New research from Columbia climate scientists shows that the 1987 ozone treaty, designed to protect the ozone layer, has postponed the occurrence of the first ice-free Arctic by as much as 15 years.

Climate change could worsen China’s already bad ozone pollution problem — but a new study shows that it doesn’t have to be that way.

“It’s a code red day for ozone.” If you hear this on your local news, what does it mean? Are you at risk? Do you know what to do?

Ozone pollution near Earth’s surface is one of the main ingredients of summertime smog. But it not directly measurable from space, due to the abundance of ozone higher in the atmosphere, which masks the surface. Now, researchers have devised a way to use satellite measurements of the precursor gases that contribute to ozone formation to predict when and where ozone will form.

A new study shows that ozone pollution in the western United States can be increased by La Niña, a natural weather cycle at the surface of the Pacific Ocean. The finding is the first to show that the La Nina-El Nino cycles directly affects pollution.

While most people today are aware of the importance of reducing their carbon footprint, far fewer understand the harmful effects of nitrogen pollution. Yet many scientists believe that man’s disruption of the natural nitrogen cycle is a potential global tipping point and a serious threat to biodiversity.