Development of methods for subjective evaluation of indoor air cleaning devices

Ventilation accounts for approximately 20% of the global energy use for providing an acceptable indoor environment. The requirements for ventilation in the most standards and guidelines assume acceptable quality of (clean) outdoor air. Worldwide, there is an increasing number of publications related to air cleaning and there is also an increasing sale 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. Finally, the energy impact of using air cleaning as supplement of ventilation needs to be estimated.

Based on EU and Danish ventilation standard - DS/CEN/CR 1752, the required ventilation rate is mainly determined by perceived air quality (PAQ) which is assessed by a panel of sensory subjects that are fully exposed to the air immediate after entering a room. Recently, ISO Technical Committee 142 is working on the PAQ test methods to evaluate indoor air cleaners. The method of PAQ assessment to be used in ISO standard for evaluating air cleaners will be facial exposure assessments that are easier to be implemented for evaluating air cleaners as a standard test method. In order to use the results of facial exposure test for calculating equivalent ventilation requirement to be used in the ventilation standard, studies are needed to develop the facial exposure device and correlate the results of PAQ assessed by facial exposure with that of the full exposure. This proposed R&D is to develop the device for assessment of PAQ using facial exposure and conducting experiments to find the relation between the PAQ assessments obtained from facial and full exposures. The developed facial exposure device and PAQ assessment method will be repeated by several universities in different countries to check its reliability before it is recommended to ISO.