Ozone Removal, ultra fine particles, and VOC levels on sooty supply air filters in the presence of alphapinene

Ozone removal, concentration of ultrafine particles (2 to 64 nm), and VOCs were measured on sooty ventilation filters. A F8 class filter loaded by diesel soot particles in a motor laboratory and a heavily loaded F5 class filter used for 8 months in a bus service terminal were used in the tests. In addition, both filters were saturated with alphapinene vapor to examine possible formation of secondary aerosols by heterogeneous reactions. Both filters removed ozone effectively in the beginning. Then, the removal efficiency declined until it reached a steady state level in three hours.
Some particle formation was observed on both filters in the beginning of the test. Alphapinene disappeared from the air after F5 filter within three hours, whereas, its concentration remained almost on a constant level after the sooty F8 fine filter during the whole four hour test period