A new parameterization of biogenic SOA formation based on smog chamber data: 3D testing in CMAQ Manuel Santiago 1, Ariel F. Stein 2, Marta G. Vivanco 1, Yunsoo Choi 3 and Rick Saylor 4 1 CIEMAT (Research Center for Energy, Environment and Technology). Madrid. SPAIN 2 ERT on assignment of NOAA/ARL, Silver Spring MD 3 NOAA/ARL, Silver Spring, MD 4 NOAA/ARL, Atmospheric Turbulence and Diffusion Division, Oak Ridge, TN 2011 CMAS Conference

Motivation  Biogenic SOA, accounts for the largest fraction of the global atmospheric aerosol  EUPHORE smog chamber experiments: CMAQ paramaters that govern SOA originated by terpenes clearly overestimate our experimental data.  Here, a semi-empirical parameterization based on product distribution given by BVOCs oxidation pathways is presented for  -pinene + limonene SOA

Terpene SOA in CMAQ v4.7  Based on the partition parameters obtained by Griffin et al Two Product Model for different BVOCs Griffin et al., 1999

Terpene SOA in CMAQ v4.7 Compound wght alpha1 Kom1 alpha2 Kom a-pinene b-pinene d3-carene sabinene limonene alpha1 cstar1 alpha2 cstar CMAQ TERPENE Straighforward implementation Lack of known of the product distributions for all the identified SOA precursor pathways Why two-product model?

Semiempirical Parameterization Theoretical K om,i calculation for individual SOA constituents  -pin + limo yield calculation Two product model fit (Based on theoretical constraints) Comparison with current CMAQ parameters

Smog Chamber Experiments  Outdoor chamber EUPHORE (CEAM, Valencia, Spain)  Approximated volume of 200 m 3  Biogenic VOCs mixture photooxidation experiments: (isoprene +  -pinene + limonene) + HONO

Smog Chamber Experiments ppb CHAMBER : ppb RURAL ATM. = 10 2 – 10 3 Exp.ISOAPINLIMOHONONONO 2 SO 2 ppbC/ppbNOxTRH ppb K%

 -pinene SOA products (Kamens and Jaoui, 2001) p o L,i (Torr) K om,i (m 3.  g -1 ) Limonene SOA products (Jaoui et al., 2006) p o L,i (Torr) K om,i (m 3.  g -1 ) Pinic acid 7.6E Limonic acid 6E Hydroxypinonic acid 7.1E hydroxylimononic acid 5.5E Ketolimonic acid 2.4E Ketonorlimononic acid 6.2E Pinonic acid 1.1E hydroxyketolimononic acid 2.2E Norpinonic acid 2.9E oxopinonic acid 1.3E Limononic acid 8.4E hydroxypinonaldehyde 1.1E Ketolimononic acid 3.3E Organic nitrate 1.2E Organic nitrate 1E m 3 /  g < K om,1 < 0.5 m 3 /  g 0.01 m 3 /  g < K om,2 < m 3 /  g Individual K om,i calculation The contribution method SIMPOL.1 (Pankow and Asher, 2008) was used for the calculation of individual p o L,i and K om,i

Y isoprene = 0.02  -pin + limo Yield Calculation  1 = K om,1 = m 3.  g -1  2 = 0.2 K om,2 = m 3.  g -1

Model Description CMAQ v4.7 simplified version: only gas phase chemistry and aerosol formation  Domain: 4 x 4 cell grid located in Valencia, Spain (LAT: 39, LON: 0)  Meteorology: Hourly T, P and QV values measured in the chamber  CCTM Conditions: Gas/Aerosol mechanism: CB05-AERO5 Solver: SMVGEAR Temporal Resolution: (hhmmss)

11 K om,1,298K (m 3.  g -1 ) cstar (m 3.  g -1 ) 22 K om,2,298K (m 3.  g -1 ) cstar (m 3.  g -1 ) TRP_originalAPIN LIMO TRP TRP_revisedAPIN LIMO TRP TRP_fitTRP Parameterizations to test TRP_original : Current parameters in CMAQ v4.7 (scale up of  i to consider 1.3 g/cc density) TRP_revised: re-derived parameters for 1.3 g/cc density (Carlton et al.2010) TRP_fit: parameters obtained in this work (Santiago et al., 2011, submitted to ES&T)

data alpha / , ! SV_ALK & , , ! SV_XYL1, SV_XYL2 & , , ! SV_TOL1, SV_TOL2 & , 1.162, ! SV_BNZ1, SV_BNZ2 & , , ! SV_TRP1, SV_TRP2 & 0.232, , ! SV_ISO1, SV_ISO2 & 1.3 / ! SV_SQT data cstar / 0.020, ! SV_ALK & 1.314, , ! SV_XYL1, SV_XYL2 & 2.326, , ! SV_TOL1, SV_TOL2 & 0.302, , ! SV_BNZ1, SV_BNZ2 & 7.466, , ! SV_TRP1, SV_TRP2 & , 0.617, ! SV_ISO1, SV_ISO2 & / ! SV_SQT Model Description orgaer5.f

Chamber Experiments Simulations

TRP_originalTRP_revisedTRP_fit Normalized Mean Bias (%)

CMAQ v4.7 3D Settings  Study Period: August 2009  Emissions: based on NEI 2005  Meteorology: NAM  Horizontal/Vertical Resolution: 12 km/22 layers  Boundary Conditions: GEOSCHEM monthly average  Chemical/Aerosol Mechanism: CB05-AE5

TRP_original SOA Monthly Average

Effect of different parameters TRP_original – TRP_revised TRP_original – TRP_fit

 A 2 product parameterization for SOA from  -pinene and limonene has been calculated with a mixed theoretical-experimental approach  Mechanistic considerations considered in TRP_fit represent an improvement of the treatment of SOA from  -pinene and limonene  Parameters re-derived by Carlton et al (TRP_revised) reduce original parameters bias by 50%. Still an overprediction is observed (NOx dependent SOA?) Summary  Differences in the chamber experiment simulations do not drive to substantial changes on the model response on SOA monthly average concentration  TRP_revised and TRP_fit show a similar reduction of the original CMAQ values (TRP_original).  Only  -pinene and limonene parameters have been calculated in this work. The same procedure should be done for the rest of terpenes SMOG CHAMBER EXPERIMENTS 3-D AUGUST 2009 SIMULATION