Contribution of Nitrated Phenols to Wood Burning Brown Carbon Light Absorption in Detling, United Kingdom during Winter Time

Abstract

We show for the first time quantitative online measurements of five nitrated phenol (NP) compounds in ambient air (nitrophenol C6H5NO3, methylnitrophenol C7H7NO3, nitrocatechol C6H5NO4, methylnitrocatechol C7H7NO4, and dinitrophenol C6H4N2O5) measured with a micro-orifice volatilization impactor (MOVI) high-resolution chemical ionization mass spectrometer in Detling, United Kingdom during January-February, 2012. NPs absorb radiation in the near-ultraviolet (UV) range of the electromagnetic spectrum and thus are potential components of poorly characterized light-absorbing organic matter ("brown carbon") which can affect the climate and air quality. Total NP concentrations varied between less than 1 and 98 ng m(-3), with a mean value of 20 ng m(-3). We conclude that NPs measured in Detling have a significant contribution from biomass burning with an estimated emission factor of 0.2 ng (ppb CO)(-1). Particle light absorption measurements by a seven-wavelength aethalometer in the near-UV (370 nm) and literature values of molecular absorption cross sections are used to estimate the contribution of NP to wood burning brown carbon UV light absorption. We show that these five NPs are potentially important contributors to absorption at 370 nm measured by an aethalometer and account for 4 ± 2% of UV light absorption by brown carbon. They can thus affect atmospheric radiative transfer and photochemistry and with that climate and air quality.

Estimating the contribution of organic acids to northern hemispheric continental organic aerosol

“…Acetate (CH 3 COO À ) reagent ions was used to ionize and detect acids, including peroxyacids [Veres et al, 2008;Lopez-Hilfiker et al, 2015]. Recent studies have also shown that this reagent ion can be used to measure polyphenols and nitrated phenols, benzoyl peroxide by proton abstraction with similar sensitivity as carboxylic acids [Mohr et al, 2013;Lopez-Hilfiker et al, 2015], and glyoxal, methylglyoxal, and levoglucosan, with far lower sensitivity, via clustering reactions [Veres et al, 2010;Aljawhary et al, 2013]. Since there was no biomass burning influence during BEACHON-RoMBAS, we assume that the contribution of phenols and levoglucosan to the particle-phase acid signal calculated here is minimal.…”

Observations of fine particulate nitrated phenols in four sites in northern China: concentrations, source apportionment, and secondary formation

“…Due to their strong absorption in the near-ultraviolet and visible regions, nitrated phenols are classified as poorly characterized brown carbon (BrC) (Desyaterik et al, 2013;Teich et al, 2017). Though the absorption of BrC is weak compared to that of black carbon (BC), it can enhance the absorption of solar radiation and may have an indirect effect on regional climate (Feng et al, 2013;Mohr et al, 2013;Laskin et al, 2015;Lu et al, 2015;Zhao et al, 2015). Recent studies have shown that several semivolatile nitrated phenols, including nitrophenol, nitrocatechol, and methyl-nitrocatechol (NC), are important photochemical oxidation products of gas-phase precursors, which may play a part in the formation of secondary organic…”

“…Wang et al: Observations of fine particulate nitrated phenols aerosols (SOAs; Pereira et al, 2015). Via photo-oxidation and aqueous-phase reactions, nitrated phenols could alter the tropospheric photochemistry and influence SOA formation, thus affecting regional air quality and atmospheric visibility (Mohr et al, 2013;Laskin et al, 2015;Chow et al, 2016;Yuan et al, 2016). In addition, nitrated phenols are hazardous to plants, animals, aquatic life, and humans (Natangelo et al, 1999;Schüssler and Nitschke, 2001;Harrison et al, 2005a;Ganranoo et al, 2010).…”

“…In recent decades, nitrated phenols have drawn attention because of their prevalence in biomass burning plumes (Kahnt et al, 2013;Mohr et al, 2013). Due to the good correlation with levoglucosan, Iinuma et al (2010) pointed out that NCs could be a reasonable tracer for biomass burning events.…”

Observations of nitrated phenols in four sites in North China: Concentrations, source apportionment, and secondary formation

“…Due to their strong absorption in the near-ultraviolet and visible regions, nitrated phenols are classified as poorly characterized "Brown Carbon" (BrC) (Desyaterik et al, 2013;Teich et al, 2017). Though the absorption of BrC is weak compared to that of Black Carbon (BC), it can enhance the absorption of solar radiation and may have an indirect effect on regional climate (Feng et al, 2013;Mohr et al, 2013;Laskin et al, 2015;Lu et al, 10 2015; Zhao et al, 2015). Recent study has shown that several semivolatile nitrated phenols, including nitrophenol, nitrocatechol, and methylnitrocatechol, are important photochemical oxidation products of gas phase precursors, which may play a part in the formation of secondary organic aerosols (SOA) (Pereira et al, 2015).…”