Which gas is often analyzed in forensic arson cases?

In forensic arson cases, carbon monoxide is often analyzed because it is a common product of incomplete combustion, which occurs when a substance burns without enough oxygen. When materials such as wood, plastics, or other organic materials are ignited, they can produce carbon monoxide along with various other gases. The presence of carbon monoxide can indicate that a fire has occurred and can provide clues about the combustion process involved.

Additionally, analyzing carbon monoxide helps forensic experts determine the conditions of the fire, such as the availability of oxygen and the nature of the materials involved. High levels of carbon monoxide at a fire scene can lead investigators to conclude that a fire was intentionally set or that it developed in a manner that restricted airflow, further aiding in the investigation.

In contrast, while other gases such as oxygen, carbon dioxide, and nitrogen play roles in fire dynamics, they are not as specifically indicative of arson as carbon monoxide. Oxygen is critical for combustion but is not typically analyzed as a product of fire. Carbon dioxide can be present in many combustion scenarios but does not specifically indicate criminal activity. Nitrogen is inert and generally does not participate in combustion processes. Therefore, carbon monoxide is the gas most pertinent to forensic analyses in arson investigations.