Air pollution in Capital accelerating Humayun’s Tomb decay: IIT study, Pg5

Key Highlights:

• A joint study by IIT Kanpur and IIT Roorkee found that air pollution is accelerating the decay of Humayun’s Tomb in Delhi.
• The decay is caused by the formation of pollutant-rich black crusts on the monument's sandstone surfaces.
• The study, published in the International Journal of Architectural Heritage, provides evidence for preventive conservation strategies.
• Samples collected from the UNESCO World Heritage Site revealed that the black crusts are dominated by gypsum and carbon-rich particles.

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Detailed Insights:

• The black crusts form when calcium from road dust and airborne particles reacts with sulfur compounds in polluted air to create gypsum.
• Trace metals found in the crusts are indicative of urban pollution sources like vehicular traffic, construction dust, and industrial activities.
• Prevailing northwesterly and westerly winds during post-monsoon and winter months transport pollutants like SO2, NOx, PM2.5, and PM10 across Delhi.
• The research recommends periodic removal of black crusts using scientific cleaning techniques and evaluation of protective coatings.
• Continued air-quality monitoring and atmospheric modeling are suggested to assess future deterioration risks for the monument.
• The study was conducted under the supervision of a conservator from the Archaeological Survey of India (ASI).

Key Concepts Involved:

• Humayun’s Tomb: A UNESCO World Heritage Site in Delhi, India, representing early Mughal architecture.
• Gypsum: A soft sulfate mineral, often formed on monuments due to the reaction of atmospheric sulfur compounds with calcium-containing materials.
• Particulate Matter (PM2.5, PM10): Microscopic solid or liquid particles suspended in the air, contributing significantly to air pollution.
• Archaeological Survey of India (ASI): An Indian government agency responsible for archaeological research and the conservation and protection of cultural heritage.