# CRACMM1 Species Table

Gas (G) and particle (P) species from the namelists. SMILES link to representative structures in the EPA Chemicals Dashboard (if available).

Note that for each particulate species in CMAQ, a letter will be appended to the name to designate the size, or mode, of the aerosol being represented: I = Aitken mode, J = Accumulation mode, K = Coarse mode. Prepending of a species with a V or A in CMAQ or the chemical mechanism files indicates the species resides in the gas or particulate phase. 

 <sub>Species</sub> | <sub>Description</sub> | <sub>Phase</sub> | <sub>Molecular Weight (g/mol)</sub> | <sub>Explicit/ Lumped</sub> | <sub>Representative Structure</sub> | <sub>SMILES</sub> 
 ----- | ----- | ----- | ----- | ----- | ----- | ----- 
AAL|Aluminum ion|P|27.0|E|Aluminum ion|[\[Al+3\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID70912343)
ACA|Calcium ion|P|40.1|E|Calcium ion|[\[Ca++\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID7037638)
ACD|Acetaldehyde |G|44.0|E|Acetaldehyde|[CC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5039224)
ACE|Acetylene |G|26.0|E|Acetylene|[C#C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6026379)
ACL|Chloride ion|P|35.5|E|Chloride ion|[\[Cl-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6043969)
ACO3|Acetyl peroxy radicals|G|75.0|E|Acetylperoxy|[CC\(=O\)O\[O\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID40957943)
ACORS|Primary unspeciated coarse PM|P|100.0|L|Coarse PM|
ACRO|Acrolein|G|56.1|E|Acrolein|[C=CC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5020023)
ACT|Acetone|G|58.0|E|Acetone|[CC\(C\)=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8021482)
ACTP|Peroxy radicals formed from ACT|G|89.0|E|(2-oxopropyl)peroxy|CC\(=O\)CO\[O\]
ADCN|Aromatic-NO3 adduct from PHEN|G|155.0|L|4-oxocyclohex-2-en-1-yl nitrate|OC1=C\[C\]C\(O\[N+\]\(\[O-\]\)=O\)C=C1
ADDC|Aromatic-HO adduct from CSL|G|125.0|L|3-methyl-5-oxocyclohex-3-en-1-yloxidanyl|CC1=CC\(O\)=CC\(\[O\]\)C1
AEC|Elemental carbon|P|12.0|L|Carbon|\[C\]
AFE|Iron ion|P|55.8|E|Iron ion|[\[Fe++\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID4042672)
AGLY|SOA from reactive uptake of glyoxal on particles|P|66.4|L|2-(4,5-dihydroxy-1,3-dioxolan-2-yl)-1,3-dioxolane-4,5-diol|OC2OC\(C1OC\(O\)C\(O\)O1\)OC2O
AH2O|Water associated with particulate inorganic compounds|P|18.0|E|Water|[O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6026296)
AH3OP|Hydronium ion tracer|P|19.0|E|Hydronium ion|[\[OH3+\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID20893597)
AISO3NOS|Non-sulfated SOA from IEPOX uptake|P|136.2|L|2-methylbutane-1,2,3,4-tetrol|C\(O\)C\(O\)\(C\)C\(O\)CO
AISO3OS|Organosulfate SOA from IEPOX uptake|P|216.2|L|(1,3,4-trihydroxy-2-methylbutan-2-yl)oxysulfonic acid|C\(O\)C\(OS\(O\)\(=O\)\(=O\)\)\(C\)C\(O\)CO
AK|Potassium ion|P|39.1|E|Potassium ion|[\[K+\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID9042671)
ALD|C3 and higher aldehydes|G|58.0|L|Propanal|[CCC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2021658)
AMG|Magnesium ion|P|24.3|E|Magnesium ion|\[Mg++\]
AMN|Manganese ion|P|54.9|L|Manganese ions|[\[Mn++\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID00167687)
ANA|Sodium ion|P|23.0|E|Sodium ion|[\[Na+\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8037671)
ANH4|Ammonium ion|P|18.0|E|Ammonium ion|[\[NH4+\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5043974)
ANO3|Nitrate ion|P|62.0|E|Nitrate ion|[\[N+\]\(=O\)\(\[O-\]\)\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5024217)
AORGC|SOA from cloud processing of GLY and MGLY|P|177.0|L|2-(4,5-dihydroxy-1,3-dioxolan-2-yl)-1,3-dioxolane-4,5-diol|OC2OC\(C1OC\(O\)C\(O\)O1\)OC2O
AORGH2O|Water associated with particulate organic compounds|P|18.0|E|Water|[O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6026296)
AOTHR|Primary unspeciated fine PM|P|200.0|L|Unspeciated PM|
API|Alpha-pinenes and other cyclic terpenes with one double bond|G|136.4|L|alpha-pinene|[CC1=CCC2CC1C2\(C\)C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID4026501)
APINP1|Peroxy radicals from API+NO3 that do not undergo autoxidation|G|230.0|L|[2,6,6-trimethyl-3-(nitrooxy)bicyclo[3.1.1]heptan-2-yl]peroxy|\[O\]OC1\(C\)C\(ON\(=O\)=O\)CC2CC1C2\(C\)C
APINP2|Peroxy radicals from API+NO3 that undergo autoxidation|G|230.0|L|[2,6,6-trimethyl-3-(nitrooxy)bicyclo[3.1.1]heptan-2-yl]peroxy|\[O\]OC1\(C\)C\(ON\(=O\)=O\)CC2CC1C2\(C\)C
APIP1|Peroxy radicals from API+OH that do not undergo autoxidation|G|185.0|L|{3-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-2-yl}peroxy|\[O\]OC1\(C\)C\(O\)CC2CC1C2\(C\)C
APIP2|Peroxy radicals from API+OH that undergo autoxidation|G|185.0|L|{3-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-2-yl}peroxy|\[O\]OC1\(C\)C\(O\)CC2CC1C2\(C\)C
APNCOM|Primary non-carbon organic matter (legacy)|P|220.0|L|Non-carbon organic matter|
APOC|Primary organic carbon (legacy)|P|220.0|L|Organic carbon|
ASEACAT|Sea spray cations|P|23.75|L|Coarse sea spray cations|
ASI|Silicon|P|28.1|E|Total Silicon|[\[Si\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0051441)
ASO4|Total sulfur IV as sulfate|P|96.0|L|Sulfate ion|[\[O-\]S\(=O\)\(=O\)\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3042425)
ASOAT|An empirical SOA|P|200.0|L|3,4,5,6,7-Pentahydroxyheptan-2-one|[CC\(=O\)C\(C\(C\(C\(CO\)O\)O\)O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID80956455)
ASOIL|Lumped crustal species|P|100.0|L|Crustal species|
ATI|Titanium|P|47.9|E|Total Titanium|[\[Ti\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3047764)
BAL1|Peroxy radicals formed from BALD |G|123.0|L|(4-methylphenyl)peroxy|\[O\]OC1=CC=C\(C\)C=C1
BAL2|Peroxy radicals formed from BALD |G|109.0|L|phenylperoxy|\[O\]OC1=CC=CC=C1
BALD|Benzaldehyde and other aromatic aldehydes|G|106.0|L|Benzaldehyde|[O=CC1=CC=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8039241)
BALP|Peroxy radicals formed from BALD |G|137.0|L|benzoylperoxy|O=C\(O\[O\]\)C1=CC=CC=C1
BDE13|1,3-butadiene|G|54.1|E|1,3-Butadiene|[C=CC=C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3020203)
BDE13P|Peroxy radicals from BDE13|G|103.0|L|(1-hydroxybut-3-en-2-yl)peroxy|C=CC\(O\[O\]\)CO
BEN|Benzene|G|78.11|E|Benzene|[C1=CC=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3039242)
BENP|Peroxy radicals formed from benzene|G|159.12|L|{8-hydroxy-6,7-dioxabicyclo[3.2.1]oct-3-en-2-yl}peroxy|\[O\]OC1C=CC2OOC1C2O
CHO|Phenoxy radical formed from CSL|G|139.0|L|4-hydroxy-3,5-dimethylcyclohexa-2,5-dien-1-yloxidanyl|\[O\]C1C=C\(C\)C\(O\)C\(=C1\)C
CO|Carbon monoxide|G|28.0|E|Carbon monoxide|[\[C-\]#\[O+\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5027273)
CSL|Cresol and other hydroxy substituted aromatics |G|136.2|L|2-Phenylpropan-2-ol|[CC\(C\)\(O\)C1=CC=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3027247)
DCB1|Unsaturated dicarbonyls|G|98.0|L|2-methylbut-2-enedial|O=CC=C\(C\)C=O
DCB2|Unsaturated dicarbonyls|G|112.1|L|2-methyl-4-oxopent-2-enal|O=CC\(=CC\(=O\)C\)C
DCB3|Unsaturated dicarbonyls|G|84.0|L|but-2-enedial|O=CC=CC=O
ELHOM|Extremely-low volatility highly oxygenated molecules from terpenes|GP|402.0|L|6-hydroperoxy-7-({3-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-2-yl}peroxy)-3,3,6-trimethyl-tetrahydro-3aH-1,2-benzodioxol-5-ol|OC1CC2C\(OOC2\(C\)C\)C\(OOC3\(C\)C4C\(C\)\(C\)C\(C4\)CC3O\)C1\(C\)OO
EOH|Ethanol|G|46.1|E|Ethanol|[CCO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID9020584)
ETE|ethene |G|28.1|E|Ethylene|[C=C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1026378)
ETEG|Ethylene glycol|G|62.1|E|Ethylene glycol|[OCCO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8020597)
ETEP|Peroxy radicals formed from ETE|G|77.0|E|(2-hydroxyethyl)peroxy|OCCO\[O\]
ETH|ethane |G|30.1|E|Ethane|[CC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6026377)
ETHP|Peroxy radicals formed from ethane and other species |G|61.0|L|Ethylperoxy|[CCO\[O\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID90953652)
FURAN|Furans and other dienes|G|96.1|L|Furfural|[O=CC1=CC=CO1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1020647)
FURANO2|Peroxy radicals from FURAN oxidation|G|145.1|L|(2-formyl-5-hydroxy-5H-furan-2-yl)peroxy|OC1C=CC\(O1\)\(O\[O\]\)\(C=O\)
FURANONE|Ring-retaining ketone product from FURAN oxidation|G|100.1|L|2-hydroxy-2H-furan-5-one|[C1=CC\(=O\)OC1O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID10930763)
GLY|Glyoxal and glycoaldehydes |G|58.0|L|Glyoxal|[O=CC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5025364)
H2O2|Hydrogen peroxide|G|34.0|E|Hydrogen peroxide|[OO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2020715)
HC10|Alkanes and other species with HO rate constant greater than 6.8x10<sup>-12</sup> cm<sup>3</sup> s<sup>-1</sup>|G|142.28|L|Decane|[CCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6024913)
HC10P|Peroxy radicals formed from HC10 |G|173.27|L|Decan-3-ylperoxy|CCCCCCCC\(CC\)O\[O\]
HC10P2|Hydroxy peroxy radicals from HC10P alkoxy product|G|189.27|L|(8-hydroxydecan-5-yl)peroxy|CCCCC\(O\[O\]\)CCC\(O\)CC
HC3|Alkanes and other species with HO rate constant less than 3.4x10<sup>-12</sup> cm<sup>3</sup> s<sup>-1</sup> |G|44.1|L|Propane|[CCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5026386)
HC3P|Peroxy radicals formed from HC3|G|75.0|L|Isopropyl peroxy|CC\(C\)O\[O\]
HC5|Alkanes and other species with HO rate constant between 3.4x10<sup>-12</sup> and 6.8x10<sup>-12</sup> cm<sup>3</sup> s<sup>-1</sup> |G|72.1|L|Pentane|[CCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2025846)
HC5P|Peroxy radicals formed from HC5|G|103.0|L|Pentan-3-ylperoxy|CCC\(O\[O\]\)CC
HCHO|Formaldehyde |G|30.0|E|Formaldehyde|[C=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID7020637)
HCL|Hydrochloric acid|G|36.0|E|Hydrochloric acid|[Cl](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2020711)
HKET|Hydroxy ketone |G|74.0|L|Hydroxy acetone|[CC\(=O\)CO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8051590)
HNO3|Nitric acid|G|63.0|E|Nitric acid|[\[N+\]\(=O\)\(O\)\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5029685)
HNO4|Pernitric acid |G|79.0|E|Hydroxy nitrate|[\[N+\]\(=O\)\(\[O-\]\)OO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID201030501)
HO|Hydroxy radical|G|17.0|E|Hydroxyl radical|\[OH\]
HO2|Hydroperoxy radical|G|33.0|E|Hydroperoxy|[O\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID30894777)
HOM|Highly oxygenated molecules from terpenes|GP|250.0|L|6,7-dihydroperoxy-3,3,6-trimethyl-tetrahydro-3aH-1,2-benzodioxol-5-ol|OC1CC2C\(OOC2\(C\)C\)C\(OO\)C1\(C\)OO
HONO|Nitrous acid |G|47.0|E|Nitrous acid|[N\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID7064813)
IEPOX|isoprene epoxydiols |G|118.1|E|Isoprene epoxydiol|OCC1OC1\(C\)CO
IEPOXP|IEPOX intermediate (tracking species)|G|118.1||NA|
ISHP|Beta-hydroxy hydroperoxides from ISOP+HO2|G|118.0|L|2-hydroperoxy-2-methylbut-3-en-1-ol|C=CC\(OO\)\(CO\)C
ISO|Isoprene |G|68.1|E|Isoprene|[CC\(=C\)C=C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2020761)
ISON|Beta-hydroxyalkylnitrates from ISOP+NO alkylnitrates from ISO+NO3|G|147.0|L|2-methyl-2-(nitrooxy)but-3-en-1-ol|OCC\(C\)\(C=C\)ON\(=O\)=O
ISOP|Peroxy radicals formed from ISO+HO |G|117.0|L|(1-hydroxy-3-methylbut-3-en-2-yl)peroxy|OCC\(O\[O\]\)C\(C\)=C
KET|ketones|G|86.0|L|Diethylketone|[CCC\(=O\)CC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6021820)
KETP|Peroxy radicals formed from KET|G|117.0|L|(3-oxopentan-2-yl)peroxy|CCC\(C\(C\)O\[O\]\)=O
LIM|d-limonene and other cyclic diene-terpenes |G|136.3|L|D-Limonene|[CC\(=C\)\[C@@H\]1CCC\(C\)=CC1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1020778)
LIMAL|Limonene aldehyde and similar LIM-derived aldehydes|G|168.0|L|Limonaldehyde|O=CCC\(CCC\(=O\)C\)C\(=C\)C
LIMALP|Peroxy radicals from LIMAL|G|217.0|L|[1-hydroxy-2-methyl-5-oxo-3-(3-oxobutyl)pentan-2-yl]peroxy|O=CCC\(CCC\(=O\)C\)C\(C\)\(CO\)O\[O\]
LIMNP1|Peroxy radicals from LIM+NO3 that do not undergo autoxidation|G|230.0|L|[1-methyl-2-(nitrooxy)-4-(prop-1-en-2-yl)cyclohexyl]peroxy|\[O-\]\[N+\]\(=O\)OC1CC\(CCC1\(C\)O\[O\]\)C\(=C\)C
LIMNP2|Peroxy radicals from LIM+NO3 that undergo autoxidation|G|230.0|L|[1-methyl-2-(nitrooxy)-4-(prop-1-en-2-yl)cyclohexyl]peroxy|\[O-\]\[N+\]\(=O\)OC1CC\(CCC1\(C\)O\[O\]\)C\(=C\)C
LIMP1|Peroxy radicals from LIM+OH that do not undergo autoxidation|G|185.0|L|[2-hydroxy-1-methyl-4-(prop-1-en-2-yl)cyclohexyl]peroxy|\[O\]OC1\(C\)CCC\(CC1O\)C\(=C\)C
LIMP2|Peroxy radicals from LIM+OH that undergo autoxidation|G|185.0|L|[2-hydroxy-1-methyl-4-(prop-1-en-2-yl)cyclohexyl]peroxy|\[O\]OC1\(C\)CCC\(CC1O\)C\(=C\)C
MACP|Peroxy radicals formed from MACR+HO|G|101.0|L|(2-methylprop-2-enoyl)peroxy|CC\(=C\)C\(=O\)O\[O\]
MACR|methacrolein and other C4 aldehydes |G|70.0|L|Methacrolein|[CC\(=C\)C=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0052540)
MAHP|Hydroperoxides from MACP+HO2 |G|102.0|L|2-methylprop-2-eneperoxoic acid|C=C\(C\)C\(OO\)=O
MCP|Peroxy radical formed from MACR + HO which does not form MPAN|G|119.0|L|(1-hydroxy-2-methyl-3-oxopropan-2-yl)peroxy|OCC\(C\)\(O\[O\]\)C=O
MCT|Methyl catechol|G|124.1|L|4-Methylcatechol|[CC1=CC\(O\)=C\(O\)C=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5020861)
MCTO|Alkoxy radical formed from MCT+HO and MCT+NO3|G|123.0|L|3-hydroxy-5-methylphenyloxidanyl|CC1=CC\(O\)=CC\(\[O\]\)=C1
MCTP|Radical formed fro MCT+O3 reaction |G|172.0|L|C7H8O5 Biradical|CC\(/C=C\\[C\]\(O\[O\]\)O\)=C/C\(O\)=O
MEK|Methyl ethyl ketone|G|72.1|E|Methyl ethyl ketone|[CCC\(C\)=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3021516)
MEKP|Peroxy radicals formed from MEK|G|103.0|L|(3-oxobutyl)peroxy|\[O\]OCCC\(=O\)C
MGLY|Methylglyoxal and other alpha-carbonyl aldehydes |G|72.0|L|Methyl glyoxal|[CC\(=O\)C=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0021628)
MO2|Methyl peroxy radical|G|47.0|E|Methylperoxy|[CO\[O\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID10944007)
MOH|Methanol |G|32.0|E|Methanol|[CO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2021731)
MPAN|Peroxymethacryloylnitrate and other higher peroxyacylnitrates from isoprene oxidation|G|147.1|L|Peroxymethacryloyl nitrate|[O=N\(=O\)OOC\(=O\)C\(=C\)C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID10236878)
MVK|Methyl vinyl ketone|G|70.1|E|Methyl vinyl ketone|[CC\(=O\)C=C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3025671)
MVKP|Peroxy radicals formed from MVK|G|119.0|L|(2-hydroxy-3-oxobutyl)peroxy|CC\(=O\)C\(O\)CO\[O\]
N2O5|Dinitrogen pentoxide |G|108.0|E|Dinitrogen pentoxide|[\[N+\]\(=O\)\(\[O-\]\)O\[N+\]\(=O\)\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID90143672)
NALD|Nitrooxyacetaldehyde |G|105.0|E|1-(nitrooxy)acetaldehyde|O=CCON\(=O\)=O
NAPH|Naphthalene and other PAHs|G|128.17|L|Naphthalene|[C1=CC2=CC=CC=C2C=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8020913)
NAPHP|Peroxy radicals from NAPH oxidation|G|209.17|L|{8-hydroxy-10,11-dioxatricyclo[7.2.1.0^{2,7}]dodeca-2,4,6-trien-12-yl}peroxy|C12=CC=CC=C1C3OOC\(C3O\[O\]\)C2\(O\)
NH3|Ammonia|G|17.0|E|Ammonia|[N](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0023872)
NO|Nitric oxide |G|30.0|E|Nitric oxide|[\[N\]=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1020938)
NO2|Nitrogen dioxide |G|46.0|E|Nitrogen dioxide|[N\(=O\)\[O\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID7020974)
NO3|Nitrogen trioxide|G|62.0|E|Nitrate radical|\[O\]N\(=O\)=O
NUM|Number of particles|P|1.0|L|Number of particles|
O1D|Excited state oxygen atom, O(1D) |G|16.0|E|Excited oxygen|[\[O\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID00170378)
O3|Ozone|G|48.0|E|Ozone|[\[O-\]\[O+\]=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0021098)
O3P|Ground state oxygen atom, O(3P)|G|16.0|E|Ground state oxygen|[\[O\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID00170378)
OLI|Internal alkenes |G|70.1|L|2-Methyl-2-butene|[CC=C\(C\)C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8027165)
OLIP|Peroxy radicals formed from OLI|G|119.0|L|(3-hydroxy-2-methylbutan-2-yl)peroxy|\[O\]OC\(C\)\(C\)C\(C\)O
OLND|NO3-alkene adduct reacting via decomposition |G|136.0|L|[1-(nitrooxy)propan-2-yl]peroxy|CC\(O\[O\]\)CO\[N+\]\(\[O-\]\)=O
OLNN|NO3-alkene adduct reacting to form carbonitrates + HO2 |G|136.0|L|[1-(nitrooxy)propan-2-yl]peroxy|CC\(O\[O\]\)CO\[N+\]\(\[O-\]\)=O
OLT|Terminal alkenes |G|42.0|L|1-Propene|[CC=C](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5021205)
OLTP|Peroxy radicals formed from OLT|G|91.0|L|(1-hydroxypropan-2-yl)peroxy|CC\(CO\)O\[O\]
ONIT|Organic nitrates|G|119.0|L|Butan-2-yl nitrate|[CCC\(C\)O\[N+\]\(=O\)\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID00871813)
OP1|Methyl hydrogen peroxide |G|48.0|E|Methyl hydroperoxide|[COO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID10184401)
OP2|Higher organic peroxides |G|62.0|L|Ethyl hydroperoxide|[CCOO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID70184402)
OP3|Semivolatile organic peroxide|GP|176.2|L|5-hydroperoxy-6-hydroxyoctan-3-one|CCC\(=O\)CC\(OO\)C\(O\)CC
OPB|Terpene-derived peroxides|G|186.2|L|2-hydroperoxy-2,6,6-trimethylbicyclo[3.1.1]heptan-3-ol|OOC1\(C\)C\(O\)CC2CC1C2\(C\)C
ORA1|Formic acid|G|46.0|E|Formic acid|[OC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2024115)
ORA2|Acetic acid and higher acids |G|60.2|L|Acetic acid|[CC\(O\)=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5024394)
ORAP|Peroxy radical formed from ORA2 + HO reaction|G|91.0|L|(carboxymethyl)peroxy|\[O\]OCC\(=O\)O
PAA|Peroxyacetic acids and higher analogs|G|76.0|L|Peroxyacetic acid|[CC\(=O\)OO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1025853)
PAN|Peroxyacetyl nitrate and higher saturated PANs |G|121.0|L|Peroxyacetyl nitrate|[CC\(=O\)OON\(=O\)=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID4062301)
PHEN|phenol and benzene diols|G|110.1|L|Resorcinol|[OC1=CC\(O\)=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2021238)
PINAL|Pinonaldehyde and similar APIN-derived aldehydes|G|168.0|L|Pinonaldehyde|O=CCC1CC\(C\(=O\)C\)C1\(C\)C
PINALP|Peroxy radicals from PINAL oxidation|G|199.0|L|[3-acetyl-2,2-dimethyl-1-(2-oxoethyl)cyclobutyl]peroxy|O=CCC1\(O\[O\]\)CC\(C\(=O\)C\)C1\(C\)C
PPN|Peroxypropionyl nitrate|G|135.0|E|Peroxypopionyl nitrate|[CCC\(=O\)OO\[N+\]\(=O\)\[O-\]](https://comptox.epa.gov/dashboard/chemical/details/DTXSID90206675)
PROG|Propylene glyocol and other 3 carbon dialcohols|G|76.1|E|1,2-Propylene glycol|[CC\(O\)CO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0021206)
RCO3|Higher saturated acyl peroxy radicals|G|89.0|L|Propanoylperoxy|CCC\(=O\)O\[O\]
ROCIOXY|Intermediate volatility oxygenated ROC species (directly emitted)|G|247.0|L|Decamethylcyclopentasiloxane|[C\[Si\]1\(C\)O\[Si\]\(C\)\(C\)O\[Si\]\(C\)\(C\)O\[Si\]\(C\)\(C\)O\[Si\]\(C\)\(C\)O1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1027184)
ROCN1ALK|Alkane-like ROC species with C* of 10<sup>-1</sup> &#956;g m<sup>-3</sup>|GP|408.8|L|5,9-Dimethylheptacosane|[CCCCCCCCCCCCCCCCCCC\(C\)CCCC\(C\)CCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID40823452)
ROCN1OXY1|Oxygenated ROC species with C* of 10<sup>-1</sup> &#956;g m<sup>-3</sup> and O:C of 0.1|GP|312.5|L|Arachidic Acid|[CCCCCCCCCCCCCCCCCCCC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1060134)
ROCN1OXY3|Oxygenated ROC species with C* of 10<sup>-1</sup> &#956;g m<sup>-3</sup> and O:C of 0.3|GP|230.3|L|DODECANEDIOIC ACID|[C\(CCCCCC\(=O\)O\)CCCCC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3027297)
ROCN1OXY6|Oxygenated ROC species with C* of 10<sup>-1</sup> &#956;g m<sup>-3</sup> and O:C of 0.6|GP|190.2|L|2-hydroxy-octanedioic acid|C\(CCC\(C\(=O\)O\)O\)CCC\(=O\)O
ROCN2ALK|Alkane-like ROC species with C* of 10<sup>-2</sup> &#956;g m<sup>-3</sup>|GP|422.83|L|Triacontane|[CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID0060935)
ROCN2OXY2|Oxygenated ROC species with C* of 10<sup>-1</sup> &#956;g m<sup>-3</sup> and O:C of 0.2|GP|282.4|L|12(S)-hydroxy-16-Heptadecynoic Acid|C#CCCC\[C@H\]\(CCCCCCCCCCC\(=O\)O\)O
ROCN2OXY4|Oxygenated ROC species with C* of 10<sup>-2</sup> &#956;g m<sup>-3</sup> and O:C of 0.4|GP|232.3|L|2-HYDROXYUNDECANEDIOIC ACID|[C\(CCCCC\(=O\)O\)CCCC\(C\(=O\)O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID90726525)
ROCN2OXY8|Oxygenated ROC species with C* of 10<sup>-2</sup> &#956;g m<sup>-3</sup> and O:C of 0.8|GP|194.2|L|3,4,5,6,7-Pentahydroxyheptan-2-one|[CC\(=O\)C\(C\(C\(C\(CO\)O\)O\)O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID80956455)
ROCP0ALK|Alkane-like ROC species with C* of 1 &#956;g m<sup>-3</sup>|GP|394.77|L|11-Methylheptacosane|[CCCCCCCCCCCCCCCCC\(C\)CCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID40333900)
ROCP0OXY2|Oxygenated ROC species with C* of 1 &#956;g m<sup>-3</sup> and O:C of 0.2|GP|242.4|L|3-oxotetradecanoic acid|[CCCCCCCCCCCC\(=O\)CC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID10332384)
ROCP0OXY4|Oxygenated ROC species with C* of 1 &#956;g m<sup>-3</sup> and O:C of 0.4|GP|202.3|L|DECANEDIOIC ACID|[C\(CCCCC\(=O\)O\)CCCC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID7026867)
ROCP1ALK|Alkane-like ROC species with C* of 10 &#956;g m<sup>-3</sup>|GP|380.75|L|Heptacosane|[CCCCCCCCCCCCCCCCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6058637)
ROCP1ALKP|Peroxy radicals from ROCP1ALK oxidation|G|411.74|L|heptacosan-3-ylperoxy|CCCCCCCCCCCCCCCCCCCCCCCCC\(CC\)O\[O\]
ROCP1ALKP2|Hydroxy peroxy radicals from ROCP1ALK alkoxy product|G|427.73|L|(3-hydroxyheptacosan-6-yl)peroxy|CCCCCCCCCCCCCCCCCCCCCC\(O\[O\]\)CCC\(O\)CC
ROCP1OXY1|Oxygenated ROC species with C* of 10 &#956;g m<sup>-3</sup> and O:C of 0.1|GP|270.5|L|HEPTADECANOIC ACID|[CCCCCCCCCCCCCCCCC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5021596)
ROCP1OXY3|Oxygenated ROC species with C* of 10 &#956;g m<sup>-3</sup> and O:C of 0.3|GP|202.3|L|11-hydroxyundecanoic acid|[C\(CCCCCO\)CCCCC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID40190136)
ROCP2ALK|Alkane-like ROC species with C* of 10<sup>+2</sup> &#956;g m<sup>-3</sup>|GP|338.66|L|Tetracosane|[CCCCCCCCCCCCCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8060955)
ROCP2ALKP|Peroxy radicals from ROCP2ALK oxidation|G|369.65|L|tetracosan-3-ylperoxy|CCCCCCCCCCCCCCCCCCCCCC\(CC\)O\[O\]
ROCP2ALKP2|Hydroxy peroxy radicals from ROCP2ALK alkoxy product|G|385.65|L|(3-hydroxytetracosan-6-yl)peroxy|CCCCCCCCCCCCCCCCCCC\(O\[O\]\)CCC\(O\)CC
ROCP2OXY2|Oxygenated ROC species with C* of 10<sup>+2</sup> &#956;g m<sup>-3</sup> and O:C of 0.2|GP|200.3|L|Dodecanoic Acid|[CCCCCCCCCCCC\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5021590)
ROCP3ALK|Alkane-like ROC species with C* of 10<sup>+3</sup> &#956;g m<sup>-3</sup>|GP|296.58|L|Heneicosane|[CCCCCCCCCCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID9047097)
ROCP3ALKP|Peroxy radicals from ROCP3ALK oxidation|G|327.57|L|henicosan-3-ylperoxy|CCCCCCCCCCCCCCCCCCC\(CC\)O\[O\]
ROCP3ALKP2|Hydroxy peroxy radicals from ROCP3ALK alkoxy product|G|343.57|L|(3-hydroxyhenicosan-6-yl)peroxy|CCCCCCCCCCCCCCCC\(O\[O\]\)CCC\(O\)CC
ROCP3OXY2|Oxygenated ROC species with C* of 10<sup>+3</sup> &#956;g m<sup>-3</sup> and O:C of 0.2|GP|186.3|L|11-hydroxyundecanal|C\(CCCCCO\)CCCCC=O
ROCP4ALK|Alkane-like ROC species with C* of 10<sup>+4</sup> &#956;g m<sup>-3</sup>|G|254.5|L|Octadecane|[CCCCCCCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID9047172)
ROCP4ALKP|Peroxy radicals from ROCP4ALK oxidation|G|285.49|L|octadecan-3-ylperoxy|CCCCCCCCCCCCCCCC\(CC\)O\[O\]
ROCP4ALKP2|Hydroxy peroxy radicals from ROCP4ALK alkoxy product|G|301.49|L|(3-hydroxyoctadecan-6-yl)peroxy|CCCCCCCCCCCCC\(O\[O\]\)CCC\(O\)CC
ROCP4OXY2|Oxygenated ROC species with C* of 10<sup>+4</sup> &#956;g m<sup>-3</sup> and O:C of 0.2|G|158.2|L|2-Ethylheptanoic Acid|[CCCCCC\(CC\)C\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID40880929)
ROCP5ALK|Alkane-like ROC species with C* of 10<sup>+5</sup> &#956;g m<sup>-3</sup>|G|198.39|L|Tetradecane|[CCCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID1027267)
ROCP5ALKP|Peroxy radicals from ROCP5ALK oxidation|G|229.38|L|tetradecan-3-ylperoxy|CCCCCCCCCCCC\(CC\)O\[O\]
ROCP5ALKP2|Hydroxy peroxy radicals from ROCP5ALK alkoxy product|G|245.38|L|(3-hydroxytetradecan-6-yl)peroxy|CCCCCCCCC\(O\[O\]\)CCC\(O\)CC
ROCP5ARO|Aromatic ROC species with C* of 10<sup>+5</sup> &#956;g m<sup>-3</sup>|G|190.33|L|Benzene, octyl-|[CCCCCCCCC1=CC=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2062240)
ROCP5AROP|Peroxy radicals from ROCP5ARO oxidation|G|271.33|L|{8-hydroxy-5-octyl-6,7-dioxabicyclo[3.2.1]oct-3-en-2-yl}peroxy|CCCCCCCCC1\(OO2\)C=CC\(O\[O\]\)C2C1O
ROCP5OXY1|Oxygenated ROC species with C* of 10<sup>+5</sup> &#956;g m<sup>-3</sup> and O:C of 0.1|G|170.3|L|Undecanal|[CCCCCCCCCCC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID4021688)
ROCP6ALK|Alkane-like ROC species with C* of 10<sup>+6</sup> &#956;g m<sup>-3</sup>|G|184.37|L|Tridecane|[CCCCCCCCCCCCC](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6027266)
ROCP6ALKP|Peroxy radicals from ROCP6ALK oxidation|G|215.36|L|tridecan-3-ylperoxy|CCCCCCCCCCC\(CC\)O\[O\]
ROCP6ALKP2|Hydroxy peroxy radicals from ROCP6ALK alkoxy product|G|231.36|L|(3-hydroxytridecan-6-yl)peroxy|CCCCCCCC\(O\[O\]\)CCC\(O\)CC
ROCP6ARO|Aromatic ROC species with C* of 10<sup>+6</sup> &#956;g m<sup>-3</sup>|G|176.3|L|1-Hexyl-4-methylbenzene|[CCCCCCC1=CC=C\(C\)C=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID30333914)
ROCP6AROP|Peroxy radicals from ROCP6ARO oxidation|G|257.3|L|{2-hexyl-8-hydroxy-5-methyl-6,7-dioxabicyclo[3.2.1]oct-3-en-2-yl}peroxy|OC1C2C\(CCCCCC\)\(O\[O\]\)C=CC1\(C\)OO2
ROCP6OXY1|Oxygenated ROC species with C* of 10<sup>+6</sup> &#956;g m<sup>-3</sup> and O:C of 0.1|G|142.2|L|Nonanal|[CCCCCCCCC=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID9021639)
ROH|C3 and higher alcohols |G|60.0|L|Propanol|[CCCO](https://comptox.epa.gov/dashboard/chemical/details/DTXSID2021739)
SESQ|Sesquiterpenes |G|204.4|L|b-caryophyllene|[C/C1=C/CCC\(=C\)C2CC\(C\)\(C\)C2CC\1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID8024739)
SESQNRO2|Peroxy radicals from SESQ reaction with nitrate radicals|G|298.4|L|[4,11,11-trimethyl-8-methylidene-5-(nitrooxy)bicyclo[7.2.0]undecan-4-yl]peroxy|\[O\]OC1\(C\)CCC2C\(CC2\(C\)C\)C\(=C\)CCC1O\[N+\]\(=O\)\[O-\]
SESQRO2|Peroxy radicals from SESQ reaction with OH|G|253.4|L|{5-hydroxy-4,11,11-trimethyl-8-methylidenebicyclo[7.2.0]undecan-4-yl}peroxy|\[O\]OC1\(C\)CCC2C\(CC2\(C\)C\)C\(=C\)CCC1O
SLOWROC|Slowly reacting ROC with k<sub>OH</sub>< 3.5x10<sup>-13</sup> cm<sup>3</sup> s<sup>-1</sup> |G|75.4|L|Hydrogen cyanide|[C#N](https://comptox.epa.gov/dashboard/chemical/details/DTXSID9024148)
SO2|Sulfur dioxide |G|64.0|E|Sulfur dioxide|[O=S=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6029672)
SRF|Surface area of particles|P|1.0|L|Surface area of particles|
SULF|Sulfuric acid|G|98.0|E|Sulfuric acid|[OS\(=O\)\(=O\)O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID5029683)
SULRXN|Precursor of Aerosol Sulfate (tracking species) |G|98.0||NA|
TOL|Toluene |G|92.14|E|Toluene|[CC1=CC=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID7021360)
TOLP|Peroxy radicals formed from TOL|G|173.14|L|{8-hydroxy-5-methyl-6,7-dioxabicyclo[3.2.1]oct-3-en-2-yl}peroxy|\[O\]OC1C=CC2\(C\)OOC1C2O
TRPN|Terpene nitrates|G|215.0|L|3-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-2-yl nitrate|O=N\(=O\)OC1\(C\)C\(O\)CC2CC1C2\(C\)C
UALD|Unsaturated aldehydes|G|84.1|L|2-Methylbut-2-enal|[CC=C\(C\)C=O](https://comptox.epa.gov/dashboard/chemical/details/DTXSID00859414)
UALP|Peroxy radicals formed from UALD |G|133.0|L|(3-hydroxy-3-methyl-4-oxobutan-2-yl)peroxy|CC\(O\[O\]\)C\(C\)\(O\)C=O
XO2|Accounts for addition NO to NO2 conversions (tracking species)|G|1.0||NA|
XYE|O- and p-xylene and other less reactive volatile aromatics with k<sub>OH</sub> < 1.46x10<sup>-11</sup> cm<sup>3</sup> s<sup>-1</sup> |G|106.2|L|Ethylbenzene|[CCC1=CC=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID3020596)
XYEP|Peroxy radicals formed from XYE|G|187.17|L|{5-ethyl-8-hydroxy-6,7-dioxabicyclo[3.2.1]oct-3-en-2-yl}peroxy|\[O\]OC1C=CC2\(CC\)OOC1C2O
XYM|M-xylene and other more reactive volatile aromatics with k<sub>OH</sub> > 1.46x10<sup>-11</sup> cm<sup>3</sup> s<sup>-1</sup> |G|106.2|L|m-Xylene|[CC1=CC\(C\)=CC=C1](https://comptox.epa.gov/dashboard/chemical/details/DTXSID6026298)
XYMP|Peroxy radicals formed from XYM|G|187.17|L|{8-hydroxy-1,5-dimethyl-6,7-dioxabicyclo[3.2.1]oct-3-en-2-yl}peroxy|\[O\]OC1C=CC2\(C\)OOC1\(C\)C2O

