This study presents a comparison of perceived indoor conditions in both air-conditioned and naturally ventilated buildings.

As part of a graduation research, six case studies were carried out to assess the validity of 10 often heard assumed disadvantages of natural ventilation in offices, including poor IAQ and thermal discomfort. The case studies included a methodic comparison of six buildings based on literature, interviews, field measurements and re-analysis of reports by others. Thus the preconditions for natural ventilation of office buildings and the most important design features could be determined in order to meet the performance standards as in use in the Netherlands.

A design procedure of material and hybrid ventilation systems is described. It includes a climate suitability analysis, a loop equation design method and a detailed multizone coupled thermal-airflow analysis using CONTAM97R software.

The potential for natural ventilation is the rating of the possibility to achieve a good indoor air quality by natural ventilation only. The potential for passive cooling can also be defined. These potentials depend on site and building and are based on several parameters. Example of determination in Geneva area is given.

Three portable air cleaners alone or combined with ultra-violet germicidal irradiations were tested to determine their capacity to remove airborne bacteria. Results give values of airborne bacteria removal rates.

The impact of an ozone generator air cleaner was investigated in a full scale test chamber. Test results demonstrate that, where styrene is present, air cleaners increase indoor levels of formaldehyde, oxygentaed organic compounds, ozone and nitrogen dioxide.

Experiments with an air-handler and electronic air cleaner (producing ozone) were operated in a Canadian house to analyse ozone indoor levels for different air change rates and outside ozone levels. Continuous operation of air cleaner increases indoor ozone levels by up to 9 ppb, which may push indoor ozone levels higher than outdoor guidelines figures.

A test protocol for the determination of fractional filtration efficiency of electrostatic precipitators was developed in order to determine the changes in efficiency of these appliances in real life, due to reduced corona discharge from the ionizing wires, and to define an accelerated laboratory method reproducing the real life vapor deposition process leadiong to the coating of the wires.

The performance of two gaseous air cleaners in a single test room was measured for toluene. The effectiveness is between 82 and 94%. Numerical simulations were performed with CONTAMW software to predict indoor air quality. The comparison with experimental results is good.

Sixty pubs were investigated in the UK to measure environmental tobacco smoke (ETS) concentrations in smoking and non-smoking areas. The ETS sampling equipment is described. A statistical exploitation of the results shows that the status of the zone has a big influence on its ETS level: ETS concentration in smoking areas is higher than in non-smoking areas, but ETS exposures are significant in the non-smoking parts. Results also show that the effect of the ventilation system on the ETS concentration is not significant in such pubs.