Peroxy Radical Measurements Aboard the NASA P-3B during TRACE-P

Peroxy radicals (HO₂ and HO_xRO_x) were measured aboard the NASA P-3B aircraft during the TRACE-P mission in Spring 2001. Concentrations were quantified using PerCIMS (peroxy radical chemical ionization mass spectroscopy) which is based on chemical conversion of ambient radicals into gas phase sulfuric acid followed by ionization, ion separation, and detection. The behavior of peroxy radicals in the TRACE-P measurement region (western Pacific basin) will be discussed and compared with measurements during other recent photochemistry studies.