Research and Results

NASA Clean Air Study
The NASA Clean Air Study has been led by the National Aeronautics and Space Administration (NASA) in association with the Associated Landscape Contractors of America (ALCA). Its results suggest that certain common indoor plants may provide a natural way of removing toxic agents such as benzene, formaldehyde and trichloroethylene from the air, helping neutralize the effects of sick building syndrome. The first list of air-filtering plants was compiled by NASA as part of a clean air study.

Dr Bill Wolverton conducted early research for NASA (early 1990’s, book first published 1996) to prove that plants absorbed toxins from the air around them, translocated it to their roots, where organisms turned the toxins into food for the plant. Wolverton published a book after his research naming a number of plants which are accepted as the most effective.

Andrew Smith, School of the Built Environment, John Moores University, Liverpool (2008) found that plants reduced CO2 by 50% in a planted open plan office.

Andrew Smith’s (School of the Built Environment, John Moores University, Liverpool 2008) study (UK) found that absenteeism was reduced by 50% in a planted office.

Tina Bringslimark, University of Agriculture, Oslo, Norway (2008) found that office workers reported less stress related sickness when they saw several plants from their desks.

Prof Roger Ulrich, Texas A & M University, USA (1984, 91, 92, 99 & 2001) found that plants or even green views decreased stress levels of recovering surgical patients assisting faster recovery.

Nancy Wells, Cornell College of Human Ecology, University of Michigan (2002) showed that children brought up in greener surroundings had better cognitive ability and concentration.

Craig Knight, University of Exeter (2009) showed evidence that enriched work environments can improve productivity by more than 15%. If the employees themselves had a say in the enrichment,then productivity improved by as much as 30%.

A research project carried out by Fjeld in a school in Oslo involved 61 pupils and 8 teachers with planted classrooms and 59 pupils and 2 teachers in unplanted classrooms was carried out over a two year period.

The outcome: Pupils also reported a positive appreciation for the plants, reporting that their classrooms felt fresher, generally more pleasant and attractive. These results confirm earlier findings from similar research carried out in an office environment.

A 35 % lower concentration of volatile organic compounds was found in classrooms with plants. An added bonus for the occupants of the planted classrooms:

  • 47% reduction of headaches
  • 37% reduction of dry or hoarse throats.
  • 69% claimed they 'felt' better generally.
  • Cold sufferers complained less of the symptoms.
  • Rooms were perceived as bigger.