Indoor plants can remove toxic petrol fumes from indoor air, according to a world-first study by researchers at the University of Technology, Sydney.
Concerned by recent research indicating that up to 66,000 cases of childhood asthma and 10,000 deaths in Australia are attributable to air pollution, UTS and indoor plant provider Ambius collaborated on a study to examine the effectiveness of indoor plants in removing pollutants from the air.
Ambius general manager Johan Hodgson described the results as “astounding” at a press conference at a UTS science laboratory on Thursday.
Indoor plants removed nearly all the volatile organic compounds (VOCs) from petrol vapour from the air within eight hours, beginning with the most toxic substances. The plants removed 97.9 per cent of alkanes, which are harmful to lungs, 88.18 per cent of cyclopentanes and 85.96 per cent of benzene derivatives, which can disrupt normal blood production.
The researchers measured the impact on plants in sealed chambers where petrol vapours were applied and then tested at regular intervals.
Lead researcher Dr Fraser Torpy said bacteria in the soil break down the pollutants. He said indoor air is around two to five times more polluted than outdoor air, and the potential for plants to improve air quality was significant given that we spend 90 per cent of our time indoors.
Previous studies had examined the potential for plants to move a broad range of air contaminants, but this was the first study to explore petrol vapours.
Hodgson said plants had other biophilic properties such as lowering anxiety and negative feelings, helping us feel more connected with nature, regulating temperature and humidity.
The researchers also found that plants became more efficient at removing toxins as they became more concentrated in the air, showing their ability to adapt to the conditions they are growing in.
Hodgson said it was important to select the correct plants for a given level of light present in indoor environments to allow them to photosynthesise, because they can only generate the bacteria to feed on the pollutants if they are healthy.
Benzene is the most carcinogenic pollutant that humans are exposed to from vehicle emissions, and the majority of exposure humans receive is in indoor garages. If garages are connected to houses or apartments, the pollutants can escape and end up in indoor living environments.
“When we looked at the consequences of benzene exposure, we found a three to 21 per cent elevated risk of cancer in people are exposed to this benzene. So, we’ve got a problem. And it’s a problem that people aren’t talking about,” Torpy said.
He added that the researchers tested soil with no plants growing in it to see if it could also remove the pollutants. The soil was effective for around two weeks, but the bacteria then died off and the process stopped working. “So you can’t just have a bag of dirt, you’ve got to have the plant in there,” he said.
Hodgson said some plant species were more effective at removing pollutants than others, but that the best solution was to “have more plants. One variety might be 5 per cent better than another, but if you have two plants then it’s a 200 per cent improvement.”