Air filters from HVAC systems as possible source of volatile organic compounds (VOC) - laboratory and field assays

The emission of volatile organic compounds (VOC) from air filters of HVAC s ystems was to be evaluated. In a first study carbonyl compounds (14 aldehyd es and two ketones) were measured by reacting them with 2,4-dinitrophenylhy drazine (DNPH). Analysis was done by HPLC and UV detection. In laboratory e xperiments pieces of used and unused HVAC filters were incubated in test ch ambers. Filters to be investigated were taken from a tilter bank of a large HVAC system in the centre of Berlin. First results show that - among those compounds - formaldehyde and acetone were found in higher concentrations i n the test chambers filled with used filters in comparison to those with un used filters. Parallel field measurements were carried out at the prefilter and main filter banks of the two HVAC systems. Here measurements were carr ied out simultaneously before and after the filters to investigate whether those aldehydes or ketones arise from the filter material on site. Formalde hyde and acetone significantly increased in concentration after the filters of one HVAC system. In parallel experiments microorganisms were proved to be able to survive on air filters. Therefore, a possible source of formalde hyde and acetone might be microbes. (C) 1999 Elsevier Science Ltd. All righ ts reserved.