Dan Jaffe, a professor at the University of Washington, Bothell.

Dan Jaffe, a professor at the University of Washington, Bothell.

Katie Campbell, KCTS9/EarthFix

Remember the warm weather we had in 2014 and 2015? University of Washington professor Dan Jaffe says that was caused by a meteorological phenomenon known as “The Blob.”

“The Blob was a region of really unusual warm water that was sitting off the coast of Washington and Oregon,” he explains.

That blob had a surprising effect: it increased air pollution across the West.

Jaffe has been measuring air pollution from the summit of Oregon’s Mount Bachelor for years. In 2014 and 2015, he noticed spikes in ozone levels—which he eventually traced back to the blob.

Here’s what happened: The blob of warm water caused warmer weather. And, when the weather is warm, ozone pollution forms from fossil fuel emissions. The blob also meant the air was unusually still, so all that ozone pollution stayed put.

Jaffe says as climate change advances and the Pacific Northwest gets warmer.

“If you want to keep your ozone level at the same level, then it means that we’re going to have to reduce our own emissions,” he says.

Ozone pollution is associated with increased heart disease, asthma, and even early mortality.