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Air supplied by ventilation plants and air conditioning systems carries small particles whose size depends on filtration device efficiency.

Mineral, vegetal or biological particles may deposit on the inner surface of air ducts and other air conditioning equipment creating a thin layer of dust. Such dust deposit may deteriorate the quality of the air flow blown into the rooms through the booths and consequently the global indoor air quality in the building.

The role of CO2 to control the indoor air quality in buildings is based on the fact that CO2 developed by people breathing may be used as a marker for the bio-effluents produced by people. The use of CO2 for the steering of ventilation systems is only appropriate in the case that no other pollutant is more dominant for the indoor environment. For instance when a person is taking a shower in a bathroom, moisture will be the more dominant pollutant. Nevertheless the use of CO2 as marker for the indoor air quality is widely used.

For the near future the expectation of experts is that the most promising systems will be based on demand-controlled hybrid ventilation technologies. The impact of further development and the improvement of fully mechanical or fully natural ventilation systems on energy savings and indoor air quality is reaching its limits. The hybrid part of the system is of course the minimisation of the electric power of the fan by improving the fan efficiency and low pressure ducting.

Born with the energetic crisis, humidity controlled ventilation has been introduced in regions with a moderate climate as a means to fight condensation problems induced by tighter building construction and lower heating temperatures.
This paper develops the means and goals of humidity controlled ventilation in the framework of the building energy reduction.
Why have a variable airflow? 
Why chose humidity as the driving parameter? 
How does humidity controlled ventilation work? 

Recently, there has been a growing public concern over indoor air quality not only in buildings but also in vehicles. Since the vehicle is the main form of daily transportation for most people, of particular concern is the symptoms suffered by both drivers and passengers such as fatigue, headache, and eye stimulation caused by formaldehyde and volatile organic compounds (VOCs) emitted from the interior materials of newly assembled vehicles.

This VIP focuses on best practice, as well as challenges, for the conditioning of the indoor environment in passenger aircraft cabins, and their implications from a ventilation stand-point.
This article is based largely on findings from EU’s FP5 project “CabinAir”.
In early commercial jet aircraft, passenger cabins were ventilated with 100 % outside air. In more recent jet aircraft, approximately 50 % of the ventilation air is outside air and the remaining 50 % is filtered recirculated cabin air.

Ceiling fans are one of the more credible techniques to decrease the energy consumption for air conditioning and improve comfort. Historically, ceiling fans have first emerged in hot humid climates and have become more and more popular in certain parts of the world from the early decades of the last century.

Existing thermal comfort standards and methods cover mainly thermal comfort conditions under steady state conditions. Most of the thermal comfort studies have been carried out in laboratories and are based on evaluations of the heat transfer between the human beings and their environment and of the required physiological conditions for thermal comfort.