Secondary organic aerosol formation from biomass burning intermediates: phenol and methoxyphenols

Abstract

The formation of secondary organic aerosol from oxidation of phenol, guaiacol (2-methoxyphenol), and syringol (2,6-dimethoxyphenol), major components of biomass burning, is described. Photooxidation experiments were conducted in the Caltech laboratory chambers under low-NO<sub>x</sub> (<10 ppb) conditions using H<sub>2</sub>O<sub>2</sub> as the OH source. Secondary organic aerosol (SOA) yields (ratio of mass of SOA formed to mass of primary organic reacted) greater than 25% are observed. Aerosol growth is rapid and linear with the primary organic conversion, consistent with the formation of essentially non-volatile products. Gas- and aerosol-phase oxidation products from the guaiacol system provide insight into the chemical mechanisms responsible for SOA formation. Syringol SOA yields are lower than those of phenol and guaiacol, likely due to novel methoxy group chemistry that leads to early fragmentation in the gas-phase photooxidation. Atomic oxygen to carbon (O:C) ratios calculated from high-resolution-time-of-flight Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS) measurements of the SOA in all three systems are ~0.9, which represent among the highest such ratios achieved in laboratory chamber experiments and are similar to that of aged atmospheric organic aerosol. The global contribution of SOA from intermediate volatility and semivolatile organic compounds has been shown to be substantial (Pye and Seinfeld, 2010). An approach to representing SOA formation from biomass burning emissions in atmospheric models could involve one or more surrogate species for which aerosol formation under well-controlled conditions has been quantified. The present work provides data for such an approach

Effect of phenolic compounds on photodegradation of anthracene and benzo[a]anthracene in media of different polarity

“…The same reactivity order was also reported in toluene by McDow et al [13] and Yee et al [42]. In general, 2,6-DMP is more reactive than 2-MP because of its additional methoxyl group, and 2,6-DMP can be converted to 2-MP during the transport of biomass burning emissions in the atmosphere [42]. However, a different reactivity order was observed in methanol as well as in water, probably due to the different interaction between phenolic compounds and solvent molecules.…”

“…Trace amounts of H 2 O 2 were suggested to be generated in the direct photolysis of vanillin in aqueous phase and then form OH radicals to react with vanillin [41]. The phenolic proton is readily abstracted by OH radical followed by the production of carbon centered radicals ortho and para to the site of abstraction; and eventually the formation of higher molecular weight oligomers [42].…”

Reaction Kinetics of Catechol (1,2-Benzenediol) and Guaiacol (2-Methoxyphenol) with Ozone

“…In the literature, rate coefficients, have been reported for the reaction of catechol with OH 10,14 , NO 3 8 and O 3 11 and also for guaiacol with Cl 9 and OH. 15 Recent works have also shown their role in the formation of Secondary Organic Aerosols through their reaction with ozone 15,16 or hydroxyl radicals 17,18 .…”

Phototransformation of 4-phenoxyphenol sensitised by 4-carboxybenzophenone: Evidence of new photochemical pathways in the bulk aqueous phase and on the surface of aerosol deliquescent particles

“…Phenols and substituted phenols are important sources of secondary organic aerosol in the atmosphere (Yee et al, 2013). They are emitted by automobile exhaust, wood burning and industrial sources (Lesh and Mead, 1985;Hawthorne et al, 1988;Hawthorne et al, 1989), but wood burning is expected to be a major source of atmospheric phenols in winter (Hawthorne et al, 1992).…”