The South Korean Ministry of the Environment has revised the laws relating to the management of interior air quality for multiple use facilities, and recommends maintaining carbon dioxide (CO2) concentration in passenger vehicles below 1000 ppm during operation in urban areas of large cities. However, the interior CO2 concentration of passenger vehicles can rapidly increase and exceed 5000 ppm within 30 min, as observed when two passengers are traveling in urban areas of the South Korean city of Jeonju with the air conditioner blower turned off and the actuator mode set to internal circulation mode. With four passengers, CO2 concentration can reach up to 6000 ppm within 10 min. To counter this, when the actuator is set to external mode, CO2 concentration can be maintained below 1000 ppm, even after a long period of running time. As part of the air conditioning system, alkali-treated activated carbon fiber filters are considered to be far superior to the commercial non-woven filters or combination filters currently commonly in use.

Abstract
 1. Introduction
 2. Experimental
  2.1. Experimental vehicles and measurement devices
  2.2. Experiment method
 3. Results and Discussion
  3.1. Change of CO2 concentration in the passenger vehicles between morning (AM) and afternoon(PM)
  3.2. CO2 concentration change in the passenger vehicle according to actuator and blower operation
  3.3. CO2 concentration change in the passenger vehicle according to window opening and closing
  3.4. CO2 concentration change in the passenger vehicle according to the number of passengers
  3.5. CO2 concentration change in the passenger vehicle according to vehicle type
  3.6. CO2 concentration change in the passenger vehicle according to area
  3.7. CO2 concentration change in the passenger vehicle according to different air cleaning filters
 4. Conclusions
 References

• Hong Gun Kim(Institute of Carbon Technology, Jeonju University)
• Yunhua Yu(State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology)
• Xiaoping Yang(State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology)
• Seung Kon Ryu(Institute of Carbon Technology, Jeonju University)