Monitoring of peroxy radicals by chemical amplification enhanced photoacoustic spectroscopy

Peroxy radicals (HO 2 +RO 2 ) are crucial intermediates in many key atmospheric processes and contribute to the formation of major air pollutants, such as ozone and secondary organic aerosols 1 . Due to their high reactivity and their extremely low concentrations (typically <100 pptv), in-situ real time and interference-free measurements of peroxy radicals remain challenging.