First the author asserts that the filtration with the help of fiber means is the most widely used technique for the treatment of the particle-pollution. Then he gives a clear and general information about the particle filtration with fiber-filters with their advantages and drawbacks. In conclusion, he precises that it is difficult to forecast the life time of those filters and to know how they behave with nano particles.
The principle of displacement ventilation involves air supply and distribution in a room by upwards displacement, i.e. as direct as possible through-flow in the occupied zone in order to achieve high ventilation efficiency. In addition, air distribution by displacement generally makes it possible to supply a larger quantity of air than for conventional mixing ventilation, which requires concentrated supply at high velocity.
For that study, the constant concentration dosing method and the decay method were used to test air changes performances in an office equiped with a VAV mechanical ventilation system and in a domestic apartment with natural ventilation . The measurement results from those two tracer gas methods are compared.
In a test cell equipped with an operating table, a medical lamp and a manikin representing the surgeon, air velocity and tracer-gas concentration were automatically measured at more than 700 points. Numerical simulations were performed too for analyzing air quality in operating rooms. The results showed that the distribution of the contaminants depends strongly on the presence of obstacles like medical equipment and staff.
There is a resurgence of interest in naturally ventilated offices. Most of the time, cooling the buildings is possible with the opening of windows. Simulations with the softwere TAS were made and showed that window opening allow a sufficient day or night ventilation rate, even if wind characteristics are not favourable. The optimal size, shape and location of the window apertures to reach sufficient ventilation rates has been studied along with the impact of the wind orientation and the building degree of protection on these ventilation rates.
For that study, IAQ measurements were carried out in 3 residential Singapore dwellings. CO2 levels were higher in air-conditioned bedrooms than in naturally ventilated bedrooms. Another survey demonstrated that almost all occupants using air-conditioners while sleeping presented one or more SBS symptoms than when using natural ventilation.
How to avoid or reduce the influence of suddenly released contaminant when emergency occurs ? A 3D Full scale room with displacement and mixing ventilation system is numerically studied assuming contaminant released at certain positions in the room. IACS is adopted as an index that can be applied to determine ventilation strategy with the aim of defending indoor environment against contamination.
Investigations in six car parks were carried out. Measurements of carbon monoxide levels were made during the peak hours to compare the performance of the different types of ventilation systems : the performance is better with a combined supply and exhaust system than the exhaust only system though more energy is consumed.
For that study the measurement of parameters in the indoor environment were carried out with a simultaneous survey with questions dealing with elements of the indoor environment, health status and health problems. That study reveals a significant role for the psychological state and psychological factors of the respondents of natural ventilation when sujectively describing the indoor environment.
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