OSLO - Green schemes to fight climate change by producing more bio-fuels could actually worsen a little-known type of air pollution and cause almost 1,400 premature deaths a year in Europe by 2020, a study showed on Sunday.
The report said trees grown to produce wood fuel - seen as a cleaner alternative to oil and coal - released a chemical into the air that, when mixed with other pollutants, could also reduce farmers' crop yields.
"Growing biofuels is thought to be a good thing because it reduces the amount of carbon dioxide in the atmosphere," said Nick Hewitt, who worked on the study with colleagues from England's Lancaster University.
"What we're saying is 'yes, that's great, but biofuels could also have a detrimental effect on air quality'," he added.
The report, in the journal Nature Climate Change, looked into the impact of a European Union scheme to slow climate change by producing more biofuels.
Hewitt told Reuters there would be a similar impact wherever biofuels were produced in large quantities in areas suffering air pollution, including the United States and China.
Poplar, willow or eucalyptus trees, all used as fast-growing sources of renewable wood fuel, emit high levels of the chemical isoprene as they grow, the study said. Isoprene forms toxic ozone when mixed with other air pollutants in sunlight.
"Large-scale production of biofuels in Europe would have small but significant effects on human mortality and crop yields," said Hewitt.
"As far as we know, no one has looked at the air quality of growing biofuel crops before," he added.
The report estimated that ozone from wood-based energy to meet the European Union's 2020 goal would cause nearly 1,400 premature deaths a year, costing society $7.1 billion.
The European plan would also would reduce the annual value of wheat and maize production by $1.5 billion since ozone impairs crop growth, the study added.