Trapped Air: Investigating CO2 Buildup

Overview

Carbon dioxide, more commonly known as CO2, is a gas that naturally occurs as a product of human respiration or as an engine byproduct. An environment with too much CO2 can cause health issues such as headaches, dizziness, reduced cognitive function, and in severe cases, a loss of consciousness. My project was meant to investigate levels of CO2 build up in three different vehicles, an EV, Gas, and Diesel. The three tests conducted evaluate the right ventilation setting to keep the healthiest levels of CO2 in the cabin of the vehicle at all times. My hypothesis proposed that the electric vehicle (EV) would maintain a lower level of CO2 throughout the tests due to the lack of a combustion engine. Combustion engines emit CO2 as a byproduct which can get into the cabin through the ventilation system combined with the CO2 from occupants breathing, it builds up much faster than it would in the EV. The tests were taken with the same air quality monitor to measure the levels of CO2 (ppm) every minute for five minutes. Each vehicle was tested with windows closed, idling, across three different conditions: (1) no ventilation; (2) air conditioning on without recirculation; (3) air conditioning on with recirculation engaged. Each test was taken over a five minute period. The results showed that the CO2 levels exceeded recommended health thresholds in all vehicles across almost every test. The use of the recirculation setting had the fastest and highest levels of CO2 accumulation tested. The air conditioning without recirculation, was the most effective out of all settings. This information is relevant to vehicle operators and passengers of today because the air quality affects all of us. We often sit in cars while idling (drive-thrus, school pick up, etc) for periods of five minutes or more without thinking about the side effects that could come with it. Many cars default to using the recirculation setting when the AC is on high, without the operator understanding its function.

Competition history

• CSEF 2026 Earth & Environmental Sciences (Track 2) (Junior Division) · Entry J-09-05

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