Are plants in offices beneficial to health?

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