The El Tajín archaeological site in Veracruz state, Mexico, is slowly eroding due to the accumulated effects of acid rain. A team of scientists at the University of Mexico, including chemists, engineers, and meteorologists, is working together to prevent further damage to the ancient monuments at El Tajín.

This important work includes attempts to determine the sources of the acid-causing pollution. Once these sources are found, government officials can enact laws which will reduce pollution emissions and protect the monuments from further damage. If the sources of pollution are not found, the erosion of El Tajín may continue until there’s nothing left for future generations to see.

Your Job

On December 5-6, 2002 it rained at El Tajín. It was a slow, light rainfall, a steady drizzle that occurred over several hours. Each drop of rain delivered traces of sulfuric and nitric acid to the limestone rock surfaces of ancient carvings and paintings at the ruins, dissolving a small amount of the stone and pigment. The pH of the rainwater was 4.2.

Your job is to become a meteorological detective and find the sources of the acid-causing pollution for this particular event.