How much time do you think it takes before the CO2 levels in a car can reach a high levels? Not very long, according to test results made by SenseAir, a manufacturer of CO2 sensors and devices.
In a real-world study they conducted using 8 SenseAir CO2 sensors mounted inside an automobile, they found that with 4 adults in the car CO2 levels reached 1,000ppm in 1.5 minutes, and 2,500ppm in 5 minutes. 2,500ppm is considered the maximum Interestingly, they found that CO2 levels reached 6,000ppm after 22 minutes even with the fresh air ventilation turned on.
Research shows that high levels of CO2 diminish the ability to make strategic decisions. Drowsiness accounts for between 10 and 30% of all automobile accidents and high CO2 levels are known to cause drowsiness, yet many people are not be aware of the importance of continually recirculating fresh air into their automobile.
What does this mean for the average driver? Over short drives with lots of passengers or long drives with few passengers, opening a window to let in fresh air can improve the reaction time of drivers and lower the likelyhood of accidents.
Today's cars are very airtight, and very few of them use CO2-controlled ventilation. Therefore, even if you don't have a CO2 meter in your car, you should get in the habit of regularly opening a window to let in fresh air.