http://www.sciencemag.org/news/2019/09/top-stories-volcanic-sunsets-world-without-oil-and-how-our-hearts-evolved-endurance

This sulfur-spewing Russian volcano is turning sunsets purple

Sunrise and sunset chasers discovered something odd this summer: In rural Colorado and the rest of the Northern Hemisphere, Earth’s daily light shows were turning purple. Now, weather balloons probing the stratosphere have traced the mysterious purple light to a volcanic eruption in Russia.