Like a lot of other chemicals, ozone can be both useful and harmful. In the planet’s stratosphere, it protects us against harmful UV rays. Any lower, however, it can cause respiratory illnesses and hurt the growth of plants.
No wonder then that governments around the world would like to regulate the amount of ozone that is spewed in the atmosphere. The US has been tightening laws to control the creation of ozone pollution over the past decades. Sadly, according to a new study, China’s growth has offset nearly half the reductions the US has achieved.
Winds blowing from the west to east carry ozone and other precursors, such as nitrogen oxides (NOx), from China to the US. The study, published in Nature Geoscience, calculates that these winds offset as much as 43% of the improvements in air quality expected in the western US in response to tighter regulations.