Discovering poor IAQ in Car Journeys with Gas Sensing Solutions

As the number of registered automobiles increases dramatically each year, the number of hours an individual spends inside the vehicle also may be surprising.

On average an individual will spend 46 minutes inside a vehicle, and during those 46 minutes indoor air quality can be at its poorest.

Have you ever stopped to wonder why on long car journeys you may suddenly feel fatigued, drowsy and ready for a nap?

Well, poor indoor air quality is definitely to blame.

A recent study by the International Conference showed that the quality of air within the vehicle can truly influence and drive overall occupant comfort.

One of the biggest indicators was the confined environment and the Carbon Dioxide (CO2) which was being released by human respiration. Due to the increased levels of CO2 a driver could suddenly begin to feel dizzy, drowsy, and have a slow speed in overall reaction while on the road.

Many additional studies go on to discuss poor indoor air quality while driving, which showed that when CO2 levels exceeded the recommended level of 1200ppm after a 10 minute period - the speed in which the driver was traveling was another key IAQ indicator. 

The International Conference report also stated, "Experimental results show that accumulated CO2 concentration exceeded the recommended threshold value of 1200ppm after 10 minutes when two passengers occupied the vehicle. Even more interesting enough, the CO2 concentration exceeded the threshold 3.33 times faster for two occupants compared to one occupant in the cabin.

In terms of speed influencing IAQ, vehicles stated to be moving at higher speed of 90km/h showed a lower accumulated concentration of CO2 when compared with lower vehicle speed. Vehicle speed of 50 km/h had recorded the shortest time taken with 9 minutes to pass 1200 ppm. Then, a car which parked under a 36.5 ⁰C on a sunny day for 3 hours will reach the cabin temperature of 49.5 ⁰C."

We decided to take this research and gain even more insight into high CO2 levels and their effects on drivers, from a study by sensor partner Gas Sensing Solutions.

GSS recently took their CO2 data logger on a road trip to discover just how levels effected an individual and the overall affects due to the IAQ.

Dr David Moodie, Technical Manager at GSS, explained, “This follows on from a trip to Asia where we used our CO2 data logger to measure CO2 gas levels on planes, trains and taxis. We were surprised that levels were the worst in taxis – peaking at an astonishing 10000 ppm on one journey – so we decided to check the levels on our own road trip in the UK.”

"Before the data logger took to the road, it was first used to test CO2 levels in a stationary car. This would show the impact on CO2 levels with a group of 4 people in a confined space. The engine was switched off and the windows kept closed to avoid any flow of fresh air inside the vehicle. The data logger showed that when the passengers got inside the car, the CO2 level was 1000 ppm. It then rocketed to almost 4000 ppm in just 15 minutes. At that stage, the atmosphere inside the cabin had become extremely stuffy and unpleasant."

"Next came the road trip. The first car journey involved two people traveling to the supermarket. The CO2 from their exhaled breath increased the concentration of CO2 in the car cabin to around 1400 ppm. Surprisingly, it only took about forty-five minutes to reach this level, which shows how quickly CO2 levels can rise. The data logger was then left in the car overnight with the windows closed. The graph taken from the data logger then displayed just how long it can take for the CO2 to disperse from a closed car, taking until around 9am the next day to drop down to nearer ambient or "normal" levels of CO2."

"The second car journey recorded four people traveling non-stop from Wales to Scotland. With four people, the level of CO2 shot up even faster, reaching 2000 ppm in about twenty minutes. This is the level where CO2 symptoms can start to cause loss of concentration, headaches and sleepiness for example. Fortunately, they opened the windows to bring in fresh air from outside, which reduced the CO2 to more acceptable, ambient levels within an hour."

Dr David Moodie, added, “Our real-world data logger measurements show how CO2 levels can rapidly build up in an enclosed space with several occupants – and in a relatively short space of time too.  The results on both journeys exceeded The World Health Organization* guideline that CO2 levels should be below 1000 ppm.” 

CO2 Sensing Technologies

The data logger that was used to gain these results from the study, had at the heart a low power, ambient air, CozIR®-A sensor.

The CozIR sensor is an incredibly popular sensor using very low power consumption, high accuracy, and LED technology. By using this sensing mechanism at the heart of the data logger the team at GSS was able to record and log clear and concise data on IAQ in vehicles, over a 2 week span without needing to charge!

 

GSS CozIR®-A sensor

In conclusion, much like the evidence that surfaced from Gas Sensing Solutions and the International Conference, the results depict that individuals during car journeys could reach high concentrations of CO2 higher than safety values or prescribed standards, especially when the automobile is in full passenger capacity.

An interesting added insight was that during faster travel speed, there was enough air flow rate to prevent high concentrations of CO2 and even bring the concentrations back to normal indoor air levels.

Overall, in-vehicle transport does bring along higher than recommended CO2 levels, which could be effecting your overall focus, and ability to drive safely.

Always remember that the quality of air can be controlled by proper ventilation, circulation, speed and passenger count during your travels. 

For more information on indoor air quality applications and research, visit us

Resources:

https://www.sleepfoundation.org/sleep-topics/drowsy-driving

https://www.engr.ucr.edu/~heejung/publications/2013-CO2-model.pdf

https://www.tandfonline.com/doi/full/10.1080/10962247.2016.1268983

https://www.americanasafety.com/associates/docs/publications/The%20Drowsy%20Driving%20Off%20S

For more information on Gas Sensing Solutions, visit their website, Here. 


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