In this study, we monitored the carbon dioxide (CO2) concentration in a high-speed train passengercabin by the in-situ non-dispersive infra-red (NDIR) method in order to investigate the effects of variousfactors, such as number of passengers and the presence of tunnels on the CO2 concentration levels.We found that the CO2 concentration was strongly related with the number of passengers andcorrelated with the presence of tunnel regions. The CO2 concentration increased with increasingnumber of passengers and increasing tunnel residence time.


The indoor air quality management of the public places is gaining wide attention in Korea, because theindoor air quality of the public places are obliged to satisfy the guidelines suggested by Korean Ministryof Environment. According to this regulation, the railroad stations are regarded as public places whilethe passenger cabin of train is excluded. However, because the passengers spend more time in thepassenger cabin than in the stations, the indoor air quality management of the passenger cabin is moreimportant.

The outdoor air ventilation rate in high-rise residences employing room air conditioners

This paper reports mainly on field studies were indoor overnight CO2 levels are monitored along with outdoor ventilation rates in bedrooms where room air conditioners are employed.The results of laboratory experiments using two typical RACs (room air conditioners) are also reported and discussed.

Comparative study of the indoor air quality of naturally ventilated and air-conditioned bedrooms of residential buildings in Singapore.

For that study, IAQ measurements were carried out in 3 residential Singapore dwellings. CO2 levels were higher in air-conditioned bedrooms than in naturally ventilated bedrooms. Another survey demonstrated that almost all occupants using air-conditioners while sleeping presented one or more SBS symptoms than when using natural ventilation.

Distribution of Carbon Dioxide Produced by People in a Room : Part 1 : Laboratory study

Carbon dioxide produced by occupants can be used as a natural tracer gas for analysing air change rates in dwellings. However, a high level of concentration uniformity is necessary for tracer gas measurements. Therefore, mixing fans are usually used. The use of such fans in occupied homes is not convenient, thus the uniformity requirement may not be fulfilled. Experiments in climate chambers were carried out to simulate the distribution of CO2 under different controlled conditions, without additional mixing. Sufficient concentration uniformity was observed in all measured cases.

Distribution of Carbon Dioxide Produced by People in a Room : Part 2 - Field study

Carbon dioxide exhaled by people can be used as a tracer gas for air change measurements in homes. Good mixing of tracer gas with room air is a necessary condition to obtain accurate results. However, the use of fans in dwellings to ensure mixing is inconvenient. The natural room distribution of metabolic CO2 was simulated in laboratory experiments and verified in a field study. The results of the field measurements presented in this paper support the findings of the laboratory study, i.e. that CO2 is well mixed into the room air even though fans were not used.

Associations between classroom CO2 concentrations and student attendance in Washington and Idaho

This paper presents the results of a study that explored if higher indoor minus outdoor CO2 concentrations were associated with increased student absence. The results of multivariate analyses are presented.

Supply air CO2 control of minimum outdoor air for multiple space systems

Supply air CO2 control (SACO2) is a technique for measuring the outdoor air fraction in the supply air and controlling the outdoor air intake. It is applicable to recirculating systems serving multiple places where ventilation targets are based on outdoor airflow rate per person. SACO2 offers significant benefits : energy savings, simple maintenance, adequate ventilation and ability to measure and record performance.

Modeling of occupant-generated CO2 dynamics in naturally ventilated classrooms

This paper presents a numerical method to estimate the concentration of occupant-generated C02 for the occupancy found in elementary school classrooms with nonforced ventilation.

CO2-Based demand control ventilation. Do risks outweigh potential rewards ?

In this article, the sources of risk using DCV (demand control ventilation) are examined along with the components typically and the possible ways to minimize risk without sacrificing potential energy savings.