Before 1923, the atmosphere had very little lead contamination, indicating a relatively clean environment. However, since that year, lead levels have increased significantly, posing serious risks to health and the ecosystem. Bill Bryson, in his book "A Short History of Nearly Everything," highlights this concerning trend, drawing attention to the unintended consequences of industrialization and improper use of lead in various applications.

This rise in atmospheric lead reflects broader issues related to pollution and environmental degradation over the past century. Bryson's work urges readers to recognize the implications of human activity on the planet and emphasizes the need for awareness and action to mitigate these dangers for future generations.