Within the ventilation principle of buildings, the outdoor air is considered as a source of fresh, "clean" air. Outdoor air quality monitoring by environmental agencies, academic research projects and a broad range of citizen science projects show that this is not always the case. Although the outdoor air quality in our cities already improved, the concentrations of certain pollutants, especially particulate matter and peak pollutions of ozone (and its precursors nitrogen oxides and volatile organic compounds), remain problematic. Ventilation systems may play a role in the introduction of these outdoor air pollutants into the indoor air, with potential adverse effects on the indoor air quality and the health of residents. The filters that are present in certain mechanical ventilation systems are primarily present to protect the system and its components against fouling, but have the potential to improve the quality of the supplied air.
In the context of indoor air quality, the aim of this project is to investigate: what role do mechanical ventilation systems play in the penetration of outdoor air pollutants? | to what extent is conventional air filtration sufficient? | what is the effectiveness and added value of advanced filtration and electrostatic precipitation as an innovative technique?
These research questions will be answered from a bottom-up research approach, including in-laboratory experiments on filters as a first step. The novelty of our research approach lies in the fact that: the measurements are carried out with the real-life pollutant load of the Brussels outdoor air, the filtration efficiency for particulate matter is considered in a measuring range of 10nm-10µm and is based on number concentrations, the filtration efficiency is monitored in function of time and the collection and penetration of chemical pollutants (O3, NOX and VOC) is also considered.
This paper presents the first results of the in-laboratory measurement part. For this part, a test setup consisting of twelve parallel test lines equipped with either one or two different air filters/ -cleaning devices in cascade was installed in our Brussels-based laboratory. The selected filters allow a comparison between different filter classes (G3,G4,F7,F9,H10), or combinations of them, and also of different types within the same class (wireframe, folded panel, bag type). Furthermore, two filters containing active carbon and two electrostatic precipitators are included in the test setup. This paper shows time resolved data including the filter efficiency and pressure drop on the filters/devices included in the test setup. The preliminary results on filter efficiency indicate a large difference in performance between different filter types within the same filter class and point to a high performance of the electrostatic precipitators within the full measuring range.