Aqueous-Phase Production of Secondary Organic Aerosols from Oxidation of Dibenzothiophene (DBT)

Abstract

Intermediate-volatility organic compounds (IVOCs) have been recognized as an important contributor to the secondary organic aerosol (SOA) formation via gas-phase reactions. However, it is unclear whether or not IVOCs-SOA can be produced in the aqueous phase. This work investigated aqueous oxidation of one model compound of IVOCs, dibenzothiophene (DBT). Results show that DBT can be degraded by both hydroxyl radical and the triplet excited states of organic light chromophores (3C*). Aqueous dark oxidation of DBT was also possible. SOA yields of 32% and 15% were found for hydroxyl radical (OH)-mediated photo-oxidation and dark oxidation, respectively. A continuous and significant increase of oxidation degree of SOA was observed during OH photo-oxidation, but not during the dark oxidation. Factor analyses revealed that there was a persistent production of highly oxygenated compounds from the less oxygenated species. OH-initiated photochemical reactions can also produce species with a relatively large light-absorbing ability, while such photo-enhancement due to direct light irradiation and 3C*-initiated oxidation could occur, but is much less important. In the future, studies on the second-order rate constants, molecular characterization of the oxidation products from this and other IVOCs precursors are needed to better understand the role of this reaction pathway in SOA budget, air quality and climate change.

A review on factors influencing fog formation, classification, forecasting, detection and impacts

“…Addition of more aerosols: Primary aerosol, which is water-soluble, when comes in contact with fog, gets trapped in the fog droplet by aqueous processing. Once in the aqueous phase, the aerosol particles undergo an oxidation reaction and become secondary aerosol (Liu et al 2020b ). The SOA (Secondary Organic Aerosol) are less volatile organic compounds that are products of VOC (Volatile Organic Compound) that either gets attached to the existing particle whose surface area is more but the supersaturation of the gas is less or they form new particles (Herckes e al.…”

Inherently Functionalized Carbon from Algae to Adsorb Precursors of Secondary Organic Aerosols in Noncombustion Sources

“…Dibenzo-thiophene, a sulfur-containing polycyclic aromatic compound consisting of a thiophene ring flanked by two benzene rings (Figure 3), belongs to the intermediate-volatile organic compounds that have been recognized as contributors to secondary organic aerosols. 55 As one of the most abundant S-containing compounds in the atmosphere, dibenzo-thiophene is emitted from burning wood, 56 incomplete combustion, 57 and noncombustion resources such as bitumen. 8 Dibenzo-thiophene is also found in crude oil and petroleum, from which it is removed before further use.…”

Size‐dependent Molecular Characteristics and Possible Sources of Organic Aerosols at a Coastal New Particle Formation Hotspot of East China

“…Half of each PM 2.5 filter was extracted with 20 ml water for bulk chemical composition analysis by using a Soot Particle‐AMS (SP‐AMS, Aerodyne Research Inc.). Offline AMS technique has been well applied to measure re‐aerosolized filter extracts of both ambient aerosols (Chen et al., 2018, Chen, Li, et al., 2020; Ge et al., 2017; Ye et al., 2017) and laboratory generated SOA (Chen, Xie, et al., 2020; Liu et al., 2020; Lu et al., 2019; Ye, Qu, et al., 2019, Ye, Zhuang, et al., 2019). These peer‐reviewed papers suggest offline AMS technique provides a low cost method for long‐term or multi‐site measurements of aerosol particles.…”