Modelling of indoor pollutant concentrations that varies in time can be a useful tool forestimation of the strength of internal sources and sinks. Usually the modelling has beencarried out using one zone, i.e. with the assumption that the air is well mixed [1,2,3]. Thepresent paper demonstrates that the methodology may be modified to fit multizone situations.By studying the decay of a tracer gas, a correct model can be obtained for a specific volume ina building.

This study describes how the air quality in a displacement ventilated classroom can beinfluenced by the position of a contaminating person, and by the activity of a person who walksaround in the room. Tracer gas measurements have been performed in a full scale mock-up of aclassroom, with person simulators at the student's desks.The spreading of contaminants from a person seems to be strongly dependent on the positionof the person. The closer the contaminating person sits to the outlet terminal(s), the less ofhishers contaminants are spread in the room.

In this paper ventilation strategies are examined in order to improve the thermal performanceof an attached sunspace of a two-storey semi-detached house in the area of Athens Greece.The ventilation strategies examined are cross and single-sided ventilation through the verticalwindows of the sunspace. Simulations were conducted implementing multizone ventilationmodel COMIS coupled with the thermal simulation model Suncode.

This paper is concerned with heat and mass transfer through two typical staircases, The firststaircase connects the two individual floors of a two-storey building, and the other connectsthe three individual floors of a three-storey building. A series of experiments have beenperformed in order to study the buoyancy driven flow between the floors. A single tracer gasdecay technique was adopted . Temperatures at various points on each floor were constantlymonitored and air velocity measurements were also provided at some specific locations.

The goal of this project was to improve the quality of indoor air in a multistoried residentialbuilding of 81 flats built in 1960. The building is located in a heavily built urban area ofHelsinki. The building had a mechanical exhaust ventilation system without outdoor air inlets.A questionnaire was sent to occupants and a condition survey was made prior to renovation. Themain indoor climate problem was draught with a prevalence of 60 %. Other almost as commonproblems were traffic noise also during nights and dust coming from the street.

The emissions of building materials like volatile organic compounds and indoor airbornecontaminants such as environmental tobacco smoke expose occupants to hazardowsubstances. Although impacts of indoor air quality problems on human health, comfort, andproductivity are quite large, no adequate evaluation methodology exists to assess contaminantsource control techniques and building equipment systems.

Filters for gaseous contaminants which are used inside HVAC systems are characterised by means of rated air flow rate, air motion resistance, trend of the mass efficiency versus time and holding capacity of the considered gas. The determination of the characteristics cannot do without the use of experimental activities, even though many aspects seem to be foreseeable through calculation models based on general laws. A test rig for granular media which uses toluene in small concentrations in the air is presented here.

The Finnish Society of Indoor Air Quality and Climate has prepared a proposal for the classification of the cleanliness of new ventilation systems and components. The document supplements the classifications of indoor climate, construction cleanliness and material emissions published in 1995. The classification of the cleanliness of the ventilation systems consists of two parts: a classification of the cleanliness of ventilation components and a guideline for the design and construction of clean ventilation systems. The proposal will undergo an open review during next winter.

Good airtightness of a building can be achieved by the incorporation of an inner sealing layerfor the exterior walls and roofs in the form of a plastic film, which also serves as a vapourbarrier. However, if it is not wished to use plastic film as an inner sealing layer, thenairtightness must be effected through the use of other materials or in some other way. Thisproject has been concerned with investigation of a number of alternatives.

The Swedish Parliament decided 1991 that ventilation systems in all non-industrial buildingsshould be regularly inspected in intervals from 2 to 9 years, shortest for schools, hospitals etcand longest for natural ventilated flats. The systems are checked to fulfil the requirementsgiven when installed.The goals of the evaluation were to give estimated rates for how many systems that wereapproved at the end of 1997 and the cause of the faults that made the system either not to beapproved or to be remedied before next inspection.The evaluation was made in three steps:1.