India’s airborne pollution has always been a problem for the rapidly developing country, but now it could severely impact one of its most famous structures – the Taj Mahal. According to a study from the Georgia Institute of Technology, the Taj Mahal’s iconic marble dome and soaring minarets now require regular cleaning due to increasing levels of airborne carbon particles and dust, which have turned the white marble an unappealing shade of brown.
“Our team was able to show that the pollutants discoloring the Taj Mahal are particulate matter: carbon from burning biomass and refuse, fossil fuels, and dust – possibly from agriculture and road traffic,” said Michael Bergin, a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. “We have also been able to show how these particles could be responsible for the brownish discoloration observed.”
The Taj Mahal was built in the 1600s by Mughal emperor Shah Jahan in memory of his third wife, Mumtaz Mahal. The mausoleum’s dome stands 115 feet high, while its minarets reach 130 feet. It attracts millions of visitors each year and was made a UNESCO World Heritage Site in 1983.
However, since the 1970s, the country’s increasing industrialization has required a regular, painstaking application and removal of a clay material, in order to maintain the brightness of the marble. Air pollution had been suspected as the culprit responsible for the discoloration, but no systematic study had been done – until now.
Working with the Indian Institute of Technology in Kanpur, the Archaeological Survey of India and the University of Wisconsin’s Environmental Chemistry and Technology Program, a team from Georgia Tech used air sampling equipment to measure air particulates around the Taj Mahal. The researchers found particles of dust, brown organic carbon and black carbon in the equipment’s filters, all believed to mainly come from fuel combustion, cooking and brick-making, trash and refuse burning, and vehicle exhaust. The dust came from local agricultural activities and vehicular traffic in the area around the site.
The plan is to now identify the sources of the particles and plan control strategies, such as reducing vehicle and industrial emissions in the area. “Some of these particles are really bad for human health, so cleaning up the Taj Mahal could have a huge health benefit for people in the entire region,” said Bergin. “The health of humans and the health of the Taj Mahal are intertwined.”