carbon dioxide

One of the most commonly used strategies to reduce the heating demand in low energy buildings is reducing the leakage level of the building envelope. Dedicated ventilation systems are then installed to compensate for the reduced air change rate in an energy efficient way. Most occupants, however, operate their ventilation system at very low flow rates. Together with the emission of bio-effluents, linked to the presence of the occupants, moisture production related to household activities is one of the most important sources of indoor air pollution in dwellings.

Air change rate is often used as an important characteristic of indoor environmental quality, which significantly impacts human health. However, easy, effective, real-time and low-cost air change rate measurements in naturally ventilated resident buildings are still a huge challenge. This paper presents a method based on the release of a stable rate of the tracer gas CO2 given off by solid CO2 (dry ice) in an insulated box.  In theory, the dry ice will sublime at a constant rate as long as there is sufficient dry ice in the box.

Carbon dioxide included in exhaled breath is often used as a tracer gas when estimation of ventilation aspect in buildings with occupants is performed. Carbon dioxide produced by occupants is the key for the estimation. JIS A 1406 and ASTM D6245-12 refer personal carbon dioxide production rate. However JIS does not take into account personal attribute like as body height and weight. On the other hand, ASTM does not take into account gender difference and based on average westerner adult data.

Demand-controlled ventilation has been proposed to improve indoor air quality and to save energy for ventilation. It is important to estimate occupancy in a building precisely in order to determine adequate ventilation airflow rates, especially when people are the major source of indoor contaminants such as in office buildings. In this paper, we investigate occupancy estimation methods using a dynamic neural network model based on carbon dioxide concentration in a space.

A pilot survey was undertaken from September 2009 to June 2011 in 310 schools and day-care centres distributed in all regions of France including overseas departments. This experimental survey was carried out as part of the preparation of the mandatory control of indoor air quality in public buildings. Three parameters were measured in 896 classrooms or child playrooms: benzene, formaldehyde and carbon dioxide (CO2). The last enables the determination of degree of air ‘stuffiness’ during children occupancy as well as the night-time air change rate.

This study copes with the problem of ventilation in existing educational environments in terms of indoor air quality (AIQ), comfort and energy consumption. In accordance with international regulations, densely occupied environments such as school classrooms need high air change rates in order to provide sufficient fresh air. Nevertheless, in Italian schools, it is rare to see mechanical ventilation systems or natural systems that are mechanically controlled. This means that it is necessary for the users to control air changes by opening or closing the windows.

The provision of good IAQ in schools is important both for the health of students and in maximising educational achievement. It is, however, common for school classrooms to be significantly under-ventilated and this can lead to high levels of CO2 and other pollutants. Natural ventilation offers the potential to improve IAQ within schools whilst, at the same time reducing running and maintenance costs. Accordingly, this article examines a natural ventilation strategy based on the use of a roof mounted split-duct Windcatcher ventilator. Here, 16 U.K.

It is widely recognised that the carbon dioxide (CO2) concentration level inside a building is a reflection of the indoor air quality in that building. In most buildings, occupants are a major source of CO2 through exhalation. It is generally accepted that the concentration of CO2 varies with location (horizontal and vertical) within an enclosed space and this can impact on the variation of indoor air quality within the space. Hence, measurement errors related to CO2 sampling strategies in a space are important as they can lead to uncertainties in the mean concentration for the space.

Limited data are available for understanding indoor environmental quality (IEQ) and the related healtheffects in schools in China.

This study aims at investigating the actual conditions of indoor environment in schools in order to obtainfundamental information for proper ventilation design for buildings. Indoor environment of two newelementary schools in Tohoku district of Japan was investigated for a week in the winter of 2005.Temperature and humidity, concentrations of carbon dioxide (CO2), ventilation airflow rates,concentrations of chemical substances, and the opening condition of the windows and doors weremeasured and recorded in the three classrooms of each school.