air cleaning

Worldwide, there is an increasing number of publications related to air cleaning and sales of gas phase air cleaning products. This puts a demand for verifying the influence of using air cleaning on indoor air quality, comfort, well-being and health. It is thus important to learn whether air cleaning can supplement ventilation with respect to improving air quality i.e. whether it can partly substitute the ventilation rates required by standards.

The present study aimed at assessing six commercially-available in-duct air cleaning devices which are designed to be mounted in the central ventilation system of offices or commercial buildings. The selected devices use different air cleaning technologies: mechanical filtration, electrostatic precipitation, gas filtration, ionisation / cold plasma, photocatalytic oxidation (PCO) and catalysis under UV light.

The deposition rates of particles in a town-house with a forced air circulation and in-duct filters have been calculated for that study. It appears that the use of central forced-air fan along with in-duct filters allows the reduction of particle concentration. And it is more effective than reducing ventilation by closing windows or making homes more insulated.

This paper gives the main results of a thesis whose main objective was the comparison of numerical and experimental values of indoor air quality. The tests were carried out at the CSTB . That thesis has permitted to propose an index for the appreciation of the efficiency of the elimination of pollutants.

Ultraviolet germicidal irradiation (UVGI) systems are used to disinfect air, they consist in mounting shielded UVGI lamps at high level in an upper room zone, and the natural convection currents that occur in a room space carry airborne microorganisms through the UV field. This study demonstrates that the effectiveness of those systems is dependant on both the ventilation regime and the in-room air mixing.

Electret media or "charged" media are electrostatically charged materials that attract, like magnets do, microscopic charged or uncharged particulates. Those media are not the same in structure, stability, distribution of charge and size of their internal electric fields. Charge and structure together determine an electret media performance. In this paper the results of different filter media put to the tests are presented.

An experiment was carried out to determine the effect of photocatalytic air cleaning on perceivedair quality. Thirty-eight subjects assessed the air quality in a low-polluting, 108 m3 office, with pollution sources either present or absent behind a partition. The pollution sources were carpet, linoleum and chipboard. The office was ventilated with outdoor air at 0.6, 2.5, and 6 h-1. The air temperature was 22C and the relative humidity 40%.

Electrostatic air cleaners (precipitators) were tested in four classrooms during ordinarylessons for four weeks. Airborne dust in the classrooms was collected on filters using two different kinds of samplers: IOM-sampler and a new kind of ionizing sampler. The amount of collected dust was evaluated by visual inspection (filter blackening) and the content of cat allergen was measured using an amplified ELISA assay. It was found that the filter blackening was 64% lower when the air cleaners were active than when they where inactive (p

There are many schoolchildren who have a minor chemical sensitivity and cannot go toschool just because of the activities taken place such as arts & craft, waxing the floor or justopening the textbook. The solution for those children to go school is to protect them fromthose chemicals. However a renovation to make the whole classroom into a chemical freeroom is not a realistic solution for just one child not just because of its cost but also the effectto the other schoolchildren going in and out from chemical free room because of the risk ofrebound.