Relative rate constants for the heterogeneous reactions of OH, NO2 and NO radicals with polycyclic aromatic hydrocarbons adsorbed on carbonaceous particles. Part 1: PAHs adsorbed on 1–2 μm calibrated graphite particles

Abstract A discharge flow reactor was used to study the heterogeneous reactions of OH, NO 2 and NO radicals with 11 polycyclic aromatic hydrocarbons (PAHs) adsorbed on 1–2 μm calibrated graphite particles. Graphite was chosen as a simple model of carbonaceous atmospheric particles. Relative kinetic information was obtained from the decays of particulate-PAH concentration vs. the time, measured using off-line gas chromatography coupled to mass spectrometry. Particulate-anthracene, -benzo( a )pyrene and -perylene are the most reactive with NO 2 , whereas all PAHs studied present similar reactivities with OH within uncertainties. The reactivity of NO under our experimental conditions could not be distinguished from the PAH desorption.