This was only one study, there is much more evidence however that indoor plants are perceived as an integral and important element of indoor spaces. Again it is somewhat subjective, but strong support is given by the preponderance of new public buildings devoting more time, thought, energy and expense on the indoor plant displays. Rest assured that as many of these buildings are commercial enterprises they would not be so keen to pay such careful attention to the indoor landscape if they felt that there was no economic benefit to be gained. As stated, there is little quantifiable evidence to support the idea of the indoor landscape providing economic benefits, but some educated guesses can be made to explain how it might play a role.
Referring to the above list, the public would feel more welcome, more relaxed, less stressed and happier in an environment with indoor landscaping. As such when given the choice, they are more likely to select the more comfortable and welcoming environment.
Indoor plants contribute in a number of ways to improving the indoor environment. Live plants in particular due to the physiology relating to their growth processes. (Artificial plants or preserved plants can also provide some benefits such as reducing background noise, hiding ugly features, highlighting/enhancing key features or areas and to delineate areas or assist with zoning and breaking up large open spaces, but live plants can provide these and much more).
The indoor environment can vary hugely depending on the building’s purpose and design. In the United Arab Emirates, many public buildings have a large preponderance of glass which lets in a lot of light (and heat). This is combated by the ubiquitous use of air conditioning. Air conditioning in turn adversely affects the air quality, making it drier.
Crowded indoor public spaces can also suffer from elevated carbon dioxide levels created through human biological processes namely breathing, and to a lesser extent from the by-products of electrical equipment.
In buildings that are too dry and have high carbon dioxide levels, people often tend to feel a little lethargic. (With regard to humidity, 40% – 60% RH is the optimal value for human comfort).
Plants whilst actively photosynthesizing, extract carbon dioxide from the air and produce oxygen as a natural by-product of growth. They also release water vapour naturally through pores called stomata in their leaves during transpiration. Both these factors can contribute to improving the indoor environment.
An associated benefit to plant transpiration is the evaporative cooling effect that occurs during the process. Heat is transferred to the evaporating vapour at the leaf surface and removed from the surrounding air.
Plants are also associated with reducing dust in interiors. It has been suggested that dust particles are attracted to and stick to plant leaf surfaces.
Interior spaces with a preponderance of hard reflective surfaces can benefit from the introduction of plants, which can help to reduce background noise.
Hiding unattractive building elements
Indoor plant displays can be used to combine aesthetic qualities whilst serving a useful purpose. Most interior spaces, no matter how well designed have areas that are visually unattractive, such as baggage storage areas in hotels/airports, service entrances, etc. these can be screened or softened with carefully positioned plant arrangements.
In the case of a shopping mall, this would bring the public into close proximity of the outlets within the landscaped mall which would undoubtedly benefit the outlets. The mall owners, in turn, would benefit from being able to charge a premium for space within the mall. In a more relaxed atmosphere, the public are likely to spend more time at the mall and are therefore exposed to a potential spending spree in a better frame of mind than would otherwise be the case.
In the workplace
It is now strongly supported by research and observation that high quality plants can play a significant part in reducing absenteeism from the workplace. The reasons are unclear, but it is likely that many of the factors are a subtle combination of the subliminal effects described above, namely, improved air quality, reduction of noise and the aesthetic quality of the displays themselves. All these factors contribute to a better sense of well being, reduced stress levels and open the way for a more relaxed workforce, better able to focus on the task at hand.
The fact that an employer has taken the time to consider their employees and has been willing to invest in their sense of comfort in the workplace may also play a factor by passing the message that “senior management does care”.
There is no evidence to support the idea that filling every available space with a plant is necessary to achieve the desired result. On the contrary strategic placement of high-quality plants is thought to be more beneficial. Areas to target include; in close proximity to workstations, and in areas where staff congregate to relax and take breaks. In fact, fewer can be better if attention is paid to the type of plant used and its position.
Guidance and identification
Plants can be useful in large spaces to help the functionality of the space providing attractive indoor “landmarks”. They can be used to break up spaces and provide subtle ways of indicating directional movement. They can also be used to mark specific areas, for example, information desks, bathrooms etc. Direction to such places which may be difficult to find in a large area could be made easier if someone giving direction can say “it’s behind the large tree in the red pot”.