Professor Bergin solves mystery behind Taj Mahal

Photo courtesy of Michael Bergin

One doesn’t have to have gone to India to know that air pollution is rife, especially in densely populated areas. Even the Taj Mahal, often listed as one of the Seven New Wonders of the World and a popular tourist attraction, is not immune to the insidious cloud of smog that stifles Agra and many other cities in India.

Over the years, a layer of soot has collected on the Taj Mahal’s exterior, but it wasn’t until Dr. Michael Bergin noticed the peculiar brownish tint in contrast to the white exterior during the Taj Mahal’s painstaking cleaning treatment that he decided to get to the root of the problem and figure out why.

“I asked what was going on, and they said they were cleaning the Taj Mahal. And then I asked more questions and they said ‘Oh, yeah, you have to clean it every five to ten years.’ So pretty quickly, I found out what it might be, but then the question of really proving it was much more difficult.”

So a new question developed: where did these particles come from?

Previous theories suggested that gases like sulfur dioxide caused the discoloration, or that it was caused by fog particles that were potentially very reactive.

Bergin commented, “Although it must have something to do with air pollution, there wasn’t really a solid research paper done on it.”

Bergin studies air quality and its influence on human health and climate – and in particular, the small, human-made particles floating around in the air such as those generated from fossil fuel combustion and coal burning. After collecting particulate matter samples from the Taj Mahal’s surface and analyzing these particles closely, he found that the samples largely consisted of black carbon, light-absorbing brown carbon and dust. These carbon particles are generated from combustion, of which the likely source is burning trash, cow dung and other biomass as fuel.

Bergin’s findings gained significance in the public and in the context of scientific realism.

“A lot of us do research at a place like Georgia Tech. All the professors are great researchers, and we all do, for the most part, very fundamental research, and we write journal papers,” Bergin commented. “After a while, we start – or at least I started – to wonder what real impact my work had, because I write very technical papers, and they appear in these journals, and other scientists read them. But I started to wonder what the true impact was on the world and on the public. One thing about this is that it’s really exciting to see research that the public is interested in.”

For Bergin, this project was not only a perfect application of his research, but it also had a huge impact on the health policy in Agra.

“They’re putting some very strict standards now on emission. The wild thing is – and I don’t know how this whole cascade went – it’s very quickly worked it’s way into public policy.”