During the black death epidemic (1349–1353), atmospheric lead concentration collapsed as mining ceased. This is the result of a study by Alexander More, Nicole Spaulding, Pascal Bohleber, Michael Handley, Helene Hoffman, Elena Korotkikh, Andrei Kurbatov, Christopher Loveluck, Sharon Sneed, Michael McCormick, and Paul A. Mayevski on lead levels in an Alpine glacier. They write that
[c]ontrary to widespread assumptions, … resolution analyses of an Alpine glacier reveal that true historical minimum natural levels of lead in the atmosphere occurred only once in the last ~2000 years. During the Black Death pandemic, demographic and economic collapse interrupted metal production and atmospheric lead dropped to undetectable levels.