Monoterpene nitrate scheme

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This page documents the monoterpene nitrate mechanism used in Fisher et al., 2016 (under review in Atmospheric Chemistry and Physics). This is an experimental mechanism that has not yet been included in the standard GEOS-Chem simulation.

Basis of the Implementation

This chemistry is largely based on the scheme developed by Browne et al. (2014) for use in WRF-Chem, which was built on the RACM2 scheme developed by Goliff et al. (2013).



The following table lists the new species included in the mechanism, their name in Browne et al. (2014), and whether they are treated as transported tracers:

Species Browne Species Transported Tracer? Note
API API Yes alpha-pinene & other cyclic terpenes with one double bond
LIM LIM Yes limonene & other cyclice terpenes with two double bonds
PIP OP2 No peroxides from API & LIM
OLND TOLND No NO3-alkene adduct that primarily decomposes; from monoterpenes only here
OLNN TOLNN No NO3-alkene adduct that primarily retains the NO3 funcitonal group; from monoterpenes only here
MONITS TONIT No saturated first gen monoterpene organic nitrate
MONITU UTONIT No unsaturated first gen monoterpene organic nitrate
MONIT n/a Yes first generation monoterpene organic nitrate tracer combines species MONIT=MONITU+MONITS (like ISOPN, MMN)
HONIT HONIT No 2nd gen monoterpene nitrate

Kinetic reactions

The following table lists the new kinetic reactions included in the monoterpene nitrate scheme:

Reactants Products Rate Constant
API + OH APIO2 1.21E-11*exp(440/T)
APIO2 + NO 0.82HO2 + 0.82NO2 + 0.23HCHO+ 0.43 RCHO + 0.11 ACET + 0.44MEK + 0.07 HCOOH + 0.12MONITS + 0.06MONITU 4.00E-12
APIO2 + HO2 PIP 1.50E-11
APIO2 + MO2 HO2 + 0.75HCHO + 0.25 MOH + 0.25 ROH + 0.75RCHO + 0.75MEK 3.56E-14*exp(708/T)
APIO2 + MCO3 0.5 HO2 + 0.5 MO2 + RCHO + MEK + RCOOH 7.40E-13*exp(765/T)
APIO2 + NO3 HO2 + NO2 + RCHO + MEK 1.20E-12
API + O3 0.85OH + 0.1HO2 + 0.62 KO2 + 0.14 CO + 0.02 H2O2 + 0.65RCHO + 0.53MEK 5.0E-16*exp(-530/T)
API + NO3 0.1OLNN + 0.9 OLND 1.19E-12*exp(490/T)


  1. Browne, E. C., Wooldridge, P. J., Min, K.-E., and Cohen, R. C.: On the role of monoterpene chemistry in the remote continental boundary layer, Atmospheric Chemistry and Physics, 14, 1225–1238, doi:10.5194/acp-14-1225-2014,, 2014.
  2. Fisher, J.A., D.J. Jacob, K.R. Travis, P.S. Kim, E.A. Marais, C. Chan Miller, K. Yu, L. Zhu, R.M. Yantosca, M.P. Sulprizio, J. Mao, P.O. Wennberg, J.D. Crounse, A.P. Teng, T.B. Nguyen, J.M. St Clair, R.C. Cohen, P. Romer, B.A. Nault, P.J. Wooldridge, J.L. Jimenez, P. Campuzano-Jost, D.A. Day, P.B. Shepson, F. Xiong, D.R. Blake, A.H. Goldstein, P.K. Misztal, T.F. Hanisco, G.M. Wolfe, T.B. Ryerson, A. Wisthaler, T. Mikoviny: Organic nitrate chemistry and its implications for nitrogen budgets in an isoprene- and monoterpene-rich atmosphere: constraints from aircraft (SEAC4RS) and ground-based (SOAS) observations in the Southeast US, submitted to Atmospheric Chemistry & Physics, 2016.
  3. Goliff, W. S., Stockwell, W. R., and Lawson, C. V.: The regional atmospheric chemistry mechanism, version 2, Atmospheric Environment, 68, 174 – 185,, 2013.