title: In-vehicle carbon dioxide concentration in commuting cars in Bangkok, Thailand.
abstract: It is known that in-vehicle carbon dioxide (CO2) concentration tends to increase due to occupant exhalation when the HVAC (heating, ventilation, and air conditioning) air is in recirculation mode. Field experiments were conducted to measure CO2concentration during typical commute in Bangkok, Thailand. The measured concentrations agreed with the concentration predicted using first-order mass balance equation, in both recirculating and outside air modes. The long-term transient decay of the concentration when the vehicle was parked and the HVAC system was turned off was also studied. This decay was found to follow Fickian diffusion process. The paper also provides useful operational details of the automotive HVAC system and fresh air ventilation exchange between cabin interior and exterior.
  
  
  
  Drivers in tropical Asian countries typically use HVAC recirculation mode in their automobiles. This behavior leads to excessive buildup of cabin CO2concentration levels. The paper describes the CO2buildup in a typical commute in Bangkok, Thailand. Auto manufacturers can potentially take measures to alleviate such high concentration levels. The paper also discusses the diffusion of CO2through the vehicle envelope, an area that has never been investigated before.
authors.affiliation: a International School of Engineering, Chulalongkorn University , Bangkok , Thailand.
authors.forename: Maytat
authors.initials: M
authors.lastname: Luangprasert
authors.affiliation: a International School of Engineering, Chulalongkorn University , Bangkok , Thailand.
authors.forename: Chainarin
authors.initials: C
authors.lastname: Vasithamrong
authors.affiliation: a International School of Engineering, Chulalongkorn University , Bangkok , Thailand.
authors.forename: Suphasit
authors.initials: S
authors.lastname: Pongratananukul
authors.affiliation: b Smart Mobility Research Centre, Department of Mechanical Engineering , Chulalongkorn University , Bangkok , Thailand.
authors.forename: Sunhapos
authors.initials: S
authors.lastname: Chantranuwathana
authors.affiliation: c Department of Electrical Engineering , Chulalongkorn University , Bangkok , Thailand.
authors.forename: Suree
authors.initials: S
authors.lastname: Pumrin
authors.affiliation: a International School of Engineering, Chulalongkorn University , Bangkok , Thailand.
authors.forename: I P D
authors.initials: IP
authors.lastname: De Silva
mesh_terms: D000389:Air Conditioning; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis* / Q000706:statistics & numerical data; D001336:Automobiles; D002245:Carbon Dioxide / Q000032:analysis*; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D013785:Thailand; D014691:Ventilation; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D002245:Carbon Dioxide