#DEFVAR
 NO          = N + O ;       {nitric oxide}
 NO2         = N + 2O ;      {nitrogen dioxide}
 NO3         = N + 3O ;      {nitrogen trioxide}
 N2O5        = 2N + 5O ;     {dinitrogen pentoxide}
 HONO        = H + 2O + N ;  {nitrous acid}
 HNO3        = H + N + 3O ;  { nitric acid }
 PNA         = H + 4 O + N ; {HO2NO2 peroxynitric acid}
 O1D_CB4     = O ;           {oxygen atomic first singlet state}
 O           = O ;           {oxygen atomic ground state (3P)}
 HO          = O + H ;       {hydroxyl radical}
 O3          = 3O ;          {ozone}
 HO2         = H + 2O ;      {perhydroxyl radical}
 H2O2        = 2H + 2O ;     {hydrogen peroxide}
 HCHO        = C + 2H + O ;  {formalydehyde}
 ALD2        = IGNORE ;      {high molecular weight aldehides}
 C2O3        = 2C + 3H + 3O ; {CH3CO(O)OO peroxyacyl radical}
 PAN         = 2C + 3H + 5O + N ; {CH3C(O)OONO2, peroxyacyl nitrate}
 PAR         = IGNORE ;      {parafin carbon bond}
 ROR         = IGNORE ;      {secondary organic oxy radical}
 OLE         = IGNORE ;      {olefinic carbon bond}
 ETH         = 2C + 4H ;     {CH2=CH2 ethene}
 TOL         = 7C + 8H ;     {C6H5-CH3 toluene}
 CRES        = IGNORE ;      {cresol and h.m.w. phenols}
 TO2         = IGNORE ;      {toluene-hydroxyl radical adduct}
 CRO         = IGNORE ;      {methylphenoxy radical}
 OPEN        = IGNORE ;      {h.m.w. aromatic oxidation ring fragment}
 XYL         = 8C + 10H ;    {C6H4-(CH3)2 xylene}
 MGLY        = 3C + 4H + 2O ; {CH3C(O)C(O)H methylglyoxal}
 ISOP        = IGNORE ;      {isoprene}
 XO2         = IGNORE ;      {NO-to-NO2 operation}
 XO2N        = IGNORE ;      {NO-to-nitrate operation}          
 CO          = C + O ;       {carbon monoxide}
#DEFFIX
 H2O = H + 2O ;      {water}