Red sky at night, sailors’ delight.
Red sky at morning, sailors take warning.
Volcano in Indonesia, Turner sunsets for years.
OK, I made that last part up. But there really is a connection between volcanoes and sunsets half a world away.
Writes Sindya Bhanoo at the NY Times, “Sunsets painted by the great masters are now providing a type of information their creators could never have imagined: important clues about air pollution.
“Polluted skies result in redder sunsets, and artists captured this redness on the canvas, said Andreas Kazantzidis, an atmospheric physicist at the University of Patras in Greece who was involved in the research.
“He and his colleagues analyzed hundreds of high-quality digital photographs of paintings done between 1500 and 2000. The period included more than 50 large volcanic eruptions around the globe.
“In each painting, they looked at the red-to-green ratio along the horizon of each sunset to estimate the amount of aerosols in the atmosphere at the time.
“When the Tambora volcano in Indonesia erupted in 1815, ash and gas spewed into the atmosphere, producing bright red and orange sunsets in Europe for several years. This is evident in the paintings of the British master J. M. W. Turner.” More.
At the NY Times, an 1829 landscape by J. M. W. Turner that researchers analyzed for its sunset. 
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