Healthy and motivated employees are an organisation’s greatest asset, now more than ever before. And yet the crisis is often cause for economising on investments in buildings and personnel. Everything which is regarded as an extra is the first thing to be economised on. So what if there is a cheap and effective method to increase employees’ health and wellbeing, without it instantly involving enormous costs?

Sick buildings will result in sick employees

It may be strange to put it like this, but us human beings have only very recently evolved into beings which spend 90% of their time indoors. Plus we have managed to make these ‘dwellings’ several floors high, haven’t allowed for a great deal of natural light and equipped them with artificial air filtration. It’s no wonder people get tired and ill there, prefer to work from home and generally enjoy low performance levels.

The green revolution is in full swing. There is now an increasing realisation that people perform, heal and learn much better when there is sufficient daylight, fresh air and people-friendly spaces. But certainly not all companies, especially in the SME sector, have the means available to them to build a fantastic and new green building.

Research conducted has convincingly demonstrated that plants at the workplace, as well as at central places within buildings, do a great deal more for people and buildings than simply improve the atmosphere. Plants represent an actual contribution to healthier employees and a cleaner working climate.

  1. Plants purify the air and
  2. thereby improve people’s health.
  3. Plants improve the acoustics, especially in modern open plan offices.
  4. Plants result in demonstrably improved performance levels.
  5. Plants increase people’s general feeling of wellbeing. Research conducted in the care sector specifically shows that patients literally recover more quickly with views of or access to green.

Purifying the air

The pioneering work carried out during the nineteen eighties, when Dr Wolverton conducted research on behalf of NASA in order to find out how the air in a completely sealed space cabin could remain viable. He discovered that plants don’t just actively convert CO2 into oxygen, but that they are also capable of purifying hundreds of particulate compounds. Literally dozens of research projects subsequently carried out follow up research in order to be able to repeat this effect. The enclosed TNO Literature Study refers to the most important research conducted regarding this subject.


This diagram shows the level of impact plants can have in various different office situations. The impact is particularly spectacular when no additional air filtration is in place and specifically noticeable: the effect reduces when conventional air filtration continues to dominate!

A reduction in health complaints

We are familiar with the fact that the Sick building syndrome can cause health complaints. These can include allergies, airway problems, dry eyes and reduced concentration. This table doesn’t require any additional explanation.


Figure 3.1: Reduction of the experienced seriousness of the 12 health complaints and feelings of discomfort before and after the plants were placed at the workplace (no complaints=0, serious complaints=3) (source: Fjeld e.a., 1998)


All this different research has also been repeated in various different ways several times and always comes back with the exact same results. Plants increase the oxygen content in a room, clean the air of particulate compounds and also make the air less dry, plus humidity increases.

Plants, and green walls in particular, improve acoustics

The fact that people experience stress as a result of noise has only recently been acknowledged. This is specifically about the reverberation time within office buildings. The louder a room is, the longer the reverberation time. Plants are capable of diffusing this reverberation time. They do this with their leaves. Green walls are often used for this purpose, for example as a room divider in open plan offices.

Plants help people to improve their performance levels

So if plants can purify air, produce oxygen, mute noise and increase people’s wellbeing, then they should naturally also be able to increase performance levels. And this is exactly what they do.

This TNO research constantly placed 47 subjects, roughly from the same composition (all students), in a bare room either with none, one or several plants and asked them to carry out various skill tests.

This same group was also asked whether they were tired or stressed before they started on the tests. The improvement becomes even stronger when the results are corrected in line with this.



This research therefore shows that people don’t need many plants in order to improve their performance levels and their resilience. One plant is enough!

This same research was also repeated as field research with insurance companies and also resulted in significant improvements here. However, the results were somewhat more diffused here, as the groups of people aren’t as similar and the rooms worked in couldn’t be checked.

Plants increase people’s feelings of wellbeing

People’s wellbeing is not a factor which is easy to measure. Various different types of research have been conducted which have attempted to carry out controlled measurements, but they have remained vague results. Research conducted in the care sector, where there was actually a case of faster healing or a reduction in medication, clearly and most convincingly demonstrates the connection between green and wellbeing. The underlying theory is always that nature makes us calmer and makes us feel safer and plants in the workplace are actually a piece of nature at the workplace.


Plants do something, that much is abundantly clear, and you don’t even need many plants in order to achieve an effect. One plant per two employees or 12 m2 is enough to realise the aforementioned performance improvement. More plants will be needed in order to realise the acoustic and air purifying effects. Please note: not all plants are equally good at purifying air. You can read more on this subject in our article on the self-cultivation of fresh air.


Generally speaking, employers will deal with their employees’ wellbeing from a sustainability perspective and will subsequently place plants in the people aspect (wellbeing, health). But this website also includes some fantastic examples of office environments where sophisticated planting contributes to a significant reduction in energy consumption. This includes the isolating effect a green roof can result in or the integration of indoor planting with the air filtration. Plants increase the air purity and humidity and reduce the need for air conditioning applications.