indoor air quality

Hybrid ventilation represents an interesting option both to guarantee good air quality for indoor environments and to reduce the energy consumption related to the mechanical motivation of the air.

Stratum ventilation is a recently proposed air distribution system. It works by creating a layer of fresher air in the occupants' breathing zone. This is achieved by placing large supply inlets along the side-walls of the room just above the height of the occupants. Fresh air is emitted into the room and gradually loses momentum. The supply velocity is sufficiently strong to provide fresh air directly to the occupants without space mixing.

Ventilation systems are primarily designed for ensuring good indoor air quality (IAQ). However, building energy requirements tend to put demand on reducing air change rates. The assessment of the performance of ventilation systems over long periods has thus become a subject of importance. In this framework, five ventilation systems were investigated for a heating period in a single-family house using a representative occupancy and pollution schedule. This was undertaken using SIMBAD, a combined mass and heat transfer toolbox. This paper compares the different results.

In dwellings there is a desire to reduce ventilation heat loss, by reducing uncontrollable air infiltration, at the same time as providing adequate indoor air quality by controllable background ventilation. In England and Wales, the background ventilation requirements in part F of the Building Regulations at present are expressed in prescriptive terms. The adopted European Standard, EN13141-1:2004, provides a means of assessing the performance of background ventilation devices, such as trickle ventilators, and gives a standard method of measuring the equivalent area of the ventilator.

The term air conditioning not only prescribes comfort temperature and relative humidity, but also the quality of air inside the room. Indoor Air Quality (IAQ) has become a concomitant of air conditioning. The pollutants generated inside the room affect the quality of air inside the room. The major pollutants considered are occupant generated (carbon dioxide - CO2, odour), sulphur dioxide and toluene etc. The monitoring and controlling of all pollutants is cumbersome.

The present paper aims at investigating the indoor air quality in fifteen school buildings located in the greater Athens area. Experimental investigations were performed in fifteen different school classrooms and the concentration levels of various pollutants such as CO2, CO, TVOC, HCHO, and radon, were measured. Moreover, the experimental investigation included measurements of several environmental parameters such as temperature, relative humidity and air velocity inside each classroom, while ventilation was examined by estimating the air changes using the tracer gas technique.

The Austrian Radon Project (ARP) is aimed to investigate and measure systematically the indoorradon concentration in about 0.5% of all Austrian homes. With the information from this surveyareas of enhanced indoor radon concentration can be identified and people living in such areasshould be encouraged to mitigate their homes. The radon potential is introduced by normalizingthe observed radon data to a standard situation. By mapping the radon potential an overview on thegeological risk for enhanced indoor radon concentrations will be available.

Recent studies show that improving indoor air quality (IAQ) from the mediocre level prevalent in manybuildings worldwide improves the performance of office work by adults and the performance ofschoolwork by children. These results constitute a strong incentive for providing indoor air of a qualitythat is better than the minimum levels required by present standards.

A desiccant air-conditioning system has been suggested as being suitable to improve indoor air qualitydue to its superior humidity control. However, this system has the drawback of being less energyefficient, so it is typically used in conjunction with co-generation systems or solar heating systems toimprove its energy efficiency. In previous studies, we proposed a new type of desiccant air-conditioningsystem combined with a CO2 heat pump, and studied its applicability through experiments andsimplified calculations.

This study explored the reduction effect of indoor pollutants by the kinds of plant. The effect of reducingthe concentration of air contaminants by three species of plants was studied in a full-scale mock-upmodel. Aglaonema brevispathum, Pachira aquatica and Ficus benjamiana were used. Their positionsand amount were controlled. Field measurements were performed in models where the plants wereplaced and were not. The dimensions of the two models were equal.