Final answer:
Nitrogen is the gas in air causing decompression sickness and narcosis, with decompression sickness managed by slow ascents and sometimes hyperbaric oxygen therapy, while research is advancing diagnosis and treatment options.
Step-by-step explanation:
The gas component in air that causes decompression sickness and narcosis is nitrogen. Decompression sickness, also known as 'the bends', occurs when nitrogen bubbles form in the bloodstream and tissues due to a rapid decrease in ambient pressure as a diver ascends. Narcosis, often called 'nitrogen narcosis', happens at depth due to the increased solubility of nitrogen which affects the nervous system, leading to altered consciousness and a decline in cognitive function.
Decompression sickness (DCS) and narcosis can be managed with proper ascent rates and the use of decompression stops to allow gases to dissolve safely. In severe cases, hyperbaric oxygen therapy in decompression chambers can treat DCS. Researchers like Ingrid Eftedal are furthering our understanding of DCS through studies of white blood cell reactions, potentially leading to advanced diagnostic tests and better management of the condition.