Chamber Simulation of Photooxidation of Dimethyl Sulfide

Chamber Simulation of Photooxidation of Dimethyl Sulﬁde and Isoprene in the Presence of NOx

Tianyi Chen and Myoseon Jang∗

Department of Environmental Engineering Sciences P.O. Box 116450, University of Flori- da, Gainesville, Florida 32611

Correspondence to: M. Jang (email: mjang@uﬂ.edu) Supplementary Materials

Number of Tables: 5 Number of Figures: 10

1 2

i i i The determination of kabs, kdes and kr In order to ﬁnd the rate determining step including partitioning processes and chemical reactions in gas phase, the characterization time of each step was analyzed. The characterization time (τ) to establish equilibrium (τeq) and τ of the gas phase reaction (τgas) of a compound with OH radicals are calculated using the equations below (Finlayson-Pitts and Pitts, 2000),

2 τeq = Dl(4HRT/αuav) eq. S1 where T is temperature, H is Henrys constant, α is accommodation coeﬃcient, and uav is mean thermal speed.

τgas = 1/(k[OH]) eq. S2 where k is the reaction rate constant in the gas phase and [OH] is the concentration of OH radical. For example, τeq of DMSO at the gas-liquid interface is in the order of 1 ∼ 10 s and much shorter than τgas of the gas phase reaction of DMSO, which is in 5 order of ∼ 10 s. Based on the short τeq, the equilibrium process governed by both the absorption of a compound onto a particle and its desorption from the particle should also be much faster than the reaction in the gas phase. Hence the determination of the i absolute values of kabs (absorption rate constant of a compound into the particle) and i kdes (desorption rate constant of a compound from the particle) becomes less important as long as, within computer process time, the characteristic times of both absorption i and desorption are much shorter than that of gas-phase reaction. In addition, the kabs i i i i and kdes values are constrained by kabs/ kdes = KP . In this study, the characteristic time for the absorption process is set to ∼ 10−4 s and applied to the estimation of both the adsorption and the desorption rate constants of the compounds of interest. The characteristic times of desorption of the three compounds of interest are in the order of ∼ 10−8 s. In order to conﬁrm the nature (surface reaction vs. bulk phase reaction) of the reaction of DMSO, DMSO2, and MSIA, the diﬀuso-reactive parameter, q is characterized using 3 the following equation (Finlayson-Pitts and Pitts, 2000): s k q = d r eq. S3 Dl

i where d is the particle radius (here assuming 50 nm), kr is the aqueous phase reaction rate constant and Dl is diffusion coefficient. In general, a high q value indicates that the reaction occurs on the surface. For all three compounds, q is smaller than 0.003 suggesting that their reactions are slow compared to diffusion so that reactions take place throughout the entire volume of the aerosol. The characterization of q value also implies that the gas-particle partitioning can be approached by the absorptive mode. 4

Artifacts of DMSO measurement in the presence of DMS The prediction of DMSO (not shown in the ﬁgures) is systematically much lower than the measured DMSO. However, as explained by Sorensen et al (1996), the fast reaction between DMSO and OH· should lead to the scavenging of the DMSO formed so the detected DMSO should be little. It is thus possible that the measurement of DMSO rather than the model prediction is problematic. It has been reported by Gershenzon

(2001) that DMS and O3 can rapidly react in the water with a reaction rate constant of ∼ 109 M−1 s−1 at room temperature, forming DMSO with a nearly unity yield. In 8 contrast, the liquid phase reaction between DMSO and O3 was found to be ∼ 10 times slower than that between DMS and O3, so once DMSO is formed as a product of DMS and O3 reaction, it will not be rapidly consumed by O3. It is thus reasonable to assume that the high concentration of DMSO measured in the presence of DMS was an artifact o due to the liquid-phase reaction of DMS and O3 collected in the liquid N2 trap (∼-195 C o o while the melting point of DMS is -98 C and that of O3 is -192 C). Rapid liquid phase reaction of DMS and O3 is most likely to occur when the cold trap is heated. In order to prove this hypothesis, 600 ppb DMS and 200 ppb O3 were injected into the chamber, then the chamber air was sampled using the liquid N2 trap. Since the rate of the reaction −20 3 −1 of DMS with O3 in gas phase is known to be in the order of ∼ 10 cm molecules s−1, there should be theoretically no or little DMSO detected. Nevertheless, with 10 ppb of DMS decay, 180 ppb of DMSO was detected, which demonstrated that the DMSO sampling method causes a significant amount of artifacts. As a result, measured DMSO concentrations in the experiments containing DMS were not used in this study. 5 Note a 2.90E-130 1.50E+071.20E-12 (Sander, 2006) 7.30E-13 (Veltwisch et al., 1980) (Yin et al., 1990) (Yin et al., 1990) 2.0E-12*EXP(440/TEMP)6.1E-12*EXP(800/TEMP) (Sander, 2006) (Sander, 2006) 1.00E-131.00E-131.00E-155.00E-12 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) . All the rate constants other than those given using an 3 cm 1 − molecules 1 − 2 H 2.00E-13 (Yin et al., 1990) 3 2 + NO -SO · O 1.00E-14 (Yin et al., 1990) 3 -OOH 1.00E-15 (Yin et al., 1990) 2 -OH 1.00E-13 (Yin et al., 1990) 3 O 3 · 3 2 3 + HO 3 2 DMSO photooxidation mechanisms 3 + H · · OO · + CH O 3 2 · 3 2 3 O 1.16E-10 (Kukui et al., 2003) 2 + CH · 2 + CH · + HNO + H + OH · · · + H + CH · (O)S(O)CH · (O)S(O)CH (O)S(O)CH 3 3 (O)S(O) 3 3 3 (O)S(O) (O)S(O)CH Table S1. (O)S(O) 3 3 (O)S(O)CH 3 (O)S(O)CH CH 3 CH 3 + CH + CH -S(OH)(O)CH (O)S(O) (O)S(O) (O)S(O) CH CH 2 (O)S(O) 2 3 3 3 3 → CH -S(O)OH+ CH 3 CH 3 CH · → → reactions) SO NO+ CH NO CH CH CH 3 CH · → 2 → CH and the unit for second order reactions is s → 4 · → 2 CH 1 → 2 → → reactions → → → + NO -O -O -SO − → · · → → · 2 3 3 2 3 3 3 P + O P reactions 3 3 3 3 + O 3 + OH · OO and its further reactions 3 2 2 OO. + O + OH 2 + NO + NO 3 3 3 3 3 -S(O)CH -S(OH)(O)CH -S(OH)(O)CH (O)S(O)CH (O)S(O)CH -S(O)OH + OH -S(O)CH -S(O)CH -S(O)CH -S(O)OH + CH -S(O)OH + O -S(O)OH + NO -S(O)OH + HO -S(O)OH + CH (O)S(O)CH -S(O)OH + CH 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Reactions (see CH -S(OH)(O)CH (O)S(O)CH · S(O)OH (O)S(O)CH 3 3 DMSO Reactions Rate constant 3 3 3 4Primary products a. CH CH b. CH 56c. CH CH 7 CH 8Secondary CH Products a. CH CH 9 CH Initial reactions 123 CH CH CH 1112 CH 13 CH 14 CH 15 CH b. CH CH 16 CH 10 CH The unit for first order reactions is s a Arrhenius expression are for 298 K and 1 atm. 6 1.00E-11 (Yin et al., 1990) 2.50E-134.20E-117.50E-12 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) 1.00E-14 (Yin et al., 1990) 8.60E-145.00E-15 (Yin et al., 1990) 1.00E+012.60E-183.30 (Yin et al., 1990) (Mellouki et al., 1988) (Yin et al., 1990) (Yin et al., 1990) 5.00E-114.00E-122.50E-131.50E-12 (Kukui et al., 2003) (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) 2 · · 3 + O · -O. 1.80E-13 (Yin et al., 1990) -SO O 3 3 2 · (O)S(O) 3 -SO + CH + CH 3 2 · 2 Cont’d. O 2 + CH + O · · (O)S(O)CH + CH · O · 3 O 3 2 2 O 2 OOH+ O 2CH 2 -SO + NO 6.80E-13 (Yin et al., 1990) 3 · 3 Table S1. (O)S(O)CH -O 3 · → 3 3 2 + CH · OO CH (O)S(O)CH (O)S(O)CH 2 3 3 (O)S(O)CH 2 · 2 + CH 3 · -SO (O)S(O)CH + NO + H-CO-H 1.00E+01 (Yin et al., 1990) · → 2 3 CH 3 CH 3 · · (O)S(O)CH 3 CH 3 + OH 2.50E-13 (Yin et al., 1990) + O + NO 5.00E-13 Estimate · · CH H 5.00E-11 (Yin et al., 1990) + NO CH -SO 3 · 3 + O · → 3 · → · 3 -SO (O)S(O)S-CH CH 2 3 · → 3 3 · → -SO -SO -SO · → -SO (O)S(O) -O (O)S(O)CH -S CH -SO 2 (O)S(O) 3 3 3 2 3 3 3 3 3 3 (O)S(O)OO -SO CH CH · → 3 3 3 (O)S(O) CH CH CH 3 · → CH → CH 2 CH CH · → + SO · + CH + CH + HO + CH + CH + CH → → → · · · · · · CH 3 -S (O)S(O) -S-NO -O · → 2 3 2 → → 3 3 3 3 reactions · → 2 3 · O OO OO OO OO OO OO CH + NO · · → 2 2 2 2 2 2 2 O 2 + OH + CH + CH + CH + CH + HO + O + NO + NO + O · · · · · · → · · · · · (O)S(O)OO (O)S(O) (O)S(O) (O)S(O) (O)S(O) (O)S(O) (O)S(O) (O)S(O)CH (O)S(O) (O)S(O) (O)S(O)OO (O)S(O) (O)S(O) (O)S(O) (O)S(O)CH (O)S(O)CH (O)S(O)CH (O)S(O)CH (O)S(O)CH (O)S(O)CH 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 (O)S(O) reactions (O)S(O)CH (O)S(O)OO reactions 3 3 3 c. CH 36 CH 35 CH 3233 CH 34 CH CH 31 CH 27 CH Tertiary and further products a. CH 23 CH 26 CH 2829 CH 30 CH CH b. CH 2425 CH CH 1819 CH 20 CH 21 CH 22 CH CH 17 CH 7 1.00E-124.20E-03 (Yin et al., 1990) (Yin et al., 1990) 6.00E-118.00E-123.00E-13 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) 2.00E-125.50E-12 (Yin et al., 1990) (Yin et al., 1990) 1.00E-156.00E-057.00E-05 (Yin et al., 1990) Experiment Experiment 6.00E-12 (Yin et3.00E-16 al., 1990) 1.00E-163.00E-15 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) 4.00E-023.00E-16 Estimate (Yin et al., 1990) 5.00E-116.60E-16 (Yin et al., 1990) (Yin et al., 1990) 2 + O · 3 -SO. 4.00E-13 (Yin et al., 1990) Cont’d. 3 · -SO 3 · 2 2 + CH · 2 · 2 CH + O · 3 · (O)S(O) 2 2 3 · 2 -O Table S1. -SO + O 3 · → 3 · 3 -O 3 + CO 1.60E-15 (Yin et al., 1990) · -SO -SO 2 + CH 3 + NO 3 · · 2 + CH · 3 + CH · 3 2 H + HNO H + HONO 1.00E-15 (Yin et al., 1990) 2 3 (O)S(O)OOH 3 3 3 2 2 CH -SO H + CH + CH -SO 3 · 3 3 -SO -SO H + H-CO-H + HO -SO CH H + HO 3 3 3 3 3 (O)S(O)OOH H + NO · → (O)S(O)OONO CH 3 3 CH 3 -SO → H + HO CH 3 CH H + O 3 CH -SO (O)S(O)OO -SO 3 CH → 3 3 3 CH · → -SO → CH → 3 2 -SO · → (O)S(O)ONO -SO 3 CH CH → CH · O O · → 3 3 -S -SO (O)S(O) -O -S-OH → 3 (O)S(O)ONO 3.00E-15 (Yin et al., 1990) 2 CH (O)S(O)OO 2 2 2 3 3 3 3 3 3 3 → → CH → CH CH → 2 CH + H → 2 → + CH → → + NO + CH + CH + CH + HO + CH +CH + CH 2 -OH -OOH 3 · · · · · · · · 3 → 2 2 3 3 O → 2 SO 3 + CH + NO + H-CO-H + CH + HO + HONO + H + NO · · · → · · · · · 3 3 3 3 3 3 3 3 3 reactions · 3 (O)S(O)OO (O)S(O)OONO (O)S(O)OO (O)S(O)OO (O)S(O)OO (O)S(O)OO (O)S(O)OO (O)S(O)OO -SO (O)S(O)CH -S(O)CH (O)S(O)ONO + H (O)S(O)OO -SO -SO (O)S(O)ONO -SO -SO -SO -SO -SO -SO 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 -SO 3 3738 CH 39 CH CH 4041 CH 42 CH CH 4344 CH CH 55 CH 58 CH Wall loss 57 CH 56 CH 45 CH 5253 CH 54 CH CH d. CH 46 CH 47 CH 51 CH 48 CH 4950 CH CH 8 Note tanovic et al., 1981; Nip1981) et al., al., 1981) a . All the rate constants other than those given using an 3 cm 1 − 1.4E-13*EXP(500/TEMP) (Atkinson et1.30E-12 al., 1989; Nip5.00E+05 et 1.00E-127.30E-13 (Barone et al., (Yin 1996) et al., 1990) (Yin et al., 1990) (Schafer et al., 1978) 1.00E+02 (Yin et al., 1990) 5E-11*EXP(0.0409/TEMP) (Atkinson et al., 1989; Cve- 1.90E-118.60E-14 (Nielsen et al., 1995) (Wallington et al., 1986) 6.10E-11 (Yin et al., 1990) 4.00E-122.50E-13 (Yin et al., 1990) (Yin et al., 1990) 1.80E-13 (Yin et al., 1990) molecules 1 − · DMS photooxidation mechanisms 2 O + + + 2 · · · -S- -S- · 3 3 2 O O O 2 3 2 2 2 + M 1.70E-12 (Atkinson et al., 1989) CH 3 SCH 3 2CH 3 + NO 3 O 1.13E-11*EXP(-254/TEMP) (Atkinson et al., 1997) · + HO + NO 3.00E-10 (Sander, 2006) -OOH 5.00E-12 (Nielsen et al., 1995) 2 Table S2. -S-CH -S-CH -S-CH · · 3 2 · O 3 3 3 3 · 3 2 + NO 9.00E-21 (Balla and Heicklen, 1984) )CH · → 3 + H 2 + HNO -OO CH CH CH · · · → 2 2 2 -OO -S-CH -S(OH)CH + CH 2 -OO 3 · 3 -S-CH 2 3 -S(OH)(OO)CH -S(O)CH and the unit for second order reactions is s 3 3 · → CH · → CH -SO 1 -S-CH -S-CH -S-CH 2 · → -S(ONO -S(O)CH 3 CH 3 − 3 3 3 3 -S-CH (O)S(O) CH CH -S 3 → 3 -O -SO -S-CH -S-OH + CH 3 · → → 3 3 3 3 CH CH CH CH 2 CH CH → → CH 2 2 → → → → CH → · · → 3 2 3 → 3 P 3 → 3 2 + NO + CH + HO + CH + CH + CH + CH + O + O · · · · · · · 3 3 3 -SO )CH . · 3 2 + OH + NO + NO + OH + M + O + O + NO 2 · · -OO -OO -OO -OO -OO -OO -OO 2 2 2 3 3 3 2 3 2 2 2 3 2 2 2 · + O · + O + CH · · -S(OH)CH -S(OH)CH -S-CH -S-CH -S-CH -S-CH -S-CH -S(OH)CH -S(ONO -S-CH -S-CH -S-CH O -S-CH -S-CH -S-CH -SO -S-CH (O)S(O) -S-CH O -S-CH -O 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 3 3 3 3 3 2 3 3 DMS Reaction Rate constant CH CH CH CH CH 65 CH 66 CH 67 CH 68 CH 69 CH Initial reactions 59 CH 62 CH 63 CH Primary products 64 CH Secondary products a. DMSO b. Methylthiomethylperoxyl radical70 CH CH 60 CH 73 CH 71 CH 72 CH 61 CH 74 CH 75 CH 76 CH The unit for first order reactions is s a Arrhenius expression are for 298 K and 1 atm. 9 5.00E-12 (Yin et al., 1990) 1.00E+01 (Yin et al., 1990) 8.50E-13 (Yin et al., 1990) 3.40E-12 (Yin et al., 1990) 5.80E-176.00E+025.70E-12 (Sander, 2006) (Yin et al., 1990) (Domine et al., 1992) Cont’d. 2 + M 9.20E-12 (Nielsen et al., 1995) · Table S2. + NO 2 3 O 3.60E-18 (Yin et al., 1990) 2 H 3.40E-12 (Yin et al., 1990) 3 · 2 + H -OONO · -SO 2 3 3 -OOH 8.50E-13 (Yin et al., 1990) -OH3 3.40E-12 (Yin et al., 1990) 3 + HO 3 3 2 -S-CH + CH O -S(OH)(O)CH · O 1.10E-10 (Yin et al., 1990) 3 2 3 + CH · 2 + CH · CH -SO CH -S-S(O)CH + HNO + H + OH 3.40E-12 (Yin et al., 1990) 3 -SO · · · 3 + H -SO 3 · -S(O)CH 2 → → 3 3 CH CH -SO -SO -SO CH · -SO 2 3 3 3 CH CH + O + H-CO-H 2.00E+01 (Yin et al., 1990) 3 · · → + M 3 · → → 2 3 CH CH CH -S + NO · → (DMSO reactions) + O CH 3 3 3 · → 2 · -SOO -SO 3 3 3 and its further reactions → → → -S -SO -O -O → CH 3 )-CH 3 2 3 3 3 3 · -S-OH P )CH )CH + NO · · CH CH · 3 3 CH · · → → → O -OO O 2 3 2 2 2 · → reactions + O + O · · · -S-OH + OH -S-OH + CH -S(OH)(OO -S-OH + CH -S-CH -S(OH)(OO -S-OH + O -S-OH + NO -S-OH + CH -S-OH+CH -S-OH + HO -S-CH -S -SOO -S -S-OH (O)S(O)CH -S-CH S(O)OH -S -S(OH)(OO -S(OH)(O)CH 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 ( DMSO reactions) (DMSO reactions) d. CH 80 CH 81 CH 82 CH 79 CH 77 CH c. CH 78 CH 83 CH 84 CH 86 CH 87 CH d. CH Tertiary products a. CH b. CH Further products a. CH 89 CH 85 CH 88 CH c. CH 90 CH 91 CH 10 P] (Yin et al., 1990) 3 O to 2 1.10E-118.00E-119.00E-123.00E-134.00E-126.00E-12 (Turnipseed et al., 1992) (Yin et al., 1990) 7.70E-18 (Yin et al., 1990) 1.70E+02 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) (Yin et al., (Yin 1990) et al., 1990) 8.00E-12 Estimate 5.50E-12 (Yin et al., 1990) 3.00E-12 MCM v3.2 5.70E-12 (Domine et al., 1992) 6.10E-13 (Yin et al., 1990) 2.87E-11 (Balla et al., 1986) 6.40E-11 (Yin et al., 1990) 6.10E-11 (Yin et al., 1990) 4.15E-11 (Graham et al., 1964) Cont’d. · + SO Table S2. 3 · · 3 2 -SO + O 3 · 2 (O)S(O) -O -S(O)CH 3 3 3 · +CH 2 · + NO 1.40E-12 (Yin et al., 1990) +O · 3 -O 2 3 2 +CH -SO + CH + CH 3 · -SO · 3 2 · + NO 3.00E-12 MCM v3.2 3 3 · · CH CH 2 + CH -SO -SO · · -SO + NO 3 · -S-S-CH 3 · 2 3 → 3 · 2 CH + NO + OH 3.00E-11 (Yin et al., 1990) + NO 0.5*j[NO ) + NO 6.10E-11 (Yin et al., 1990) · · · -O -SOOH + O · · → + O -SO 2 CH CH 3 3 · -SO 3 -S-S-CH + NO + SO CH -S (O)S(O) · 2CH 3 3 3 · → 3 3 -SO -SO -S(O)OO -S-NO -SO CH 3 3 -S-OH 5.00E-11 (Yin et al., 1990) -SO CH · → +(O -S-NO 3 3 3 · → 3 3 CH CH · → 3 CH 2 · → CH CH + CH 3 2 CH CH → CH CH CH · → -S -SO (O)S(O) -O -SOO → CH CH → CH 2 → → 2 3 3 3 3 3 · → SO υ 2 2 → → → · → · → -O -S -S-NO → · → -S-CH 2 2 2 3 2 · → 3 3 3 → 3 + h 3 · + CH + CH + CH + HO + CH + NO + CH · · · · · · · reactions + O + NO + NO · · · · reactions + NO + NO + NO + NO + HO + CH + CH + OH + CH · · · · · · · · · · -SOO -SOO -SOO -SOO -SOO -SO -S(O)OO -SO -SOO -SOO -SO -S+ CH -S+ O -S -S -S -S -S -S -S -S -S -S-NO 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 SOO SO 3 3 92 CH 93 CH 94 CH 95 CH 96 CH 9798 CH CH 99 CH 111 CH 105 CH 106 CH 107 CH 108 CH 109 CH c. CH 112 CH 113 CH 114 CH b. CH 104 CH 110 CH 103 CH 102 CH 100 CH 101 CH 11 (Yin et al., 1990) 8.00E-12 (Yin et al., 1990) 6.00E-12 (Yin et al., 1990) 2.66E32*EXP(- 25200/TEMP) 1.00E-12 (Tyndall and Ravishankara, 1989) 3.00E-135.50E-121.00E-124.20E-03 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) 7.00E-118.10E-12 (Yin et al., 1990) (Yin et al., 1990) 7.50E-123.00E-123.20E-138.00E-12 (Yin et al., 1990) (Yin et al., 1990) (Borissenko et al., 2003) (Yin et al., 1990) 6.80E-13 (Yin et al., 1990) 1.00 (Yin et al., 1990) Cont’d. 3 2 -SO · 2 +O 3 2 · · Table S2. -O + O 3 -SO · 3 -S-CH · · 3 -O 2 + NO 6.80E-13 (Yin et al., 1990) · · 3 + CH 2 2 · 3 + CH · 2 (O)S(O) 3 (O)S(O)+ CH + NO (O)S(O) 3 H + CH · + CH 3 · + NO 3 2 · (O)S(O) 2CH CH 3 2 + NO (O)S(O) · + OH 1.50E-12 (Yin et al., 1990) 3 · -SO (O)S(O) 2 + O +CH 3 3 -S-S(O)CH · · 3 · → · → -S(O)OONO 2CH CH -O -S (O)S(O) 3 3 CH + NO (O)S(O) CH 3 3 · 3 CH -S(O)OO 3 CH · → · → → (O)S(O) CH CH (O)S(O) 2 3 -SO CH · · → -S(O)OH 5.00E-11 (Yin et al., 1990) 3 3 (O)S(O) 3 3 · → 3 + CH → CH 3 -O -SO (O)S(O) -S → → 2 -S(O)OO CH 2 → 3 3 3 3 CH 3 CH → CH 2 CH SO reactions 2 -S-CH → + CH · → -SO. 3 -O -S-NO → · · 3 2 → → 3 3 3 reactions (DMSO reactions) · → reactions + NO + CH +CH + CH + CH + NO + CH and its futher reactions · · · · · · · 2 3 3 · · SO · 2 reactions + CH · 2 reactions + O + NO + HO + CH + CH + CH + OH + O · · · · → · 3 · · · · 3 -SO -S(O)OO -SO -SO -S(O)OO -S(O)OO -S(O)OONO -SO -SO -S(O)OO -S(O)OO -SO -SO -SO -S(O)OO -S(O)OO -S(O)NO -SO -SO 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 (O)S(O) -SO -S(O)OO reactions (O)S(O)OO 3 SONO 3 3 3 -S(O)CH · 3 ( DMSO reactions) 3 3 117 CH 130 CH 116 CH 118 CH 128 CH 129 CH 131 CH f. CH g. CH 119 CH 132 CH 115 CH 126 CH 127 CH 120 CH 121 CH d. CH e. CH 124 CH 125 CH h.CH 133 CH i.CH Table S2 (cont’d) j.CH 122 CH 123 CH 12 (Atkinson et al., 1989) (Atkinson et al., 1989;et Cvetanovic al., 1981; Nip et al., 1981) P] (Yin et al., 1990) 3 O to 2 8.60E-14 (Yin et al., 1990) 1.80E-135.62E- (Yin et11*EXP(250/TMEP) al., 1990) 5.59E- 11*EXP(380/TMEP) 7.00E-131.00E+025.0E-3*j[NO (Yin et al., (Yin 1990) et al., 1990) 2.50E-13 (Yin et al., 1990) 4.00E-12 (Yin et al., 1990) 1.00E-126.00E-125.00E-11 (Yin et al., 1990) (Yin et al., 1990) (Yin et al., 1990) 9.00E-069.00E-06 Experiment Estimated · · · · O O 2 O O 2 Cont’d. 2 2 · O 2 -S(O)CH -S(O)CH 3 -S(O)CH -S(O)CH 3 3 3 2 Table S2. OOH 1.50E-12 (Yin et al., 1990) · + CH 2 -S(O)CH · + CH -S 3 · 3 + CH + 2CH · 3 + NO 2 · · 3 O -O O -SO -S · 3 · 2 3 3 + CH -S · + CH · 3 -S(O)CH · → OO CH 2 3 (O)S(O) )S-CH 2 3 2 -SO + CH OO 3 2 2 · → CH O + CH -S(O)CH · + CH CH 3 2 · + H-CO-H 1.00E+02 (Yin et al., 1990) O · → · → -S(O)NO -S(ONO -S -SO · -S(O)CH CH -S-OH + CH 2 3 3 3 3 · → 3 3 → + H-CO-H 1.00E+03 (Yin et al., 1990) -S(O)CH -O (O)S(O) -S -SO → · -SO CH 2 3 3 3 3 3 CH CH CH CH 3 -S 2 CH 3 → → → → CH 3 · → 3 → 2 P CH + CH + CH + HO + CH + NO + CH + CH S(O)OH reactions (DMSO reactions) · 3 · · · · · · υ 3 · → + O O OO OO OO OO OO OO OO · → · → reactions + OH + O + NO )S-CH + h 2 2 2 2 2 2 2 2 2 2 3 3 3 2 3 3 → 3 3 -S(O)CH -S(O)CH -S-S-CH -S-S-CH -S-S-CH -S(O)CH -S(ONO -S-S-CH -S(O)CH -S(O)CH -S(O)CH -S(O)CH -S(O)CH -S-CH -S-S-CH -S(O)CH -S(O)CH 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 -S-S-CH 3 S-OH and CH 3 143 CH l.CH m.CH 142 CH 144 CH 145 CH 146 CH 141 CH 147 CH 148 CH 140 CH 139 CH 136 CH 137 CH 138 CH wall loss 149 CH 150 CH 134 CH 135 CH 13 Note and Lloyd, 1984) and Lloyd, 1984) a P] (Graedel, 1977) 3 O . All the rate constants other than those expressed using 3 to 2 cm 1 − 1.10E-144.00E-13 (Graedel, 1977) (Atkinson et al., 1989; Kerr, 1984) 6.30E-13 (Graedel, 1977) 2*j[NO 3.70E+06 (Graedel, 1977) 2.90E-137.00E-21 (Graedel, 1977) (Sander, 2006) 1.00E-185.00E-175.50E-132.00E-26 (Atkinson et al., 1989; Atkinson (Atkinson et al., 1989; Atkinson (Calvert, 1984) (Sander, 2006) 9.75E-13*EXP(-1000/TMEP) (Baulch et al., 1984; Kerr, 1984) 9.07E-13exp (231/TMEP) (Atkinson et al., 1989; Kerr, 1984) 4.51E-12*EXP(-1170/TMEP)2.20E-111.10E-10 (Atkinson et2.00E-15 al., 1989) (Graedel, 1977) (Graedel, 1977) (Graedel, 1977) 1.39E-13*EXP(-2280/TMEP) (Atkinson et al., 1989) molecules 1 − photooxidation mechanisms 2 SO Table S3. · -O · + M 1.00E-11 (Graedel, 1979) 3 2 4 · 3 SO and the unit for second order reactions is s 2 · 3 2 2 · 1 3 + CH 2 H -O-SO − P 3 3 + SO 2 3 2 2 (O)S(O) → SO + NO + OH 3 + NO 1.40E-11 (Atkinson et al., 1989) + HO 2 2 CH 3 3 3 2 2 + O + O HO ∗ 2 → 2 2 CH SO → SO SO NO + SO SO HOSO SO SO+ SO + M 2 SO 2SO SO+ CO · → 2 SO SO SO → 2 → → → → → → → · → 2 2 2 2 2 · → 2 · → → 2 2 · → + SO · → · → · υ + O + OH + SO SO 2 · 2 2 + SO Reactions Rate constant + SO + SO + SO + SO -O -O · + SO + CO + SO → + h + SO 3 2 2 · 2 3 3 3 ∗ 2 ∗ 2 2 ∗ 2 3 2 P+ SO P + SO + SO + SO 3 3 3 2 SO reactions reactions reactions ∗ 2 2 · 169170 HOSO HOSO 168 SO 167 SO 162 SO SO 166 SO 159 CH 160161 CH CH 165 NO 158 HO 164 NO 157 O 154155 O 156 OHSO + SO SO 163 OH 152153 NO O SO 151 O The unit for first order reactions is s a an Arrhenius equation are based on 298 K and 1 atm 14 7.00E-06 Experiment 7.00E-13 (Calvert et al., 1978) Cont’d. Table S3. + M 9.10E-13 (Atkinson and Lloyd, 1984; Kerr, 1984) 4 2 SO 2 + O H 2 → SO → P) O + M 3 2 → + H + O( 2 3 3 reactions 3 wall loss 173 SO 171 SO SO 172 SO 15

Table S4. Comparison of the wall loss rates of diﬀerent chemicals in this study and those in literature

wall loss rate chemical in this study in literature DMS 9.0×10−6 1.5×10−6 (Yin et al., 1990) −5 −6 SO2 2.0×10 2.2×10 (Yin et al., 1990) −5 −6 O3 2.5×10 4.5×10 (Yin et al., 1990) DMSO 6.0×10−5 3.3×10−5(Ballesteros et al., 2002) −5 −5 DMSO2 7.0×10 4.4×10 (Ballesteros et al., 2002) −4 −4 H2O2 6.7×10 2.4×10 (Qi et al., 2007) 16

Table S5. Integrated reaction rate (IRR) of the initial reactions of DMS decay normalized by ∆DMS in diﬀerent conditions a

No.b Reaction iso-DMS-1 iso-DMS-2 iso-DMS-3 59 CH3-S-CH3 + OH· 0.275 0.229 0.283 60 CH3-S-CH3 + OH· 0.097 0.081 0.098 3 61 CH3-S-CH3 + O( P) 0.184 0.275 0.393 62 CH3-S-CH3 + NO3· 0.123 0.197 0.158 63 CH3-S-CH3 + NO2 0.002 0.002 0.002 103 CH3-S·+ CH3-S-CH3 0.148 0.164 0.228 132 CH3-S-CH3 + CH3-SO3· 0.084 0.090 0.087 aRefer to Table 3 for the experimental conditions. bRefer to Table S2 for the reaction number 17

Figure S1. Mass fragmentation spectra in the EI mode (with GC retention time) for d6-DMSO, DMSO and DMSO2 18

Figure S2. Time proﬁles of DMSO, DMSO2, SO2, NOx and O3 for the photooxidation of DMSO in the presence of NOx (Exp DMSO-3, Exp DMSO-4 and Exp DMSO-5 in Table 1). “E” denotes the experimentally observed concentrations of chemical species and “S” for those simulated using the kinetic model. 19

Figure S3. Model simulation of MSA and sulfuric acid for the photooxidation of DMSO in the presence of NOx (Exp DMSO-3, Exp DMSO-4 and Exp DMSO- 5 in Table 1) with (SH) and without (SN) including heterogeneous reactionS “E” denotes the experimentally observed concentrations of chemical species and “S” for those simulated using the kinetic model. 20

Figure S4. Time proﬁles of DMS, DMSO2, SO2, MSA, sulfuric acid, NOx and O3 for the photooxidation of DMSO in the presence of NOx (Exp DMS-1 and Exp DMS-2 in Table 1). “E” denotes the experimentally observed concentrations of chemical species and “S” for those simulated using the kinetic model. 21

Figure S5. Mass fragmentation spectra in the EI mode (with GC retention time) for PFBHA derivatives of major carbonyl products originated from isoprene photooxidation in the presence of NOx. P1: methacrolein (mono- derivatives), P2: methyl vinyl ketone (mono-derivatives), P3: glyoxal (di- derivatives), P4: methylglyoxal (di-derivatives) 22

Figure S6. Time proﬁles of isoprene, P1–P4, NOx and O3 from the photooxidation of isoprene in the presence of NOx (Exp iso-1 and Exp iso-2 in Table 2). “E” denotes the experimentally observed concentrations of chemical species and “S” for those simulated using the kinetic model. 23

Figure S7. Time proﬁles of gaseous products (P1–P4), NOx and O3 from the photooxidation of DMS and NOx in the presence of 560 ppb of isoprene (Exp iso-DMS-1), 1360 ppb of isoprene (Exp iso-DMS-2) and 2248 ppb of isoprene (Exp iso-DMS-3). “E” denotes the experimentally observed concentrations of chemical species and “S” for those simulated using the kinetic model. 24

Figure S8. The proﬁles of the yields of MSA and H2SO4 in the low concentration of DMS (0.5 ppb) with diﬀerent amount of initial NOx concentrations (50 ppb and 2 ppb) against the consumed amount of DMS using the kinetic model. 25

Figure S9. The proﬁles of the yields of MSA (A) and H2SO4 (B) in the low concentration of DMS (0.5 ppb) and NOx (2 ppb)with diﬀerent initial isoprene concentrations (0 ppb, 0.5 ppb and 2.5 ppb) against the consumed amount of DMS using the kinetic model. 26

Figure S10. Time proﬁles of the concentrations of MSA (A) and H2SO4 (B) in the low concentration of DMS (0.5 ppb) with diﬀerent amount of initial NOx concentrations (50 ppb and 2 ppb) using the kinetic model with and without including 4 µg/m3 of initial seed. 27

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