Supplementary Table 1.Campaign summary of VOCs analyzed in July 2011 at Edgewood MD. Average values of concentration and OH reactivity. The table is organized by decreasing OH reactivity.

VOC / Mean OH Reactivity s-1 / Mean Concentration ppbv / KOH(VOC) cm3 molecules-1 second-1 / VOC Class / VOC Source
Isoprene (2-Methyl-1,3-Butadiene) / 2.593 / 4.613 / 2.28E-11 / Alkenes / Biogenic
Acetaldehyde / 1.466 / 2.236 / 2.66E-11 / Oxygenated / Oxygenated
MVK / 0.502 / 1.094 / 1.86E-11 / Oxygenated / Biogenic
MAC (2-Methyl-2-propenal) / 0.360 / 0.453 / 3.22E-11 / Oxygenated / Biogenic
Hexanal / 0.287 / 0.422 / 2.76E-11 / Oxygenated / Oxygenated
Limonene / 0.261 / 0.066 / 1.60E-10 / Terpenes / Biogenic
Styrene / 0.232 / 0.089 / 1.06E-10 / Aromatics / Anthropogenic
Acrolein (2-Propenal) / 0.217 / 0.442 / 1.99E-11 / Oxygenated / Oxygenated
Benzaldehyde / 0.171 / 0.496 / 1.40E-11 / Oxygenated / Oxygenated
Butylaldehyde (Butanal) / 0.170 / 0.239 / 2.88E-11 / Oxygenated / Oxygenated
a-Pinene / 0.090 / 0.060 / 6.09E-11 / Terpenes / Biogenic
2-Methyl-Propanal (Isobutylaldehyde) / 0.085 / 0.130 / 2.65E-11 / Oxygenated / Oxygenated
2-Hexanone / 0.074 / 0.026 / 1.15E-10 / Oxygenated / Oxygenated
Pentanal / 0.073 / 0.119 / 2.48E-11 / Oxygenated / Oxygenated
Ethylene / 0.072 / 0.389 / 7.51E-12 / Alkenes / Biogenic
Chloromethane / 0.070 / 0.647 / 4.36E-12 / Halogenated / Other
1-Butene; 2-Methylpropene / 0.060 / 0.079 / 3.08E-11 / Alkenes / Anthropogenic
b-Pinene / 0.059 / 0.031 / 7.68E-11 / Terpenes / Biogenic
m,p-Xylene / 0.053 / 0.037 / 5.85E-11 / Aromatics / Anthropogenic
Propane / 0.051 / 1.203 / 1.72E-12 / Alkanes / Anthropogenic
2-Methylfuran / 0.049 / 0.018 / 1.11E-10 / Oxygenated / Oxygenated
3-Methylfuran / 0.044 / 0.019 / 9.37E-11 / Oxygenated / Oxygenated
Acetone / 0.028 / 5.035 / 2.23E-13 / Oxygenated / Oxygenated
1-Butanol (Butyl alcohol) / 0.022 / 0.102 / 8.66E-12 / Oxygenated / Oxygenated
2-Methylbutane / 0.021 / 0.247 / 3.50E-12 / Alkanes / Anthropogenic
Ethanol / 0.017 / 2.243 / 3.08E-13 / Oxygenated / Oxygenated
Isopropyl Alcohol / 0.017 / 0.137 / 4.93E-12 / Oxygenated / Oxygenated
Butane / 0.016 / 0.256 / 2.55E-12 / Alkanes / Anthropogenic
Ethane / 0.016 / 2.090 / 3.05E-13 / Alkanes / Anthropogenic
1-Pentene / 0.016 / 0.023 / 2.74E-11 / Alkenes / Other
MEK / 0.015 / 0.607 / 9.90E-13 / Oxygenated / Oxygenated
1-Hexene; 2-Methyl-1-Pentene / 0.012 / 0.013 / 3.70E-11 / Alkenes / Other
1,2,4-Trimethylbenzene / 0.012 / 0.015 / 3.25E-11 / Aromatics / Anthropogenic
1-Nonene / 0.012 / 0.011 / 4.32E-11 / Alkenes / Other
Camphene / 0.011 / 0.008 / 5.33E-11 / Terpenes / Biogenic
Pentane / 0.009 / 0.142 / 2.60E-12 / Alkanes / Anthropogenic
Propyl alcohol (1-Propanol) / 0.008 / 0.060 / 5.47E-12 / Oxygenated / Oxygenated
2-Methylpentane / 0.008 / 0.061 / 5.20E-12 / Alkanes / Other
2-Pentanone / 0.007 / 0.086 / 3.48E-12 / Oxygenated / Oxygenated
1-Heptene / 0.007 / 0.007 / 3.86E-11 / Alkenes / Other
Dodecane / 0.006 / 0.019 / 1.32E-11 / Alkanes / Other
MIBK / 0.006 / 0.019 / 1.22E-11 / Oxygenated / Oxygenated
2-Methyl-1-Butene / 0.006 / 0.004 / 5.20E-11 / Alkenes / Other
2-Butanol / 0.005 / 0.027 / 8.24E-12 / Oxygenated / Oxygenated
3-Ethyltoluene / 0.005 / 0.010 / 2.24E-11 / Aromatics / Anthropogenic
1,3-Butadiene / 0.005 / 0.003 / 6.76E-11 / Alkenes / Anthropogenic
3-Methylpentane / 0.005 / 0.039 / 5.20E-12 / Alkanes / Other
o-Xylene / 0.005 / 0.017 / 1.14E-11 / Aromatics / Anthropogenic
Naphthalene / 0.005 / 0.008 / 2.39E-11 / Aromatics / Anthropogenic
2,2,4-Trimethylpentane / 0.005 / 0.055 / 3.37E-12 / Alkanes / Other
Acetylene / 0.005 / 0.242 / 7.66E-13 / Alkynes / Anthropogenic
Methylcyclopentane / 0.005 / 0.021 / 8.60E-12 / Alkanes / Other
t-2-Pentene / 0.004 / 0.003 / 6.86E-11 / Alkenes / Other
Hexane / 0.004 / 0.043 / 4.02E-12 / Alkanes / Other
Undecane / 0.004 / 0.014 / 1.23E-11 / Alkanes / Other
2-Methyl-2-Butene / 0.004 / 0.002 / 8.30E-11 / Alkenes / Other
Methanol / 0.003 / 6.977 / 1.92E-14 / Oxygenated / Oxygenated
Heptane / 0.003 / 0.020 / 6.45E-12 / Alkanes / Anthropogenic
Decane / 0.003 / 0.011 / 1.10E-11 / Alkanes / Other
1,3,5-Trimethylbenzene / 0.003 / 0.002 / 5.15E-11 / Aromatics / Anthropogenic
Ethylbenzene / 0.003 / 0.018 / 6.07E-12 / Aromatics / Anthropogenic
2,3,4-Trimethylpentane / 0.003 / 0.017 / 6.52E-12 / Alkanes / Other
2-Heptanone / 0.003 / 0.017 / 6.28E-12 / Oxygenated / Oxygenated
Methylcyclohexane / 0.002 / 0.010 / 9.40E-12 / Alkanes / Other
Isobutylalcohol / 0.002 / 0.010 / 9.20E-12 / Oxygenated / Oxygenated
Nonane / 0.002 / 0.008 / 9.74E-12 / Alkanes / Other
Propyne / 0.002 / 0.026 / 3.11E-12 / Alkynes / Anthropogenic
2,3-Dimethylbutane / 0.002 / 0.013 / 5.79E-12 / Alkanes / Other
Cyclopentane / 0.002 / 0.015 / 5.01E-12 / Alkenes / Other
Octane / 0.002 / 0.010 / 7.52E-12 / Alkanes / Anthropogenic
iso-Propylbenzene / 0.002 / 0.011 / 6.61E-12 / Aromatics / Other
4-Ethyltoluene / 0.002 / 0.005 / 1.47E-11 / Aromatics / Anthropogenic
Carbon Disulfide / 0.002 / 0.053 / 1.20E-12 / Nitriles and Sulfides / Other
1-Undecene / 0.002 / 0.001 / 4.79E-11 / Alkenes / Other
p-Cymene (1-Methyl-4-Isopropylbenzene) / 0.001 / 0.004 / 1.51E-11 / Aromatics / Biogenic
Isobutane (2-Methylpropane) / 0.001 / 0.144 / 4.02E-13 / Alkanes / Anthropogenic
1,2,3-Trimethylbenzene / 0.001 / 0.002 / 3.27E-11 / Aromatics / Anthropogenic
Cyclohexane / 0.001 / 0.008 / 7.03E-12 / Alkanes / Anthropogenic
2-Ethyltoluene / 0.001 / 0.003 / 1.36E-11 / Aromatics / Anthropogenic
Cyclohexanone / 0.001 / 0.007 / 6.39E-12 / Oxygenated / Oxygenated
Ethylacetate / 0.001 / 0.028 / 1.69E-12 / Oxygenated / Oxygenated
Benzene / 0.001 / 0.080 / 5.86E-13 / Aromatics / Anthropogenic
Butylacetate / 0.001 / 0.007 / 5.78E-12 / Oxygenated / Oxygenated
2,4-Dimethylpentane / 0.001 / 0.007 / 5.48E-12 / Alkanes / Other
2,3-Dimethylpentane / 0.001 / 0.011 / 2.70E-12 / Alkanes / Other
Toluene / 0.001 / 0.123 / 2.29E-13 / Aromatics / Anthropogenic
c-2-Pentene / 0.001 / 0.000 / 6.38E-11 / Alkenes / Other
t-4-Methyl-2-Pentene / 0.001 / 0.000 / 6.24E-11 / Alkenes / Other
n-Propylbenzene / 0.001 / 0.004 / 5.71E-12 / Aromatics / Other
Methyl Acetate / 0.001 / 0.071 / 3.46E-13 / Oxygenated / Oxygenated
1-Decene / 0.000 / 0.000 / 4.61E-11 / Alkenes / Other
Propene / 0.000 / 0.133 / 1.02E-13 / Alkenes / Anthropogenic
Cyclopentanone / 0.000 / 0.003 / 2.94E-12 / Oxygenated / Oxygenated
Dichloromethane / 0.000 / 0.072 / 1.26E-13 / Halogenated / Other
Trichloroethene / 0.000 / 0.004 / 2.20E-12 / Halogenated / Other
Chlorobenzene / 0.000 / 0.013 / 5.50E-13 / Halogenated / Other
Ethylene oxide / 0.000 / 0.094 / 6.85E-14 / Oxygenated / Oxygenated
Chloroethane / 0.000 / 0.010 / 5.45E-13 / Halogenated / Other
Acetonitrile / 0.000 / 0.209 / 2.21E-14 / Nitriles and Sulfides / Other
Chloroform / 0.000 / 0.027 / 1.03E-13 / Halogenated / Other
1,2-Dichloroethane / 0.000 / 0.010 / 2.36E-13 / Halogenated / Other
Tetrachloroethene / 0.000 / 0.013 / 1.72E-13 / Halogenated / Other
tert-Butylbenzene / 0.000 / 0.000 / 4.85E-12 / Aromatics / Other
2,2-Dimethylpropane / 0.000 / 0.001 / 9.14E-13 / Alkanes / Other
1,4-Dichlorobenzene / 0.000 / 0.003 / 4.30E-13 / Halogenated / Other
2,2-Dimethylbutane / 0.000 / 0.011 / 8.93E-14 / Alkanes / Other
Bromomethane / 0.000 / 0.013 / 4.20E-14 / Halogenated / Other
t-2-Butene / 0.000 / 0.002 / 1.02E-13 / Alkenes / Other
c-2-Butene / 0.000 / 0.002 / 1.02E-13 / Alkenes / Other
1,1,1-Trichloroethane / 0.000 / 0.010 / 9.88E-15 / Halogenated / Other
Dibromomethane / 0.000 / 0.001 / 1.13E-13 / Halogenated / Other
Carbontretrachloride / 0.000 / 0.070 / 4.69E-16 / Halogenated / Other
3-Methyl-1-Butene / 0.000 / 0.002 / 1.09E-14 / Alkenes / Other
Indan (2,3-Dihydroindene) / 0.000 / 0.001 / 6.59E-15 / Aromatics / Other
Vinylchloride (Chloroethene) / 0.000 / 0.000 / 1.35E-16 / Halogenated / Other
Freon 22 (Chlorodifluoromethane) / 0.000 / 0.000 / 4.84E-15 / Halogenated / Other
Freon 12 (Dichlorodifluoromethane) / 0.000 / 0.000 / 7.50E-18 / Halogenated / Other
Freon 114 (1,2-Dichlorotetrafluoroethane) / 0.000 / 0.000 / 5.00E-16 / Halogenated / Other
Freon 11 (Trichlorofluoromethane) / 0.000 / 0.000 / 5.20E-18 / Halogenated / Other
Ethylbromide / 0.000 / 0.000 / 2.51E-13 / Halogenated / Other
1,1-Dichloroethene / 0.000 / 0.000 / 9.94E-12 / Halogenated / Other
Cyclopentene / 0.000 / 0.000 / 5.71E-11 / Alkenes / Other
t-1,2-Dichloroethene / 0.000 / 0.000 / 2.12E-12 / Halogenated / Other
4-Methyl-1-Pentene / 0.000 / 0.000 / 3.80E-11 / Alkenes / Other
3-Methyl-1-Pentene / 0.000 / 0.000 / 0.00E+00 / Alkenes / Other
1,1-Dichloroethane / 0.000 / 0.000 / 2.97E-13 / Halogenated / Other
Methyl-t-Butyl Ether ( MTBE ) / 0.000 / 0.000 / 3.11E-12 / Oxygenated / Anthropogenic
c-4-Methyl-2-Pentene / 0.000 / 0.000 / 6.09E-11 / Alkenes / Other
c-1,2-Dichloroethene / 0.000 / 0.000 / 2.74E-12 / Halogenated / Other
t-2-Hexene / 0.000 / 0.000 / 6.02E-11 / Alkenes / Other
2-Ethyl-1-Butene / 0.000 / 0.000 / 5.60E-11 / Alkenes / Other
t-3-Methyl-2-Pentene / 0.000 / 0.000 / 9.40E-11 / Alkenes / Other
c-2-Hexene / 0.000 / 0.000 / 6.19E-11 / Alkenes / Other
c-3-Methyl-2-Pentene / 0.000 / 0.000 / 9.40E-11 / Alkenes / Other
2,2-Dimethylpentane / 0.000 / 0.000 / 2.23E-12 / Alkanes / Other
2,2,3-Trimethylbutane / 0.000 / 0.000 / 8.39E-14 / Alkanes / Other
Cyclohexene / 0.000 / 0.000 / 6.18E-11 / Alkenes / Other
1,2-Dichloropropane / 0.000 / 0.000 / 4.64E-13 / Halogenated / Other
Bromodichloromethane / 0.000 / 0.000 / 2.66E-13 / Halogenated / Other
t-3-Heptene / 0.000 / 0.000 / 6.71E-11 / Alkenes / Other
c-3-Heptene / 0.000 / 0.000 / 6.59E-11 / Alkenes / Other
t-2-Heptene / 0.000 / 0.000 / 6.59E-11 / Alkenes / Other
c-2-Heptene / 0.000 / 0.000 / 6.59E-11 / Alkenes / Other
c-1,3-Dichloropropene / 0.000 / 0.000 / 8.45E-12 / Halogenated / Other
2,2-Dimethylhexane / 0.000 / 0.000 / 1.07E-12 / Alkanes / Other
t-1,3-Dichloropropene / 0.000 / 0.000 / 1.44E-11 / Halogenated / Other
1,1,2-Trichloroethane / 0.000 / 0.000 / 2.57E-13 / Halogenated / Other
1-Methylcyclohexene / 0.000 / 0.000 / 8.51E-11 / Alkenes / Other
Dibromochloromethane / 0.000 / 0.000 / 3.48E-13 / Halogenated / Other
1,2-Dibromoethane ( EDB ) / 0.000 / 0.000 / 2.66E-13 / Halogenated / Other
Bromoform / 0.000 / 0.000 / 1.50E-13 / Halogenated / Other
1,1,2,2-Tetrachloroethane / 0.000 / 0.000 / 2.46E-13 / Halogenated / Other
Benzyl Chloride / 0.000 / 0.000 / 2.81E-12 / Halogenated / Other
1,3-Dichlorobenzene / 0.000 / 0.000 / 7.21E-13 / Halogenated / Other
1,2-Dichlorobenzene / 0.000 / 0.000 / 4.20E-13 / Halogenated / Other
1,2,4-Trichlorobenzene / 0.000 / 0.000 / 5.99E-13 / Halogenated / Other
Propionaldehyde / 0.000 / 0.000 / 1.86E-11 / Oxygenated / Oxygenated
Propylene Oxide / 0.000 / 0.000 / 4.95E-13 / Oxygenated / Oxygenated
Acrylonitrile (2-Propennitrile) / 0.000 / 0.000 / 8.50E-12 / Nitriles and Sulfides / Other
Isopropylacetate / 0.000 / 0.000 / 3.91E-12 / Oxygenated / Oxygenated
3-Methyl-1-Butanol / 0.000 / 0.000 / 2.80E-12 / Oxygenated / Oxygenated
Isobutylacetate / 0.000 / 0.000 / 5.99E-12 / Oxygenated / Oxygenated