carbon dioxide

Diffusion-type passive monitors were placed for a two-week period in each of 303 residences in the New Haven (Conn.) area during a 12 week sampling period January to April 1983. For each home NO2 levels were recorded outdoors, and in three ro

An account is given of what the kindergarten staff wrongly believed caused the problems and what measures they carried out in an attempt to solve them. On the spot measurements showed however what the real main cause of the problems was. Results from the comprehensive measurements of CO2 concentrations andother ventilation performance criteria in a room occupied by 12 children and 3adults are then presented.

Notes the considerable savings in heating energy that could be made if ventilation rates could be modulated so that only the requirements of the actual number of occupants was supplied. Explains how this can be done by ventilating to maintain a constant concentration of carbon dioxide. Describes carbon dioxide monitoring system based on infrared absorptiometry. Illustrates diagrammatically the layout of a cinema ventilation system which monitors carbon dioxide levels and explains its operation. Notes other buildings where the system is used.

Compares the air change rates measured using the decay method with several different tracer gases. The tracer gas measurements were conducted in atightly sealed room where constant air leakage rates, ranging from 0.05 to 1 air change per hour could be maintained using an exhaust fan. The tracer gases investigated were CH4, CO, CO2, N2O and SF6. The agreement between tracer gas measurements and measured flow rates of the exhaust fan was very good for CH4, CO and N2O.

Examines the most important sources of indoor air pollution in dwellings. These include pollutants introduced with the outside air, pollutants generated by human activity, emissions from building materials, furnishings, cleaning and polishing materials and disinfectants. Notes the importance of keeping formaldehyde and carbon dioxide down to safe levels. Discusses the consequences for the minimum room air change rate.

The amount of outdoor air supply required in rooms were no one was smoking and only body odour was pesented was investigated using a climate chamer, under clean room conditions. Ten subjects were confined in the room and five panels outside of the room stated the odour level in the sampled air from theroom when compared to clean air. Experiments were performed in four steps of 5,10, 20 and 30 CMH per person. Room temperature was either 22-23 deg C or 32-33 deg C with a relative humidity of 50-60%. The higher temperature was used to study the influence of body odour in sweat.

Shows the results of a study of the effects of turbulence upon ventilation. Controlled fluctuating air flows were directed upon openings in the side of acube simulating a building. The relationship between the turbulent characteristics of the air flow and the ventilation rate in the building modeare examined. Mean windspeed and the turbulent velocity and intensity of the air flow were measured with a thermocoupled anemometer. Resulting ventilation rates were measured by means of tracer gas decay, using CO2 as the tracer and an infra red analyser to monitor the decrease in concentration.

Within the last ten years, energy shortages, economic pressures, and changes in indoor environmental requirements have resulted in buildings that are more energy efficient but less forgiving, environmentally. These results indicate that energ

Reports on some current projects in the UK using a certain type of CO2-controlled ventilation system, the "Builiding Breathaliser". This system has been installed in lecture theatres at the University of Kent, BHS department stores and cinemas owned by Rank leisure.

Examines a new energy conservation technique based on the control of the "fresh air intake" through measurement of CO2 content in extracted air for different kinds of buildings. Assesses various techniques for measuring CO2 concentration in view to design a low cost sensor, concludes that theinfra-red absorption technique is the most suitable. Shows through computer simulation that a CO2 based ventilation system can provide a better pay-back period than an air-to-air heat exchanger.