During the past 10 years the U.S. Environmental Protection Agency (EPA) has pursued a national strategy to address radon remediation in buildings to meet its goals of radon risk reduction. Initially the approach developed and demonstrated remediation methods and techniques in existing residences with specific attention to the effect of regional climate variations and the differences in housing construction. A number of studies and demonstrations were undertaken to accurately characterize and evaluate the effectiveness of several remediation methods and techniques.

A new mechanical ventilation system which continuously controlled the indoor-outdoor pressure difference was installed in six houses, where the long-term radon levels ranged from 670 to 3 080 Bq/m³. When the new system had operated for several months, the indoor radon levels decreased to levels from 120 to 600 Bq/m³ , the effective dose reductions being from 40 % to 88 %.

A computational sensitivity analysis was conducted to identify the conditions under which residential active soil depressurization (ASD) systems for indoor radon reduction might most likely exacerbate or create back-drafting of natural-draft combustion appliances. Parameters varied included: house size; normalized leakage area; exhaust rate of exhaust appliances other than the ASD system; and the amount of house air exhausted by the ASD system.

A buoyancy-capture principle is firstly revisited as the most important fluid dynamics mechanism in kitchen range hoods. A recent new derivation of the capture efficiency of a kitchen range hood, which eliminates the inconsistencies and inadequacies of existing derivations, shows that the capture efficiency equals the ratio of capture flow rate to total plume flow rate in a confined space. The result is applied here, together with the buoyancy-capture principle, to derive a simple formula for determining capture efficiency.

This project dealt with developing the method of using activated carbon cloth as a sampler for measuring volatile organic compounds (VOC's) in air. Strips of carbon cloth mounted in slide holders were tested as diffusive samplers. These were exposed to known concentrations of standard chemicals in test chambers. The adsorbed chemicals were extracted with sol vents and analyzed. The tests showed that relative humidity has some effect on adsorption, and carbon cloths from different manufacturers showed some variation in their performance.

This report reviews research into the release of volatile organic compounds (VOCs) from paints and coatings from two perspectives: (a) drying and film formation, and (b) voc emission into indoor air. The former has been investigated by the paint industry for some decades, especially in relation to understanding drying mechanisms to assist product formulation and development. The latter is of more recent interest and is directed to predicting and controlling the impact of VOC emissions from paints and coatings on indoor air quality.