Volatile Organic Compounds from Logwood Combustion: Emissions and Transformation under Dark and Photochemical Aging Conditions in a Smog Chamber

Abstract

Residential wood combustion (RWC) emits high amounts of volatile organic compounds (VOCs) into ambient air, leading to formation of secondary organic aerosol (SOA), and various health and climate effects. In this study, the emission factors of VOCs from a logwood-fired modern masonry heater were measured using a Proton-Transfer-Reactor Time-of-Flight Mass Spectrometer. Next, the VOCs were aged in a 29 m Teflon chamber equipped with UV black lights, where dark and photochemical atmospheric conditions were simulated. The main constituents of the VOC emissions were carbonyls and aromatic compounds, which accounted for 50%-52% and 30%-46% of the detected VOC emission, respectively. Emissions were highly susceptible to different combustion conditions, which caused a 2.4-fold variation in emission factors. The overall VOC concentrations declined considerably during both dark and photochemical aging, with simultaneous increase in particulate organic aerosol mass. Especially furanoic and phenolic compounds decreased, and they are suggested to be the major precursors of RWC-originated SOA in all aging conditions. On the other hand, dark aging produced relatively high amounts of nitrogen-containing organic compounds in both gas and particulate phase, while photochemical aging increased especially the concentrations of certain gaseous carbonyls, particularly acid anhydrides.

Simulation of SOA Formation from the Photooxidation of Monoalkylbenzenes in the Presence of Aqueous Aerosols Containing Electrolytes under Various NO<sub><i>x</i></sub> Levels

“…Age-driven functionalization and fragmentation alter the volatility and reactivity of products and their molecular structures (Donahue et al, 2006;Rudich et al, 2007;Shilling et al, 2007;Hartikainen et al, 2018) which, in turn, varies the in-particle chemistry. Cappa and Wilson (2012) employed tunable parameters to kinetically demonstrate the evolution of SOA mass and the bulk oxygen-to-carbon atomic ratio (O:C ratio) during photochemical aging.…”

Laboratory studies of fresh and aged biomass burning aerosols emitted from east African biomass fuels – Part 1 – Optical properties

“…We hypothesized secondary organic aerosol formation as a potential phenomenon happening during dark aging. It was 460 observed that dark aging produced higher amounts of nitrogen containing organic compounds in the aerosol phase (Li et al, 2015;Ramasamy et al, 2019;Hartikainen et al, 2018) which could be a possible explanation for our experimental results. The fact that the production of non-absorbing secondary organic aerosol will increase the scattering cross-https://doi.org/10.5194/acp-2019-1156 Preprint.…”

Authors Response

“…We were inferring to work that was previously reported and focused on SOA formation during dark aging. (Tiitta et al, 2016;Li et al, 2015;Hartikainen et al, 2018). It seems that our statement regarding this was misunderstood and needs further clarification, which will be included in the revised draft.…”