air quality

Air-to-air heat exchangers were evaluated as a method of maintaining indoor contaminant concentration levels below acceptable levels. A mathematical simulation of air infiltration and indoor contaminant generation was used todetermine the distribution of contaminant concentrations at various average intervals including hourly and yearly. Both spot generation such as from unvented combustion, and diffuse sources, such as from materials, were considered for four contaminants, nitrogen dioxide, carbon monoxide, carbon dioxide and formaldehyde.

In this paper it is our intention to consider that ventilation is the circulation or passage of an air supply through an enclosure resulting in the displacement of some or all of the air contained in that enclosure by thesupply air. Depending on the character and condition of the supply air it can dilute or change the quality of the air in an enclosure as well as alter its temperature and humidity. A mathematical analysis of the ventilation process appears later in this paper.

Reviews some of the results of the project "The requirement-adapted ventilation system", which is part of an extensive research project "Indoor air quality and ventilation requirements" begun in Finland in 1983. Deals with the results of field measurements in which the relationship between CO2, particles and combustible gases in various buildings were measured and analysed. Also presents results of tests with an air quality-controlled ventilation system in one building.

An analysis of ventilation necessary to maintain air quality in an above-ground fallout shelter was done, making use of theoretical models, and generalizing the results to fit measurements on actual shelter data. Results show that, at most, boundary surface heat loss serves as a safety factor for ventilation systems, and thus ventilation systems should be designed to remove the entire thermal load generated within the shelter. This, when considered in addition to weather and load expectations, establishes an upper limit on ventilation equipment size.

Describes case studies of two sick Canadian buildings. The first illustrates a comprehensive programme of measuring air quality, ventilation and thermal conditions as well as monitoring the performance of the heating, ventilating and air conditioning systems. The second illustrates use of a standard survey questionnaire with back-up field monitoring of environmental parameters. In the first building the ventilation system was found to be malfunctioning. In the second building the humidity was very low.

Presents four short articles treating aspects of building ventilation: 1) Achieving a balance - the work of the AIC, 2) House full of horrors - indoor air pollution and progress in eradicating hazards, 3) Letting off steam - test houses with ventilation system for condensation control, and 4) High and dry - condensation in the roof, eaves to eaves ridge ventilation.

Tests were performed in 3 homes for 1) carbon monoxide, 2) nitrogen dioxide, 3) nitric oxide, 4) total hydrocarbons and 5) formaldehyde. Total particulate matter, by a numerical counting method, was also measured in Homes 1 and 2.

Discusses sources of nitrogen dioxide in indoor air in houses in the Netherlands. Measurements were made in a random sample of about 300 houses with a geiser in Enschede and Arnhem. A second sample of 326 houses in Ede were measured a year later. The Dutch outdoor standard for concentrations of nitrogen dioxide was regularly exceeded indoors.

The influence of indoor nitrogen dioxide exposure on respiratory symptoms of school children was investigated in a case-control study. The election method used was useful in obtaining symptomatic children, but insufficient indefining cases and controls without additional information. No relationship between indoor NO2 and respiratory symptoms was found. Bias may have been present, especially because of the high mobility of the study population. Attempts to estimate historical exposure were inaccurate.