RED-BLOOD-CELL ANTIOXIDANTS IN HUMAN VOLUNTEERS EXPOSED TO OZONE

Indices of red blood cell (RBC) antioxidant capacity can undergo chang es upon exposure to oxidants, either acutely or chronically. To invest igate whether these changes might provide a biochemical marker for acu te environmental ozone exposure, we assessed RBC glutathione (GSH) and catalase (CAT) responses in seven normal volunteers exposed to 0.16 p pm ozone for 7.5 hours compared to the same measurements following sha m exposure to clean air. For each subject, an interim period of two we eks separated the two exposure studies. Investigators performing the R BC assays were unaware of the environmental conditions. No changes in either GSH or CAT were observed for any study condition when compared to pre-study values. Our conclusion is that RBC antioxidants do not ac curately reflect in vivo exposure to ozone at concentrations readily a ttainable during periods of heavy urban pollution. Our data dispute th e value of these indices as markers of acute environmental photochemic al oxidant exposure.