Plants protect people from colds and Covid by disinfecting the air, research shows

Plants are already highly valued for their aesthetic, mood-enhancing and climate-mitigating properties.

But it also seems like they can help us protect ourselves from colds, covid, and other viruses.

Research is still in its early stages, but one study found evidence that filling a home or office with plants can help protect against a range of bacterial and viral infections and generally keep the air clean.

Scientists at the University of Victoria in Australia have discovered that during photosynthesis, plants produce a chemical that neutralizes viruses, safely disinfecting the air.

The chemical — hydrogen peroxide, a caustic substance used to disinfect surfaces and bleach hair — spontaneously forms in microscopic water droplets in small but effective amounts that are harmless to humans.

Hydrogen peroxide was present in the water vapor given off by each of the plant species tested, although the amount varied.

African violet (English)Saintpaulia Ionanta) produced the most hydrogen peroxide of the samples tested, followed by Devil’s Ivy (Epipremnum golden).

“This is a very good conceptual study of whether plants can help decontaminate the air,” said Christian Dubravsky of the University of Victoria.

“Houseplants can help deactivate airborne disease-causing bacteria and viruses such as Covid-19.
at home and at work,” he said.

Dr. Dubravsky notes that the study has not yet been peer-reviewed, and further research is needed in this area.

But he is encouraged by his findings, which also suggest that plants “could mitigate climate change” by reducing the harmful effects of greenhouse gases such as methane, carbon monoxide and nitrous oxide in the atmosphere.

This climate benefit is in addition to the widely recognized role of trees and plants in reducing global warming by absorbing CO2.

“Our findings have the potential to have major implications for the role of plant-mediated air cleaning, climate change, and urban and indoor air quality,” he said.

“Hydrogen production by plants can affect indoor air quality (eg hospitals); Areas with high population density (such as metropolitan areas) and rural areas affected by wildfires. Our work also implies that plants are a viable natural solution for improving air quality and preventing outbreaks of pathogenic infectious diseases.

“In this study, we report initial findings on the production of hydrogen peroxide through sweat. [exhaled] water vapor and show that, surprisingly, all evaporative plants are likely to contribute to local and hence global concentrations of hydrogen peroxide in the atmosphere.

“Hydrogen peroxide produced in plant areas can … contribute to the formation of hydroxyl radicals: the central oxidizer of the lower atmosphere that controls the persistence of methane, carbon monoxide, nitrous oxide and some ozone-depleting gases.

“We report consistent production of hydrogen peroxide by different plants of the same species and by plants of different species, although different plants and different species produced different amounts. Although hydrogen production was constant, differences between plants and species were likely due to differences in photosynthesis and transpiration rates across different leaf surfaces, stomatal size, and morphology. [size, shape and structure]”.

More research is needed to determine which plant species produce the most hydrogen peroxide and why.

Transpiration is the process by which water moves through a plant and is evaporated by leaves, stems, and flowers.

Water is essential for plants, but only a small amount is taken up by the roots and used for growth and metabolism. The remaining 97–99.5% is consumed by evaporation or seeps from the plant in the form of tiny droplets.

Experts not involved in the study welcomed the results.

Richard Zare, professor of chemistry at Stanford University and an expert on hydrogen peroxide’s virus-neutralizing effects, said: “Yes, plants can help with moisture. They release solid particles that help form droplets and increase the production of hydrogen peroxide.”

Adrian Davids, an independent researcher who worked with Professor Zareh on the hydrogen peroxide study, added: “There are many reasons why having plants in your home is a good idea. One of them is the improvement of air quality through the action of hydrogen peroxide and hydroxyl radicals.

“We must draw inspiration from nature and emulate what she has created over billions of years and trillions of iterations. We have created an artificially distorted internal environment that we must recreate as closely as possible to the natural environment in which we developed and flourished. Bring in the plants. Most of the water you spill gets into the air through sweat.

Simon Williams of Swansea University has been studying people’s behavior during the pandemic.

He says: “If the amount of such evidence continues to grow, then people are likely to be much more inclined towards cheap behaviors like buying more plants than other things like wearing a mask or social distancing.”

“The challenge is to communicate to the public that things like more houseplants can improve indoor air quality and reduce the spread of airborne viruses,” he said.

University of Queensland research has provided valuable new insights into the debate about how plants can improve indoor air quality, although more research is needed to better understand this.

This helps answer a question in a 2021 paper from Alexandria University of Egypt that was published in the journal. The frontiers of molecular life sciences on whether plants could be “a potential new environmentally friendly tool to purify indoor air and reduce the spread of Covid-19 indoors.”

This suggests that “the role of plants is regulating [hydrogen peroxide-containing] Indoor humidity can be considered as an alternative solution. [to air filtration systems] which can be used to reduce the viability of Covid and increase the aesthetic value of the environment.”

But the conclusion is: “More research is needed in this area to find methods to reduce transmission rates in low-budget locations, especially since houseplants increase human comfort and improve overall human health.”