In vivo and in vitro effect of ozone and formaldehyde on human nasal mucociliary transport system

The effect of ozone and formaldehyde on the nasal mucociliary transport system after short-term exposure was comparatively evaluated in human by using in vivo and in vitro test systems. Concentrations of ozone used were 10, 100, 500 and 1000 micrograms/m3 of ozone and of formaldehyde 100, 500 and 5000 micrograms/m3. The in vivo effect of ozone was monitored by measuring the saccharin transport time before and two hours after exposure to ozone. The in vitro effect of ozone and formaldehyde was evaluated by quantifying the ciliary beat frequency (CBF) of isolated respiratory epithelial cells before and after one, two, and three hours of exposure. Control experiments were performed using synthetic air. Ozone had no effect on the human nasal mucociliary transport system under the conditions tested here. Neither in vivo nor in vitro any significant changes of saccharin transport time nor CBF were measured. In contrast, formaldehyde significantly reduced (67.1%) CBF at the highest dosis (2 hours, 5000 micrograms/m3). These results will be discussed according to the environmental impact of ozone and formaldehyde in air pollutants and compared to sulphur dioxide and nitric oxide, which were tested under similar conditions, and to results revealed from animal experiments.