Carbon monoxide (CO) poisoning can definitively occur in a parking garage. CO is a gas that poses a serious threat in enclosed or poorly ventilated spaces. It is a byproduct of incomplete combustion, produced anytime a fuel source like gasoline or diesel is burned, such as in a vehicle engine. Because CO is colorless, odorless, and tasteless, it is impossible for a person to detect its presence without specialized equipment.
Why Carbon Monoxide Accumulates in Parking Structures
The primary source of carbon monoxide in a parking structure is the exhaust emitted by vehicles moving slowly or idling. When a car engine is running, the incomplete burning of fuel releases CO gas directly into the surrounding environment. This risk is amplified in structures like underground or multi-level garages, which are designed to be semi-enclosed or fully enclosed.
Garages rely on mechanical ventilation systems, but if these systems are inadequate, CO concentrations can quickly rise. High-traffic periods, such as rush hour, exacerbate the problem as a large volume of vehicles simultaneously produce exhaust in a confined area. Unlike open-air surface lots where natural air currents rapidly disperse the gas, the architectural design of many garages traps the gas.
When the ventilation cannot keep pace with the vehicle emissions, the gas accumulates to levels that are hazardous to human health. Modern standards require demand-controlled ventilation that activates based on CO levels. However, a failure or delay in this system can create dangerous localized buildup.
Recognizing the Signs of Exposure
Carbon monoxide poisoning occurs when the gas enters the bloodstream and binds with hemoglobin, the molecule responsible for carrying oxygen. Because CO bonds with hemoglobin about 200 to 250 times more readily than oxygen, it effectively starves the body’s tissues and organs of the necessary oxygen supply. Symptoms of mild exposure are often non-specific and easily mistaken for common ailments like the flu or simple fatigue.
Initial signs of exposure include a dull headache, dizziness, and nausea or vomiting. As the concentration of CO increases or exposure time lengthens, the symptoms become more severe and neurological. These advanced signs can involve confusion, weakness, chest pain, and difficulty breathing.
At extremely high concentrations, a person may experience loss of consciousness, seizures, or respiratory failure, which can lead to brain damage or death. Anyone experiencing these symptoms must immediately move to an area with fresh air. CO poisoning requires urgent medical attention, so emergency medical services should be called immediately, even if symptoms appear to subside after leaving the area.
Safety Protocols and Prevention Strategies
Preventing carbon monoxide exposure relies on a combination of facility design and individual user behavior. Facility managers install fixed CO monitoring systems that constantly measure the gas concentration in parts per million (ppm). These detectors are integrated with ventilation fans, allowing for demand-controlled ventilation that automatically increases airflow when CO levels rise, maintaining air quality within safe limits.
Building codes and safety standards, such as those from ASHRAE, establish the maximum allowable CO concentration to ensure the safety of occupants. For individuals, the most effective prevention strategy is to minimize the source of the gas. Vehicle operators should turn off their engines immediately upon parking and avoid idling while waiting for a space or a passenger.
Minimizing the time spent inside the structure also reduces the total dose of exposure a person might receive. It is wise to avoid prolonged activities in areas with restricted airflow, such as near entry and exit ramps where vehicles queue. These measures help ensure that mechanical systems can successfully manage ambient CO levels.