English

Ventilation is widely used to help maintain acceptable indoor pollutant concentrations. In this paper, the relationships between ventilation rate and indoor concentration are examined by the use of mass balance models and measured data. It is shown that the pollutant source strength and pollutant removal by processes other than ventilation can have a large impact on the indoor concentration and that maintenance of a typical ventilation rate does not ensure an acceptable indoor concentration.

Air infiltration in two well-insulated houses is being investigated to determine its effect on energy use and indoor air quality. The first paper of this series provides a general perspective on the design. This paper reports on the effect on conservation measures taken, including the installation of an air-to-air heat exchanger, on air exchange and energy use. A third paper presents pollutant measurements and modelling results.

The general principles and mechanism of how soil gas infiltrates and carries radon from the foundation bed and subsoil into buildings are discussed. The Swedish Building Research Council has funded experiments and evaluation of cost effective remedial actions. The work has concerned existing dwellings with high concentration of radon, resulting from infiltrating soil gas and/or exhalation from building materials. A review and evaluation is given of experience and results acquired up to the summer of 1984.

The paper proposes a methodology for evaluating and ranking specific alternatives for control of indoor air quality in existing buildings, based on comparative costs and benefits. The method avoids the difficulties of assigning a monetary value to a change in air quality by adjusting the air exchange rate in each alternative until equivalent indoor air quality is achieved. The difference in air exchange rates between alternatives allows calculation of energy savings, which can be compared to capital cost savings,which can be compared to capital cost using the payback period method.

As part of a comprehensive indoor air quality and infiltration field study, radon concentrations were measured in 60 houses in upstate New York using passive integrating monitors. Indoor air radon concentrations ranged from 0.2 pCi/1 to 50 pCi/1. Four houses with the highest radon levels were then extensively monitored using real-time continuous instruments for the measurement of radon, radon daughters, respirable particles, infiltration, inside-outside pressure difference, and weather parameters.

Plastic track detectors LR-115 and CR-39 were used to estimate the concentration of radon-222 and its daughter products (218Po, 214Po) in a room by recording tracks of their alpha-particles. Although the ventilation rate is the main factor th

When indoor air concentrations from indoor combustion processes are estimated, source strengths and ventilation rates are usually considered. Recent studies, conducted in the Energy Research House at Iowa State University, indicate that seve

The effectiveness of range hoods and window fans in removing indoor pollutants is considered. Tests were conducted in a two-room test space with an infiltration rate less than 0.1 hr-1 using sulphur hexafluoride as a tracer gas. Range hood te

Based on the age concept, the performance of the following three principle ventilation schemes have been monitored (supply air terminal - extract air terminal), ceiling-ceiling, ceiling-floor, floor-ceiling. All systems used only air for both heating and cooling. Contaminants with both greater, less and approximately the same density as air were released at a point source. The tests were both carried out in an empty room and with a person (heated mannekin) in the room.

The indoor air quality depends on several different factors. One is the air flow or air movements within the building and through its external walls. These flows are governed by the type of leakage openings and the pressure differences across the walls and the air terminal devices. The pressure differences are caused by wind, thermal and fan forces. Mathematical models can be used to calculate the different air flow rates. A simple example is used to demonstrate magnitude and consequences of this air leakage for two different ventilation systems.