pollutant

There are several reports on studies of wind tunnel experiments and calculations on the response of air flow at an opening against the periodic variation of wind velocity and pressure. In these studies, the fluctuating components of natural wind velocity have been treated definitely. In this paper, theoretically derives the probability density function from a probabilistic model of wind velocity around the buildings, the consequent wind pressure, and the resulting ventilation rate and contamination concentration.

A comprehensive theoretical framework is presented, based on the use of moments of concentration histories ie multiplying concentration readings by time of reading and then integrating with regard to time. The concept can be used to characterize either the diffusion of the supplied air or a contaminant released within the room. Results are presentd from about 50 measurements demonstrating the usefulness and practical applicability of the approach for assessing air quality in ventilated buildings. Different experimental procedures have been explored and are discussed.

Presents a mathematical model of the formaldehyde concentrations in rooms containing particle boards with known emission rates of formaldehyde. Tests the model in 3 rooms in a new house. Finds agreement within +-15% between calculated and measured formaldehyde concentrations in the rooms before painting and without furniture, carpets etc. Concludes that the combined mathematical model and the analytical method may be suitable for the classification of particle boards according to their emission of formaldehyde and for predictions of formaldehyde concentrations in the indoor environment.

Indoor air quality is determined by the sources of the contaminants and the methods used to control their concentrations. To predict the quality of air, algorithms are needed to model the rates of generation, transfer and removal of contamina

Reports the results of measurement of ventilation efficiency in a full scale model of a small office with a diffuse air supply, which can be used to improve ventilation efficiency and therefore reduce air supply rates. Steady state and transient definitions of ventilation efficiency are given. Finds that ventilation efficiency depends on air flow rate and heat gain in the office. Higher air flow rates give lower pollutant concentration in the ocupied zone but also more mixing between the occupied and under-ceiling zones.

Despite having balanced mechanical ventilation, a large number of modern buildings in Sweden have unsatisfactory indoor climate. Problems include mould, irritation of the eyes, nose and throat, skin rashes, feelings of dryness, hoarseness andheadaches. To control ventilation according to requirements the right indicator variable must be selected and the system must permit the proper control in the occupied zones. Measurements of air pollutants were carried out outside and inside a mechanically ventilated office building.

Describes a field method for surveying residences for indoor air quality. The method requires 2 days of field testing for each residence - a day to perform a multipoint tracer gas study to characterize the ventilation efficiency of the various spaces in the house and to determine the overall air change rate; and a day to measure contaminant concentrations in locations selected according to the results of the tracer gas study and contaminant generation locations. Describes and discusses results obtained by this surveying procedure in 3 energy efficient residences.

The concept of age, or residence time is applicable to characterize both how the supplied air or a contaminant is spread within an enclosed space and how quickly a contaminant is removed. Discusses the application of the concept toany enclosed space with air intakes and extracts. Establishes a direct relationship between the age concept, exposure to contaminants, and equilibrium concentrations. Treats different tracer gas techniques for measuring the age distributions and derived quantities.

Completed studies indicate that emissions from indoor sources, including those from unvented gas appliances, do not cause any undesirable effects in buildings with normal ventilation rates. However, recent energy conservation measures aimed at reducing ventilation rates have increased the problem of indoor pollutant levels, and there is a need for new, more detailed data on the indoor environment. Describes a programme initiated by GRI to collect such data and to develop control techniques for indoor pollutants.

Identifies alternative methods available to control indoor air pollutant exposures. Describes the performance characteristics of ventilation systems and of air cleaning devices used in mixed modes for ventilation of occupied spaces. Reviews models for predicting effectiveness of several alternative modes, with field trial validation results cited where available. Briefly reviews previous confined-space studies as points of departure for consideration of necessary air quality, ventilation and air cleaning.