (control). Of the participants, 38% responded positively to the presence of a live plant or plant photograph, while 23% showed lower stress in the control room. Stress reduction, as indicated by higher skin temperatures, occurred within the first 5 to 8 minutes of a 20-minute thermal-biofeedback session. A nonplant visual stimulus was not part of the experiment. The results are not intended as comparative, nor do they attribute unique or superior effects to plants. Due to the small number of participants, no significant results were obtained, but the trends were important and are being reported to help further research in this area.
Psychological Benefits of Indoor Plants in Workplaces: Putting Experimental Results into Context
Article
Laboratory experiments and quasi-experimental field studies have documented beneficial effects of indoor plants on outcomes such as psychophysiological stress, task performance, and symptoms of ill health. Such studies have taken an interest in the value of indoor plants in work settings, but they typically have not considered how the effects of plants might compare with effects of other workplace characteristics. The present study makes an initial attempt to situate the potential benefits of indoor plants in a broader workplace context. With cross-sectional survey data from 385 Norwegian office workers, we used hierarchical regression analyses to estimate the associations that plants and several often-studied workplace factors have with perceived stress, sick leave, and productivity. Other variables included in our models were gender, age, physical workplace factors (e.g., noise, temperature, lighting, air quality), and psychosocial workplace factors (demands, control, social support). After controlling for these variables, the number of indoor plants proximal to a worker's desk had small but statistically reliable associations with sick leave and productivity. Although small, such associations can have substantial practical significance given aggregation over the large number of office workers over time.
The Effect of Interior Planting on Health and Discomfort among Workers and School Children
Article
ADDITIONAL INDEX WORDS. benefits of plants, foliage plants, fluorescent lighting, full-spectrum lighting, human–horticulture relationships, human issues in horticulture, human well-being, mucus membrane symptoms, neuropsychological symptoms, people–plant interactions SUMMARY. Plants are widely used in building environments; however, studies reporting the health and discomfort symptoms of people in response to indoor foliage plants are few. The objective of the presented studies was to assess the effect of foliage plants or a combination of foliage plants and full-spectrum fluorescent lamps on self-reported health and discomfort complaints in three different work environments: an office building, an X-ray department in a Norwegian hospital, and a junior high school. Health and discomfort symptoms were found to be 21% to 25% lower during the period when subjects had plants or plants and full-spectrum lighting present compared to a period without plants. Neuropsychological symptoms, such as fatigue and headache, and mucous membrane symptoms, such as dry and hoarse throat, seemed to be more affected by the treatments than skin symptoms, such as itching skin.