A mix-up means US air pollution is way worse than thought

New Scientist

Image: faungg’s photos

Air pollution levels are falling in the US – but not as rapidly as the US Environmental Protection Agency thinks they are.

The US has been reducing its emissions of nitrogen oxides (NO_x) and carbon monoxide for about 50 years. The EPAkeeps tabs on the progress, in part by calculating how technological improvements should change the emissions from vehicles and factories.

But those calculations seem to be overestimating the progress being made, according to Zhe Jiang at the University of Science and Technology of China in Hefei. While at the National Center for Atmospheric Research in Boulder, Colorado, Jiang and his colleagues examined pollution data from satellites and ground-based sensors.

The team found that NO_x concentrations in the air dropped by 7 per cent each year between 2005 and 2009 – but by only 1.7 per cent each year between 2011 and 2015. That’s a 76 per cent slowdown. The EPA’s figures estimate the slowdown should have been just 16 per cent. Read more on newscientist.com…