indoor

Japan is characterized by high humidity in summer and low humidity in winter. Therefore, summer is in a climatic condition where mold is easy to grow, and in fact, mold damage is occurring. Due to improvement of the thermal insulation and airtightness of houses, the temperature in the room is maintained high even in winter, and mold damage occurs. We will introduce the research we have conducted regarding humidity environment and health problems, and discuss future subjects. The outline is as follows. 

The impact of ventilation on indoor particulate pollution is highlighted by numerous studies. The aim of the present study is to examine the influence of ventilation on the levels of particulate concentrations found in dining halls where a large number of students are accommodated. Indoor particulate sources were also quantified and their influence on the particulate concentrations was examined.

A large-scale radon survey has been carried out from 1995 to 1998 in southern Greece, in order toestimate the radon concentration in Greek dwellings and the exposure of the Greek population toradon. The design was administratively orientated. The statistical criterion for the selection ofsampling locations and the distribution of radon dosimeters was the percentage of dwellings of eachlevel of the administratively classifications in respect to the above level. This way of distributionassured that all the inhabited geographical regions were covered.

Indoor radon concentrations were determined with the use of track-etched detectors and two monitors,both for radon and one for the decay products, in various regions of Greece. Until now, 1137 dwellings have been measured. Some factors, that influence the radon concentration in dwellings, are discussed in this paper. The factors, used in this analysis, were derived from the householders answers to the relevant questions about various physical features of the dwelling. Different statistical methods were used, as the unpaired t-test and the ANOVA method.

The wind speed and wind direction affected concentration of indoor radon in seven houses, which arelocated in three region of southern Finland. In the case of houses (B - F) which are built on upperslope of a permeable esker, according to the analysis of covariance the highest concentration of indoorradon, 20 - 33% over grand mean, was observed when wind (v?0.4 m.s-1) direction was perpendicularthe esker, leading to increasing pressure of soil gas and consequently to increased radon entry andconcentration.

A data set of long-term radon measurements in about 2200 houses in southern Belgium has been collectedin an on-going national Rn survey. The spatial variation of indoor Rn concentrations is modelled byvariograms. A radon distribution map is produced using the lognormal kriging technique. A GIS is usedto digitise, process and integrate a variety of data, including geological maps, Rn concentrationsassociated with house locations and an administrative map etc. It also allows to evaluate the relationshipsbetween various spatial data sets with the goal of producing radon risk maps.

Measurements of indoor radon (222Rn) concentrations were carried out by using LR-115 II solid statenuclear track detectors (SSNTD). One hundred forty detectors were placed randomly in Patras housesfor two periods of three months exposure, from December 1996 to November 1997. The observedmean radon values compared with the standard recommended values are low, while the maximumrecorded value is found to be within the limits. The influence of seasonal variation as well thedistance from the ground on radon level were also investigated.

The aim of this study was to compare the measured and the calculated concentrations of indoorradon caused by building materials at 23 workplaces. The measured concentrations of radon wereclearly higher than the calculated radon concentrations from the building materials indicating thatthe main source of indoor radon was the soil under and around the buildings. The highest means ofcontinuously (933 Bq m-3) and integrated (169 Bq m-3) measured and calculated (from 70 to 169Bq m-3) concentrations of radon were found in hillside locations.

Indoor 222Rn concentrations are influenced by several factores which may change with time,thereby causing temporal fluctuations of radon concentrations in rooms.

This study compared the concentrations of indoor air pollutants identified from the 5 restaurantsincluding a category A (two Korean barbecue houses) during a lunch time period and a category B(one Japanese, one Chinese, and one Italian restaurants) during a dinner time period.