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Baseline indoor air quality pollutant characterisation in five United States schools.

This paper summarizes baseline results from the U.S. Environmental Protection Agency's (EPA) school demonstration studies. Indoor pollutants of concern were formaldehyde, sum of targeted volatile organic compounds o:VOC), carbon monoxide (CO), particulate matter less than 2.5 microns (PM2.5), particulate matter less than 10 microns (PM10), and bioaerosols (bacteria, fungi, and thermophiles). The five schools presented here had no significant indoor air quality problems. Locations of these schools were distributed throughout various climate zones in the United States.

Demand controlled ventilation in schools - energetic and hygienic aspects

In this study, we investigated the indoor air quality (IAQ) in classrooms with exhaustventilation systems and in naturally ventilated classrooms. In the latter, we found peak CO2-concentrations of more than 4000 ppm. 1500 ppm was exceeded during 40 to 86% ofteaching time, dependent on class size. The windows were opened rarely in winter which ledto low mean air exchange rates of 0.20 0.23 h^-1. The operation of mechanical ventilationsystems improved IAQ considerably. Peak CO2-concentrations decreased to less than 2500ppm. 1500 ppm was exceeded for only 7 to 57% of teaching time.

Indirect evaluation of indoor environmental parameters by means of audit techniques.

Some techniques aimed at the evaluation of microclimatic parameters through the measurement of other indoor physical quantities are critically reviewed. Particularly, the appraisal of the air velocity from the predicted mean vote and the determination of air change from the decay of the C02 indoor concentration are analysed. Important warnings for the use of these methods are underlined and the limits of applicability are pointed out.

Determination of air change rates by CO monitoring of supply and exhaust air concentrations.

Describes a method for determining the air change rate in a room or a building by continuous monotoring of the CO concentration in both supply and exhaust air. By using a mass balance equation, the indoor concentration of CO can be numerically calculated for various air change rates. The value of the air change rate used in the equation that gives the best correlation between measured concentration and calculated concentration provides an estimate of the air change rate for the volume studied.

Why CO2?

Describes how carbon dioxide is metabolically produced and can therefore be associated with the presence of occupants. Also it is relatively easy and inexpensive to measure, and it is fairly stable. In principle CO2 can be used to evaluate the ventilation rate, determine the proportion of outdoor air that is blended with recirculated air and provide an indication of perceived indoor air quality.

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