Abstract
In order to determine the factors of origin of Sick House Syndrome (SHS), data of indoor air quality in the sick houses and field survey were collected and carried out respectively, over three summer seasons from 2000 to 2002, from 35 houses where occupants are suspected of suffering from the so-called Multiple Chemical Sensitivity (MCS) and SHS, in the Miyagi prefecture of Japan. This survey consisted of the measurements of indoor air pollutants (the concentration of formaldehyde and volatile organic compounds (VOC)), air tightness and ventilation rate, together with questionnaire regarding environmental conditions, subjective symptoms and lifestyle. Medical examination was also conducted to residents having heavy symptoms. In addition, 15 houses out of 35 houses were investigated continuously for another two or three years.
As the results, the average values of formaldehyde concentration and TVOC of the investigated rooms from this study are 0.12 ppm and 1557 μg/m3, respectively.
The formaldehyde concentration in over 71% of rooms exceeds the guideline from the Ministry of Health, Labour and Welfare of Japan. While the VOC concentrations have been reducing, the formaldehyde concentration has hardly changed. The most frequently described symptoms are mucosal and respiratory symptoms (such as eye irritation, sore throat, cough). In addition, it is revealed that many patients are found having allergic diseases. The relationships between the measurement results of indoor chemical substance concentrations and the symptoms obtained from questionnaire, suggest that the symptoms become serious not only in the houses with higher concentration of TVOC, but also in the houses with lower concentration.
