Two methods have been used for measurement of natural convection flows in a narrow vertical channel of which one wall is heated : a hot wire anemometer adapted to measurements in flows where temperature gradients exist (two hot wires with different overheat) and a method for attaining bulk flow information in boundary layer flows. Results from these two methods are compared.

Guangdong is one of the provinces that have most hot springs in China. This paper presents the results of radon measurements in hot spring hotels of Guangdong province by using NR-667A continuous radon detector. Radon concentrations were measured in hotel rooms with attached bathrooms, tap waters and outdoors air. Radon concentrations were 53.4-292.5 Bq/L in the hot spring water, and 17.2-190.9 Bq/m3 in outdoor air.

Provision of good IAQ in buildings located close to a busy road requires application of air filtration systems which are efficient for submicrometer and especially ultra fine particles, since traffic emissions are associated with particles in these size ranges. A study has been conducted in which a filtration system of an office building was designed according to measured outdoor air conditions and theoretically predicted indoor air conditions. The performance of the system was then validated by field measurements of particle concentration levels indoors and outdoors.

Interior Alaska has indoor air quality issues similar to other far northern communities associated with long cold winters and reduced ventilation rates. Moreover, geological features in the hills around Fairbanks, Alaska increase the likelihood of elevated radon levels. Over thirty percent of the tested homes in the hills around Fairbanks had radon levels > 4 pCi/L compared with a nationwide average of 7%. Active sub-slab depressurization systems tested were very effective in reducing indoor radon concentrations (average reduction of over 90% for 8 homes).

An intervention study was carried out in eleven elementary schools in Trondheim, Norway. Three schools with poor ventilation standard, four schools with carpets, and four reference schools participated. Carpets were replaced by vinyl flooring and the poor ventilation systems were upgraded. Altogether 1100 children aged twelve to thirteen years and 400 teachers were all included in the study. The baseline registration of health related symptoms was performed during January/February 1997. The questionnaires were repeated, after the interventions, in February 1998 and 1999.

Two nation-wide indoor radon surveys have been conducted in Japan. There was a significant difference between the two surveys. The first survey covered over 7000 houses using Karlsruhe passive radon detectors developed in Germany. The first survey provided relatively higher radon concentrations than expected though there are many well-ventilated wooden houses in Japan. The arithmetic mean was estimated to be 20.8 Bq m-3. In the second survey, on the other hand, it was 15.5 Bq m-3.

An innovative thermal comfort meter has been developed. It can simulate the human body evaporative losses. The sensor has been calibrated in a climatic chamber with different air temperature, velocity and humidity.

Indoor exposure to particles of outdoor origin constitutes an important exposure pathway. We conducted an intensive set of indoor particle measurements in an unoccupied house under differing operating conditions. Real-time measurements were conducted both indoors and outdoors, including PM2.5 nitrate, sulfate, and carbon. Because the time-scale of the fluctuations in outdoor particle concentrations and meteorological conditions are often similar to the time constant for building air exchange, a steady state concentration may never be reached.

Values for total dust concentration in indoor air in day-care centres, offices and schools with no reported problems are measured. These are: day-care centres 41 14 g/m3, offices 16 5 g/m3, schools 20 10 g/m3. In parallel the particle size distribution in six interval from 0.3 m - >20 m are reported. No seasonal variation in total dust concentration could be seen. Sudden increase in number of the particles in the smallest intervals are found at night for some systems when they are shut down or working on reduced speed.

The Indoor Air Quality Committee of the Boston Society of Architects was invited to evaluate a large brick school building erected in 1963 to serve 1600 students. The investigation included a written questionnaire, evaluation of air using the ASTM E981 (modified) bioassay, fungal and bacterial testing, real time monitoring of carbon dioxide, carbon monoxide, respirable particulate, total volatile organic compounds, relative humidity and temperature. The survey and testing enumerated many potential causes for poor IAQ.