What should trigger the automatic operation of mechanical ventilation systems in enclosed parking garages?

The correct answer is the carbon monoxide detectors. In enclosed parking garages, the primary concern is the accumulation of harmful gases, particularly carbon monoxide (CO), which can be emitted from vehicle exhaust. When vehicles are running, they produce carbon monoxide, which is a colorless, odorless gas that can be very dangerous if allowed to build up in enclosed spaces.

Carbon monoxide detectors are designed to monitor the levels of this gas continuously. When CO levels exceed established safety thresholds, these sensors automatically trigger the mechanical ventilation system to activate, ensuring a sufficient exchange of air to dilute and remove the harmful gas from the environment. This response not only enhances safety for individuals utilizing the parking garage but also meets regulatory standards for air quality in enclosed spaces.

Temperature sensors, while useful for various HVAC functions, primarily relate to maintaining comfortable conditions rather than addressing the specific air quality concerns in a parking garage. Humidity sensors focus on moisture levels, which are not the primary issue in this context. Time-based timers do provide a method to manage ventilation systems based on predetermined schedules, but they do not respond to real-time air quality concerns, making them less effective than carbon monoxide detectors for this specific application.