On the use of an explicit chemical mechanism to dissect peroxy acetyl nitrate formation

abstract Peroxy acetyl nitrate (PAN) is a key component of photochemical smog and plays an important role inatmospheric chemistry. Though it has been known that PAN is produced via reactions of nitrogen oxides(NO x ) with some volatile organic compounds (VOCs), it is difficult to quantify the contributions of in-dividual precursor species. Here we use an explicit photochemical model e Master Chemical Mechanism(MCM) model e to dissect PAN formation and identify principal precursors, by analyzing measurementsmade in Beijing in summer 2008. PAN production was sensitive to both NO x and VOCs. Isoprene was thepredominant VOC precursor at suburb with biogenic impact, whilst anthropogenic hydrocarbonsdominated at downtown. PAN production was attributable to a relatively small class of compoundsincluding NO x , xylenes, trimethylbenzenes, trans/cis-2-butenes, toluene, and propene. MCM can advanceunderstanding of PAN photochemistry to a species level, and provide more relevant recommendationsfor mitigating photochemical pollution in large cities.© 2014 Elsevier Ltd. All rights reserved.