Experimental and theoretical studies on gas-phase reactions of NO3 radicals with three methoxyphenols: Guaiacol, creosol, and syringol

Abstract

h i g h l i g h t s• Reaction products of NO 3 radical with three methoxyphenols are obtained.• Nitro-substituted derivatives are observed as major transformation products.• Reaction mechanisms of methoxyphenols with NO 3 radicals are proposed.• The rate constants of three methoxyphenols with NO 3 radicals are measured. a b s t r a c t Methoxyphenols, lignin pyrolysis products, are major biomass combustion components and are considered potential tracers for wood smoke emissions. Their atmospheric reactivity, however, has not been well characterized. Guaiacol, creosol, and syringol are three typical methoxyphenols generated in relatively high concentrations in fresh wood smoke. In this study, the gas-phase reactions of NO 3 radicals with these methoxyphenols were investigated using a laboratory-built vacuum ultraviolet photoionization gas time-of-flight mass spectrometer (VUV-GTOFMS) and off-line GC-MS. By combining experimental and theoretical methods, 4-nitroguaiacol, 6-nitroguaiacol, and 4,6-dinitroguaiacol were determined as the primary degradation products for guaiacol; similarly, 6-nitrocreosol and 3-nitrosyringol were identified for creosol and syringol, respectively. Using the relative rate method, rate constants at 298 K and 1 atm for the gas-phase reactions of guaiacol, creosol, and syringol with NO 3 radicals were measured to be 3.2 × 10 −12 , 2.4 × 10 −13 , and 4.0 × 10 −13 cm 3 molecule −1 s −1 , respectively. At a typical tropospheric concentration of NO 3 radicals (5 × 10 8 molecule cm −3 ), atmospheric lifetimes for guaiacol, creosol, and syringol toward NO 3 radicals were 0.2, 2.3, and 1.4 h, respectively. These results indicate that the reaction with NO 3 radicals can be a major sink for methoxyphenols at night. a r t i c l e i n f o

Rate constant and secondary organic aerosol formation from the gas-phase reaction of eugenol with hydroxyl radicals

“…In addition, methoxyphenols are the major component of OA from biomass burning (Bruns et al, 2016;Schauer and Cass, 2000). Based on our results and those of previous studies (Sun et al, 2010;Lauraguais et al, 2012Lauraguais et al, , 2014bAhmad et al, 2017;Yee et al, 2013;Ofner et al, 2011), more attention should be paid to SOA formation from the OH oxidation of biomass burning emissions and its subsequent effect on haze evolution, especially in China with nationwide biomass burning and high daytime average [OH] in the ambient atmosphere (5.2 − 7.5 × 10 6 molecules cm −3 ) (Yang et al, 2017). Meanwhile, the potential contributions of SO 2 and NO 2 to SOA formation should also be taken into account because the concentrations of NO x and SO 2 could be up to 200 ppbv in the severely polluted atmosphere in China .…”

Snow scavenging and phase partitioning of nitrated and oxygenated aromatic hydrocarbons in polluted and remote environments in central Europe and the European Arctic

“…The dissolved phase concentrations of 4-NG in samples from urban and rural environments were comparable (~ 155-285 ng L -1 ; Fig. 2A-B), indicating polluted and aged air masses with biomass burning origin (Kitanovski et al, 2014;10 Kroflič et al, 2015;Yang et al, 2016). These values are one order of magnitude higher than the measured concentration for the Arctic sample Rm1 (Fig.…”

Enhancement of Secondary Organic Aerosol Formation and its Oxidation State by SO<sub>2</sub> during Photooxidation of 2-Methoxyphenol

“…Biomass burning is considered as one of the major sources of gas and particulate pollutants in the atmosphere (Lauraguais et al, 2014b;Yang et al, 2016). Therefore, it has significant adverse impacts on regional and global air quality (Bari and Kindzierski, 2016;Lelieveld et al, 2001), climate (Chen and Bond, 2010), and human health (Naeher et al, 2007).…”

“…Its emission factor of wood burning is in the range of 172−279 mg kg -1 fuel (Schauer et al, 2001). In recent years, the reactivity of gas-phase guaiacol toward OH radicals (Coeur-Tourneur et al, 2010a), NO3 radicals (Lauraguais et al, 2016;Yang et al, 2016), chlorine atom (Lauraguais et al, 2014a), and O3 (El Zein et al, 2015) has been investigated, suggesting that its degradation by OH radicals and NO3 radicals might be predominant Atmos. Chem.…”