EarthA mix-up means US air pollution is way worse than thought Levels of nitrogen oxides in the air are still falling across the US, but satellite measurements show the reduction has slowed down unexpectedly since 2011 51¶¯Âþ
EarthThese strange lines of cloud are seeded by pollution from ships Much as an aeroplane leaves contrails, streaks of white cloud condense onto the tiny particles thrown into the air by the exhausts of travelling ships Regulars