GECKOA Generator of Explicit Chemistry and Kinetics of

GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics) New products added to the stack Considered Precursors of SOA C 3 -25 alkanes, short alkenes and aromatics VOC 1 VOC 2 VOCn Radical? no C-H ? RO 2 ? Peroxy alkyl chemistry OH reaction O 3 reaction yes >C=C< ? RCO 3 ? NO 3 reaction Photolysis Peroxy acyl chemistry -CHO ? >C=O ? -ONO 2 ? -OOH ? -C(O)OONO 2 ? RO ? Alkoxy chemistry Thermal decomposition Treat next species in the stack

GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics) New products added to the stack Considered Precursors of SOA C 3 -25 alkanes, short alkenes and aromatics VOC 1 VOC 2 Radical? no C-H ? OH reaction RH + OH RO 2 >C=C< + OH >C(OH)C(O 2)< O 3 reaction >C=C< + O 3 >C=O + Criegee products + OH >C=C< ? -CHO ? >C=O ? -ONO 2 ? -OOH ? -C(O)OONO 2 ? Thermal decomposition RCO(OONO 2) RCO(OO)+NO 2 yes RO 2 ? Peroxy alkyl chemistry RO 2+NO RO+NO 2 RO 2+NO RONO 2 RO 2+NO 3 RO+NO 2+O 2 RO 2+HO 2 ROOH + O 2 RO 2+RO 2 products RCO 3 ? NO 3 reaction RCHO + NO 3 R(O)OO >C=C< + NO 3 >C(ONO 2)C(O 2)< Photolysis RCHO + hn R + HCO RONO 2 + hn RO + NO 2 ROOH + hn RO + OH VOCn Peroxy acyl chemistry RCO 3+NO R+CO 2+NO 2 RCO 3+NO 2 RCO(OONO 2) RCO 3+NO 3 R+CO 2+NO 2+O 2 RCO 3+HO 2 RCO(OOH) + O 2 RCO 3+HO 2 RCO(OH) + O 3 RCO 3+RO 2 products RO ? Alkoxy chemistry >CH(O )+O 2 >C=O + HO 2 >CH(O )C 2 C(O. )< >C(O ) C 2 C(OH)< >C(O )-R >C=O + R Treat next species in the stack