In Monet’s impressionist paintings, that dreamy haze is air pollution, study says

Then, he writes in translated letters shared by the Tate art museum, gradually fires were lit, and smoke and a haze of industrial pollution returned to the skies. His work continued.

A new study, published Tuesday in the Proceedings of the National Academy of Sciences, analyzed changes in style and color in nearly 100 paintings by Monet and Joseph Mallord William (J.M.W.) Turner, who are known for their impressionistic art and lived during Western Europe’s Industrial Revolution in the 18th and 19th centuries. The study found that over time, as industrial air pollution increased throughout Turner’s and Monet’s careers, skies in their paintings became hazier, too.

“Impressionistic painters are known to be exquisitely sensitive to changes in light and changes in the environment,” said atmospheric scientist Anna Lea Albright, lead author of the study. “It makes sense that they would be very sensitive to not only kind of natural changes in the environment, but also man-made changes.”

The early Industrial Revolution transformed lives and skies of London and Paris, the painters’ hometowns, in unprecedented ways. Coal-burning factories increased employment opportunities but obscured the atmosphere with harmful pollutants, such as sulfur dioxide.

Much of the change is apparent in the United Kingdom, which emitted nearly half of global sulfur dioxide emissions from 1800 to 1850; London accounted for around 10 percent of the U.K.’s emissions. Paris industrialized slower but still saw noticeable increases in sulfur dioxide in the atmosphere after 1850.

Air pollutants can heavily alter the appearance of landscapes in ways visible to the naked eye. Aerosols can both absorb and scatter radiation from the sun. Scattering radiation decreases the contrast between distinct objects, making them blend in more. Aerosols also scatter visible light of all wavelengths, leading to whiter hues and more intense light during the daytime.

Turner, one of Britain’s most prolific painters, witnessed the dramatic developments in his lifetime firsthand — he was born in the age of sail in 1775 and died in the age of steam and coal in 1851.

In one of his most famous works, “Rain, Steam and Speed — The Great Western Railway,” he paints a train, at the time the latest engineering marvel that allowed people to travel at unprecedented speeds, about to run over a hare, Britain’s fastest land mammal. Details in the painting, however, could almost be difficult to discern — haze and mist obscure much of the painting, an underline of the growing air pollution.

The haziness in this painting was not a fluke or one-off incident, according to the study. The team examined 60 paintings by Turner from 1796 to 1850 and 38 paintings by Monet from 1864 to 1901. Using a mathematical model, they looked at how sharp the outlines of objects were compared with the background; less contrast meant hazier conditions. They also looked at the intensity of the haze by measuring the level of whiteness; whiter hues generally indicated more intense haze.

Researchers found that around 61 percent of the contrast changes in the paintings largely tracked with increasing sulfur dioxide concentrations during that time period. (They also found a trend in whiter hues, but they put less emphasis on these results as pigments in the paintings themselves could have faded over time.)

The visual transformations are stark.

In Turner’s “Apullia in Search of Appullus,” which he painted in 1814, sharper edges and a clear sky are easily discernible. In “Rain, Steam and Speed — The Great Western Railway,” painted 30 years later, hazy skies dominate. During that time, sulfur dioxide emissions more than doubled.

The beginning of Monet’s career also differs from its end. His “Sainte-Adresse” in 1867 heavily contrasts with his Houses of Parliament series that began around 1899, when he spent time on and off in London for several months.

The team also assessed visibility, the distance at which an object can be clearly seen, and found visibility in Turner’s clear-sky and cloudy paintings before 1830 averaged about 25 kilometers but decreased to 10 kilometers after 1830. In several of Monet’s Charing Cross Bridge paintings, the farthest visible object was estimated to be about 1 kilometer away.

“Impressionism is often contrasted with realism, but our results highlight that Turner and Monet’s impressionistic works also capture a certain reality,” said co-author Peter Huybers, a climate scientist and professor at Harvard University. “Specifically, Turner and Monet seem to have realistically shown how sunlight filters through smoke and clouds.”

Perhaps, some could argue, Turner’s and Monet’s painting style just changed over the decades, giving rise to what we now call impressionistic art. But the researchers also analyzed the contrast and intensity in another 18 paintings from four other impressionist artists (James Whistler, Gustave Caillebotte, Camille Pissarro and Berthe Morisot) in London and Paris. They found the same results: Visibility in the paintings decreased as outside air pollution increased.

“When different artists are exposed to similar environmental conditions, then they paint in more similar ways,” said Albright, based at École Normale Supérieure in Paris, “even if that’s happening in different points of history.”

In its summary, the study also rejected a possible theory that Turner’s and Monet’s eyesight worsened as they aged, which could have affected their ability to paint a clear landscape. But Turner painted objects in clear detail in the foreground of paintings while successfully blurring those in the background, Albright said. Monet also didn’t develop cataracts until decades after he started his impressionistic paintings.

Ophthalmologists, the authors said in an interview, have also addressed the artists’ vision. Michael Marmor, an ophthalmology professor at Stanford, has said: “Monet was not myopic; Turner did not have cataracts.”

Additionally, Monet’s letters to his wife while living in London provide compelling evidence that he was acutely aware of the environmental changes around him. In some letters, he even laments the absence of the new industries to spark his creativity: “Everything is as if dead, no train, no smoke or boat, nothing to excite the verve a bit.”

Art historian James Rubin, who was not involved in the research, said the study was fascinating for its analysis of pigments and the progression of blurriness.

“The study … provides an empirical basis for what art historians have observed,” said Rubin, who is a professor emeritus of art history at Stony Brook University, part of the State University of New York. “These artists were certainly concerned with and were in a period of atmospheric change.”

Rubin added that both artists drew inspiration from surrounding environmental changes but certainly from different perspectives. He sums it up: Turner was generally anti-modern. Monet was ready to celebrate modernity, which to him signaled change.

For instance, Rubin said it is now generally understood that “Rain, Steam and Speed — The Great Western Railway” is not a celebration of a new technology.

“Anyone who thinks about the look of the train can see that it’s nothing but a furnace on wheels,” he said. “Many people feared the speed at which these engines could travel — about 35 mph.”

In contrast, Monet revels in the aesthetic effects of sunlight bouncing off clouds in the polluted air and “celebrates the spectacle of modern change,” Rubin said.

Portrayals of environmental changes or meteorology in paintings are not new. Some meteorologists argue that Edvard Munch’s “The Scream” depicts polar stratospheric clouds. Some have pinpointed Vincent van Gogh’s “Moonrise” to exactly 9:08 p.m. on July 13, 1889, in Saint Rémy de Provence, France. Turner’s other paintings accurately depicted sunsets during volcanic eruptions, which appear redder due to scattering through the aerosol-laden stratosphere.

Atmospheric scientist Fred Prata, who analyzed the meteorology in Munch’s “The Scream,” said this study reinforces his view “that art and science are much more correlated than most people believe.”

Albright said this study, to her knowledge, is “the first to look at anthropogenic changes in the environment and how artists might capture that in painting on canvas” and through time.

Artists and others living at the time in London and Paris “were aware of changes in air pollution and really engaging with those changes,” Albright said. “Maybe that could be a sort of parallel to today of how society and how artists respond to these unprecedented changes that we’re experiencing,” she said.