Research identifies future air quality threat from natural sources

New research at the Department of Earth and Planetary Sciences at the University of California Riverside demonstrates how global warming could make plants a future threat to air quality. And then there’s the sand…

The plant threat lies in the release of biogenic volatile organic compounds (BVOCs). James Gomez, UCR doctoral student and lead author of the study helps out here: ‘All plants produce BVOCs. The smell of a just-mowed lawn, or the sweetness of a ripe strawberry, those are BVOCs. Plants are constantly emitting them.’

Change in PM2.5 surface concentration after 4 degrees C of warming. Black dots symbolize statistically significant changes.

In and of themselves, BVOCs are no danger but once they react with oxygen they produce organic aerosols which are a danger, causing infant mortality, childhood asthma and lung cancer in adults.

The emissions of BVOCs by plants is increased by both the presence of CO2 and temperature – both of which have been on an upward trajectory for decades.

James Gomez is quick, however,  to assuage unnecessary fears about going into the garden: ‘Your lawn, for example, won’t produce enough BVOCs to make you sick,’ he explained, ‘and to be clear, growing plants is a net positive for the environment as they reduce the amount of carbon dioxide in the atmosphere. It’s the large-scale increase in carbon dioxide that contributes to the biosphere increasing BVOCs, and then organic aerosols.’

The research also studied the impact of Saharan sand on future air pollution. Robert Allen, associate professor of Earth and Planetary Sciences at UCR and co-author of the study said: ‘In our models, an increase in winds is projected to loft more dust into the atmosphere.’

As the climate warms, increased Saharan dust is likely to get blown around the globe, with higher levels of dust spreading across Africa and to the eastern U.S. and the Caribbean. Simultaneously, the amount of dust over Northern Africa is likely to increase due to more intense West African monsoons.

The study found that naturally sourced PM2.5 pollution increased in direct proportion to CO2 levels. Gomez said: ‘The more we increase CO2, the more PM2.5 we see being put into the atmosphere.’

The survey predicts that an increase in global temperatures by 4°C will increase PM2.5s from harmful plant emissions and dust by as much as 14%.

He concludes: ‘The results of this experiment may even be a bit conservative because we did not include climate-dependent changes in wildfire emissions as a factor. In the future, make sure you get an air purifier.’