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Task 4 (index)






Plants at working places


It has been shown through studies that plants at working places improve the indoor air quality by reducing the levels of VOCs. But at the same time, they also improve productivity by up to 12% according to some studies. They reduce the absenteeism and the staff turnover cost. Besides they are likely to improve health and well-being of the workers.




1) Productivity and indoor plants


A study in The Netherlands in 2001, has involved 250 employees separated into two groups : a control group, without plants and a test group with plants. The researchers found that :

                             - the test group rated well-being more favourably than the control group

                             - the same applied to the ratings for the quality of the working area

                             - the differences that were found were more explicit for the group of employees who work more than 4 hours a day in front of a computer screen

                             - their productivity improved, especially in terms of efficiency

                             - the strongest link was found with those working at computer terminals in the experimental group, particularly for quality of the working environment and well-being

                              - loss of concentration dropped, that is to say concentration improved in the test group

                              - no findings with regard to any significant improvement in health

In that way, indoor plants were found to be beneficial for the productivity at work.


2) Health and well-being and indoor plants

In 1993, a Swedish study concluded that if office personnel could view greenery through their office windows, significantly stress was reported during the working day, compared with office workers who had views to non-vegetated areas, such as streets and parking lots.

In an other research carried out in 1998 in Norway, 51 offices were tested over two three-month periods. This study evaluated the effects of indoor plants on health and well-being of occupants, finding significant reductions in incidence of symptoms such as coughing (37%), fatigue (30%), dry/hoarse throat and dry or itching facial skins (23%). 

There was also a study of personnel working in a hospital radiology department. A 25% decrease in complaints was observed after the introduction of indoor foliage plants and full-spectrum lighting. Significant effects were observed especially for headache (45%), feeling heavy-headed (33%), fatigue (32%), dry, hoarse throat (22%) and dry/itching skin on hands (21%). But there were no changes observed in the concentration of fungal spores due to the introduction of plants and improved lighting. Besides, the radiology department director reported that "short-term absence due to illness decreased from a usual 15% to 5% during the experimental period, and with the plants remaining in the room this decreased rate has persisted for 5 years.

In the same way, a Norwegian study conducted in 12 school classrooms in 1999, found : 21% less health and discomfort complaints among pupils ; significantly reduced complaints regarding fatigue, feeling heavy-headed and dry, itching or irritated eyes ; higher level of satisfaction regarding the perception of the visual environment of the classroom ; no difference in the number of mould spores in the indoor air between intervened and control rooms ; lower sickness absence among junior high school pupils ; 35% lower concentration of Total Volatile Organic Compounds (TVOC) in indoor air.

Thus, by absorbing some chemical pollutants of the indoor air, house plants can improve effectively the well-being and also the health of the occupants of the room.







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Started by NIRAS supervisor Sergio Fox on 27th March 2006.


NIRAS - Aurélie