Abstract—It is well known that, in the absence of any fresh air, the CO2 concentration in a vehicle interior can increase above the ambient level due to the occupants’ exhalation. When the vehicle HVAC (heating ventilating and air conditioning) system is operating in recirculation (REC) mode, very little to no fresh air is ingested into the cabin interior. At the end of a commute, when the vehicle is turned off and parked, the accumulated CO2 that escapes from the vehicle interior is of importance because it is the initial conditions during the subsequent commute. During the time the vehicle is parked, CO2 diffuses from the interior to the outside through small holes and leaks in the vehicle envelope. This study considers this phenomenon under various influencing parameters, which include the wind speed outside the vehicle cabin, the air temperature inside the vehicle cabin, and the dimensions of the diffusing holes. The results indicate that the wind speed has the highest impact on the diffusion rate for a given hole size.
Index Terms—CO2 diffusion, Vehicle cabin air quality, Vehicle occupant safety.
The authors are with the International School of Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand (e-mail: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com).
Cite: Poonyapat Stitnimankarn, Thaisiri Siripoorikan, Napat Thanomkul, Prabhath De Silva, Porpin Pungetmongkol, and Joshua Staubs, "Transient CO2 Diffusion from Vehicle Cabin Micro-environment in Hot and Humid Climates," International Journal of Environmental Science and Development vol. 11, no. 5, pp. 273-277, 2020.Copyright © 2020 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).