The VW diesel emissions scandal may be responsible for more than 40,000 tons of pollution in America, according to an analysis by the Guardian. That’s the worst-case number for emissions of nitrogen oxides, pollutants linked to environmental and health damage. The problem could be much bigger abroad, including Europe, where diesel passenger cars are far more popular than in the U.S. Eleven million VWs are under recall worldwide.

“It’s an important impact on a global basis,” said Patrick Kinney, environmental health sciences professor at the Mailman School of Public Health at Columbia University. “And just magnify it if this extends beyond VW.”