Characterisation of filter performance in relation to outdoor air quality

Airborne particle size distribution depends on the type of source from which the particles originate - filtration efficiency in turn, is dependent on particle size. Thus, in order to optimise filtration efficiency, it is important to gain knowledge on both: the size distribution of particles in the air to be filtered and the relationship between filtration efficiency and particle size. In addition, assessment needs to be made about the expected concentration level of particles around the building envelope and its time variation. This information is necessary for selecting the most suitable type of filters for the characteristics of particles that dominate in outdoor air. The aims of this project were to: (i) establish typical scenarios in relation to outdoor air concentration and size distribution, and (ii) to assess filtration performance of tested air filters in ultra fine, submicrometer and PM2.5 size ranges.