Houseplants offer limited benefits when it comes to improving indoor air quality, according to experts, who emphasize that ventilation remains the most effective way to maintain fresh air in homes and workplaces. While plants do absorb carbon dioxide and release oxygen through photosynthesis, the scale of their impact is often overstated.
John Tregoning, a professor at Imperial College London and author of *Live Forever? A Curious Scientist’s Guide to Wellness, Ageing and Death*, explains that the oxygen output of a typical houseplant is minimal. "The average plant produces just a few litres of oxygen a day," he said. By comparison, a single person consumes around 500 litres of oxygen daily. To meet the oxygen needs of one individual solely through plants would require hundreds of them, as well as ample light to sustain photosynthesis. He added that excessively high oxygen levels indoors could actually be harmful.
Tregoning stresses that while people’s concerns about indoor air quality are valid, plants should not be seen as substitutes for proper ventilation. Environments with poor airflow, especially those crowded with people, can lead to elevated levels of carbon dioxide, which may cause drowsiness. Additionally, inadequate ventilation can facilitate the spread of colds and other illnesses.
Instead of relying on plants, the expert advises ensuring regular air exchange by opening windows or using mechanical ventilation systems. This helps reduce the concentration of carbon dioxide and other indoor pollutants, creating a healthier atmosphere.
Despite their limited role in air purification, plants and trees can still contribute positively to wellbeing. Tregoning references a study from the 1980s involving hospital patients recovering from surgery. Those placed in a ward with windows overlooking trees required less pain medication and experienced quicker recovery times compared to patients in a ward facing a brick wall. Such findings suggest that the presence of greenery may have beneficial psychological or physiological effects, even if their direct impact on air quality is minimal.
In summary, while houseplants provide some aesthetic and minor health benefits, they do not significantly improve indoor air quality. Proper ventilation remains the most reliable method to ensure fresh and healthy indoor environments.