Observations of acyl peroxy nitrates during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ)
Zaragoza J, Callahan S, McDuffie EE, Kirkland J, Brophy P, Durrett L, Farmer DK, Zhou Y, Sive B, Flocke F, Pfister G, Knote C, Tevlin A, Murphy J, Fischer EV. 2017. Observations of acyl peroxy nitrates during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ). Journal of Geophysical Research: Atmospheres. 122:12416-12,432
We report on measurements of acyl peroxy nitrates (APNs) obtained from two ground sites andthe NSF/National Center for Atmospheric Research C-130 aircraft during the 2014 Front Range Air Pollutionand Photochemistry Éxperiment (FRAPPÉ). The relative abundance of the APNs observed at the BoulderAtmospheric Observatory (BAO) indicates that anthropogenic emissions of volatile organic compounds(VOCs) are the dominant drivers of photochemistry during days with the most elevated peroxyacetyl nitrate(PAN). Reduced major axis regression between propionyl peroxynitrate (PPN) and PAN observed at BAOand from the C-130 produced a slope of 0.21 (R2= 0.92). Periods of lower PPN/PAN ratios (~0.10) wereassociated with cleaner background air characterized by lower ammonia and formic acid abundances. Theabundance of methacryloyl peroxynitrate relative to PAN only exceeded 0.05 at BAO when PAN mixing ratioswere<300 parts per trillion by volume, implying low influence of isoprene oxidation during periods withsubstantial local PAN production. We show an example of a day (19 July) where high O3was notaccompanied by enhanced local PAN production. The contribution of biogenic VOCs to local O3productionon the other days in July with elevated O3(22, 23, 28, and 29 July 2014) was small; evidence is provided inthe high abundance of PPN to PAN (slopes between 0.18 and 0.26). The PAN chemistry observed from surfaceand aircraft platforms during FRAPPÉ implies that anthropogenic VOCs played a dominant role in PANproduction during periods with the most O3and that the relative importance of biogenic hydrocarbonchemistry decreased with increasing O3production during FRAPPÉ.
- Type
- Journal Article
- Authors
- Zaragoza, J; Callahan, S; McDuffie, E; Kirkland, J; Brophy, P; Durrett, L; Farmer, D; Zhou, Y; Sive, B; Flocke, F; Pfister, G; Knote, C; Tevlin, A; Murphy, J; Fischer, E
- Units
- ARD
- Keywords
- air, ARD, ARD_Park-Air-Info_Collection, nitrogen, ozone, VOCs