What is the main purpose of a smoke detector?

The main purpose of a smoke detector is to detect the presence of smoke and fire. Smoke detectors are critical components of fire safety systems, designed to identify the early signs of a fire before it escalates, thereby providing timely warnings to occupants. When smoke is present, the sensor within the detector is activated, triggering an alarm that alerts people in the vicinity to evacuate or take necessary actions to ensure their safety. Early detection plays a crucial role in reducing the risk of fatalities and property damage during a fire incident.

The other options do not align with the primary function of a smoke detector. For example, while unauthorized access, air quality measurement, and emergency lighting are important aspects of safety and security in buildings, they fall outside the specific capabilities of smoke detectors. They are not intended to provide security alerts, monitor air quality, or serve as a source of light in emergencies. The focus of smoke detectors is solely on detecting smoke, which is a critical indicator of fire presence.