passive sampling

Ventilation is critical in interpreting indoor air quality (IAQ), yet few IAQ assessments report ventilation rates; even when they do, the measurement method is often not fully described. Most ventilation assessments use a tracer gas test (TGT) to measure total air change rate. In a TGT, the indoor air is marked with an easily identifiable gas (tracer) so that the air change rate can be inferred by monitoring the tracer’s injection rate and concentration.

Ventilation is critical in interpreting indoor air quality (IAQ), yet few IAQ assessments report ventilation rates; even when they do, the measurement method is often not fully described. Most ventilation assessments use a tracer gas test (TGT) to measure total air change rate. In a TGT, the indoor air is marked with an easily identifiable gas (tracer) so that the air exchange rate can be inferred by monitoring the tracer’s injection rate and concentration.

The purpose of this investigation is to know the present status of indoor air chemical pollution byVOCs in Japanese houses. The concentrations of formaldehyde, toluene, xylene, ethyl-benzene,styrene and acetaldehyde were measured in ten thousand built houses from 2000 to 2005. And thefollowing results were obtained. In 2000, the indoor concentrations of formaldehyde exceeded theguideline established by the Ministry of Health, Labor and Welfare of Japanese Government at thepercentage of 27%. And In the case of toluene the percentage was 12 %.

The purpose of this investigation is to know the long term characteristics of VOC concentrations inhouses built before the building code in 2003 and to know the need of the countermeasures in thehouses were already built for example the improvement of the living habit, ventilation and buildingmaterials. The concentrations of VOCs were measured in these houses from 2000 to 2005. The resultsshowed that the concentration of formaldehyde decreased in the first year. After that the decline of theconcentration became invisible and the concentration changed only with the temperature.

This report details the development and field testing of a passive sampler system to collect gaseous and particulate contaminants in indoor air and the evaluation of the collected materials for biological effects using a simple bioassay system. The passive sampler-biossay system is a cost-effective objective method for determining indoor air quality.

The results of exposure chamber and field validation tests of NO2 diffusion tubes are reported. In an exposure chamber about 50 test runs at various relative humidities were performed. The field validation consisted of comparisons between tubes and a chemiluminescence monitor in 9 homes during several days in kitchen, living room, bedroom and outdoors. The results indicate a dependency on relative humidity, while the often quoted accuracy of 10% for the diffusion tubes might be too optimistic for the use of the tubes in homes.