Potted plants remove pollution

Categorie(s): City life, Health

Plants can remove a dangerous and general type of air pollution, that often occurs inside. 

Nitrogen dioxide is a gas that is produced  by car traffic, and other factors. It influences the air quality quite badly, not only outside, but also inside houses, especially when situated near busy streets. And this can affect  people’s health. Exposure  to nitrogen dioxide has been connected with serious  problems of the bronchial tubes and deminished functioning of the lungs. Now scientists have found a very attractive way to lower the concentration of nitrogen dioxide inside:  potted plants! Experimnents suggest that potted  plants can reduce the concentration of nitrogen dioxide  by as much as 20%!

Popular plants

The scientists worked with several popular species; maybe you have one or more of them in your own  window sill. They worked with   Spathiphyllum wallisii, known as ‘peace lily’ and  Dracaena fragrans (‘fragrant dracaena’) and  Zamioculcas Zamiifolia (‘zanzibar gem’, or ’emerald palm’).

Dracaena reflexa, also a good cleaner!>

 

 

The experiments

Each plant was placed – alone – in a testing room. In that room the concentration of nitrogen oxide  was the same as in an office space  ajoining a busy road. Within one hour each plant –  each tested species and both in light and darkness, and placed in wet or dry soil –  had removed about half of the nitrogen dioxide from the air in the testing room.

The researchers also calculated what these plant could achieve in a small office (15 m3) with badly polluted air and poor ventilation. In a room like that 5 plants could  remove up to 20% of the NO2 from the air. In bigger spaces (100 m3) the effect of the same number of plants was much less: five potted plants could remove about 3,5%. But  more plants placed in such a room can have a bigger effect.

Surprising

These results are quite surprising. “The plants we have chosen are very different, but their capability to remove nitrogen dioxide  was  surprisingly equal,” says Christian Pfrang, one of the scientists, “It also differs a lot from the way the plants remove CO2 from the air,  for that depends a lot of  factors like day or night, wet or dry soil.”

Unexplainable

This raises the question how the plants remove the nitrogen dioxide from the air. Just now the scientist have no answer, says Pfrang. “We do not think it is the same process as the uptake of CO2, in which the gas is absorbed via the stomata – small holes – in the leaves .  There is also no evidence that  the plants return the gas to the air, even not in longer lasting experiments. Probably there is a biological proces in which the soil also plays a role, but we do not know which proces works here.”

Further experiments must tell us how de plants are able to remove the nitrogen dioxide from the air and make the air a bit healthier for us. When waiting for the explanation is seems  a good idea to have some more  potted plants – or  give your collection of plants a bit more love and the appreciation they deserve — as this study shows.

NB: A list of plants that are the best air cleaners you find here

Author: Caroline Kraaijvanger

Source: Scientias,   March 2022