Five house plants in the office can cut air pollution by 20%, new study suggests

New research indicates that house plants can reduce levels of nitrogen dioxide in the air

Joanna Whitehead
Tuesday 08 March 2022 14:58 GMT
<p>Plants are renowned for their purifying qualities</p>

Plants are renowned for their purifying qualities

Five house plants in an office can cut air pollution by 20 per cent, a new study suggests.

While the purifying properties of plants is well established, the data on their efficacy has been sparse.

New research led by the University of Birmingham in partnership with the Royal Horticultural Society (RHS) suggests that just five small plants in a modestly-sized office could reduce levels of nitrogen dioxide (NO2) - a common pollutant linked to respiratory disease - by as much as 20 per cent, however.

Scientists used three inexpensive and easy-to-maintain houseplants that are commonly found in UK homes for their study: the peace lily (Spathiphyllum wallisii), the corn plant (Dracaena fragrans) and the fern arum (Zamioculcas zamiifolia).

Each plant was individually placed into a test chamber containing levels of NO2 comparable to an office situated next to a busy road.

Over the course of an hour, each of the plants were able to remove about half of the NO2 in the chamber.

Their performance was not affected by their environment, such as the level of light or whether their soil was wet or dry,

Lead researcher Dr Christian Pfrang said: “The plants we chose were all very different from each other, yet they all showed strikingly similar abilities to remove NO2 from the atmosphere.

“This is very different from the way indoor plants take up CO2 in our earlier work, which is strongly dependent on environmental factors such as night time or daytime, or soil water content.”

The team calculated that in a poorly ventilated small office (15 cubic metres) with high levels of air pollution, around five one foot high houseplants would reduce NO2 levels by about 20 per cent.

Dr Pfrang acknowledged that more testing was required, adding that mechanical filters would outperform plants when it comes to removing impurities from the air.

Dr Tijana Blanusa, a principal horticultural scientist at the Royal Horticultural Society and one of the researchers involved in the study said: “This complements RHS efforts to understand scientific detail behind what we know to be a popular passion.

“Understanding the limits of what we can expect from plants helps us plan and advise on planting combinations that not only look good but also provide an important environmental service.”

The results of the study have been published in the journal Air Quality Atmosphere & Health.

The news comes after a new analysis found that every hospital and medical centre in London is in an area the World Health Organisation (WHO) classifies as having toxic air pollution.

London Mayor Sadiq Khan called for urgent action on the “unacceptable” figures.

“Steps to tackle air pollution will also help tackle the climate crisis and I’m determined that we do everything possible to protect Londoners’ health both now and in the generations to come,” he said.

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