Interzonal airflow measurement - a tool to solve pollution problems.

Knowledge of air movement within a building is often a condition for solving problems with the spread of pollution. The internal airflow paterns are mostly very complex and a survey of the airflow normally demands that measurements are carried out. Measuring equipment for defining air movement within buildings almost always uses the tracer gas technique. We have used two tracer gases and have kept a constant concentration of these in the polluted and the clean zones respectively. Thus enabling us to get a time history of the airflow between the two zanes. Concurrently, with measurements of the airflow between clean and polluted zones, we have measured the concentration of pollution components. The article describes both the results from testing the measurement method in an uninhabited test-house and the results from field measurements in a house and in a large factory building. From the results, the accuracy of the measurement method and the relationship between the calculated and actually measured pollution concentrations are discussed.