Maps, compasses, astrolabes, and calipers are among the early tools used by ocean navigators. In the modern era, these tools have been largely replaced by electronic and technological equivalents. Despite these early beginnings, it would take many centuries before global navigation at sea became possible.
Radon for Children. Harmful Effects of Radon. Radon is the second leading cause of lung cancer (diagram to the right) and a serious public health concern. The primary adverse health effect associated with chronic exposure to radon is lung cancer (typically bronchogenic): -squamous cell carcinoma. -small cell carcinoma.
Radon is a naturally occurring radioactive gas that can cause lung cancer. You canât see or smell radon. Testing is the only way to know your level of exposure. Radon can have a big impact on indoor air quality.