COMPARISON OF PEROXY RADICAL CONCENTRATIONS AT SEVERAL CONTRASTING SITES

The importance of the peroxy radicals in gas phase atmospheric chemist ry has prompted the development of a number of methods for their measu rement. These have resulted in several reports of HO2 and RO(2) levels around the globe. The chemical amplifier has been used for measuremen ts in seven intensive measurement campaigns over the last few years. T he measured levels tell a great deal about the tropospheric chemistry of these radicals and also tell much about our understanding of the pr ocesses that create and destroy them. The results of these measured le vels at sites that differ greatly in oxidant precursor concentration a s well as photochemical activity are compared. A steady-state model ha s been developed to help explain the radical observations, and its use is discussed.