Indoor plants do not only look and smell nice, they could save your life, claim scientists.

New research shows that ornamental plants can drastically reduce levels of stress and ill health and boost performance levels at work because they soak up harmful indoor air pollution.

Researchers have now identified five "super ornamental plants" which every workplace should have to clean up indoor air.

They include English ivy, waxy leaved plants and ferns.

According to a World Health Organisation report in 2002, harmful indoor pollutants represent a serious health problem that is responsible for more than 1.6 million deaths each year.

Indoor air is up to 12 times more polluted than outdoor air in some areas, with air quality affected by chemicals from paints, varnishes, adhesives, furnishings, clothing, solvents, building materials and even tap water.

These produce so-called volatile organic compounds, or VOCs, that have been shown to cause illnesses in people who are exposed to the compounds in indoor spaces.

Now horticulture experts in the US have tested a number of ornamental indoor plants for their ability to remove harmful VOCs from indoor air.

Stanley Kays, the lead researcher at University of Georgia, said some indoor plants have the ability to effectively remove harmful VOCs from the air and not only improve physical health, but also someone's wellbeing.

Adding these plants to indoor spaces can reduce stress, increase performance at work and reduce symptoms of ill health.

The research team tested 28 common indoor ornamental plants for their ability to remove five volatile indoor pollutants.

Of the species tested, purple waffle plant (Hemigraphis alternata), English ivy (Hedera helix), waxy leaved plant (Hoya carnosa) and Asparagus fern (Asparagus densiflorus) were rated best for removing air pollutants.

The purple heart plant (Tradescantia pallida) was rated superior for its ability to remove four of the VOCs.

Prof Kays, writing in the journal HortScience, said: "The volatile compounds tested in this study can adversely affect indoor air quality and have a potential to seriously compromise the health of exposed individuals."

The study concluded that simply introducing common ornamental plants into indoor spaces has the potential to significantly improve the quality of indoor air.

Prof Kays said: "As well as the obvious health benefits, the increased use of indoor plants in both 'green' and traditional buildings could have a tremendous positive impact on the ornamental plant industry by increasing customer demand and sales."