Plants better than tech for reducing air pollution: Study

New York: Plants and trees may be better and cheaper options than technology to mitigate air pollution, says a new study from an Indian-origin researcher.

The study, published in the journal Environmental Science & Technology, found that adding plants and trees to the landscapes near factories and other pollution sources could reduce air pollution by an average of 27 per cent.

Researchers found that in 75 per cent of the countries analysed, it was cheaper to use plants to mitigate air pollution than it was to add technological interventions - things like smokestack scrubbers - to the sources of pollution.

"The fact is that traditionally, especially as engineers, we don't think about nature; we just focus on putting technology into everything," said Indian-origin researcher and study lead author Bhavik Bakshi from the Ohio State University.

"And so, one key finding is that we need to start looking at nature and learning from it and respecting it. There are win-win opportunities if we do - opportunities that are potentially cheaper and better environmentally," he added.

To start understanding the effect that trees and other plants could have on air pollution, the researchers collected public data on air pollution and vegetation on a county-by-county basis across the lower 48 states.

Then, they calculated what adding additional trees and plants might cost.

Their calculations included the capacity of current vegetation - including trees, grasslands and shrublands - to mitigate air pollution.

They also considered the effect that restorative planting - bringing the vegetation cover of a given county to its county-average levels - might have on air pollution levels.

They estimated the impact of plants on the most common air pollutants - sulfur dioxide, particulate matter that contributes to smog, and nitrogen dioxide.

They found that restoring vegetation to county-level average canopy cover reduced air pollution an average of 27 per cent across the counties.

Their research did not calculate the direct effects plants might have on ozone pollution, because, Bakshi said, the data on ozone emissions is lacking.

They found that adding trees or other plants could lower air pollution levels in both urban and rural areas, though the success rates varied depending on, among other factors, how much land was available to grow new plants and the current air quality.

The findings indicate that nature should be a part of the planning process to deal with air pollution, and show that engineers and builders should find ways to incorporate both technological and ecological systems.