Secondary organic aerosol formation from photooxidation of furan: effects of NOx and humidity

Abstract

<p><strong>Abstract.</strong> Atmospheric furan is a primary and secondary pollutant in the atmosphere, and its emission contributes to the formation of ultrafine particles and ground-level ozone. We investigate the effects of NOx level and humidity on the formation of secondary organic aerosol (SOA) generated from the photooxidation of furan in the presence of NaCl seed particles. The particle mass concentration and size distribution were determined with a scanning mobility particle sizer (SMPS). SOA mass concentration and yield were determined under different NOx and humidity levels. A significant difference is observed both in the SOA mass concentration and SOA yield variation with the initial experimental conditions. Six organic products were identified in the collected SOA by electrospray ionization exactive orbitrap mass spectrometry (ESI-Exactive-Orbitrap MS). The –COOH, –OH, –C=O and NO<sub>2</sub> functional groups were assigned in the FTIR spectra and used as the indicator for the mechanism inference. In addition, O<sub>3</sub> formation was also observed during the furan-NOx-NaCl photooxidation. Based on the MS analysis, the reaction mechanism was proposed to follow the RO<sub>2</sub>+NO pathway. A significant amount of carbonyl-rich products was detected in the SOA products from the photooxidation of furan. The SOA mass concentration and yield increase with increasing humidity, because higher aerosol liquid water content brings more aqueous phase reactions. The present study demonstrates the effect of NOx and humidity on SOA formation during the furan-NOx-NaCl photooxidation. Furthermore, the results illustrate the importance of studying SOA formation over a comprehensive range of environmental conditions. Only such evaluations can induce meaningful SOA mechanisms to be implemented in air quality models.</p>

Evolution of Organic Aerosol From Wood Smoke Influenced by Burning Phase and Solar Radiation

“…Figure 3b gives an example for the furanic group that the precursors (such as furan, methyl‐furan, and furfural) decreased in light but not in dark experiments (Figure ). Furanic compounds have been widely reported to be the main precursors of SOA in biomass (Hartikainen et al., 2018) and solid fuel burning emission (Ahern et al., 2019), and could have an SOA yield of up to 5% (Jiang et al., 2019). Table (in red) summarized all gaseous precursors, including some aromatics (benzene, toluene, and C8‐aromatics), carbonyl (acrolein, MVK, and 3‐methyl‐3‐butene‐2‐one), and phenolic (phenol and cresol for SM) compounds.…”

Millimeter-Wave Spectroscopy of Methylfuran Isomers: Local vs. Global Treatments of the Internal Rotation

“…Furan and its derivatives (furans) are heterocyclic organic compounds belonging to the family of oxygenated five-membered aromatic molecules. They are primary and secondary pollutants in the atmosphere emitted from multiple sources such as oil refining, coal mining and gasification, biomass and fossil fuel or waste combustions [ 1 , 2 ]. Furans and other heterocyclic compounds such as pyrroles (with N as the heteroatom in the ring) are produced by the pyrolysis of cellulose and are major components of the emission of wildfire burnings [ 3 ].…”

“…Once furans are emitted, they will undergo gas phase chemistry and, to an extent, will be photolyzed at actinic wavelengths to produce tropospheric ozone or they will react with the main atmospheric oxidants (OH, Cl atoms, ozone) leading to the formation of secondary organic aerosols (SOA) [ 5 ]. A similar process occurs during the night by the oxidation of furans with NO radicals [ 1 , 2 , 3 ]. These SOA affect the climate both directly and indirectly and large uncertainties still remain on their radiative forcing [ 6 ].…”

Kinetic Study of the Atmospheric Oxidation of a Series of Epoxy Compounds by OH Radicals

“…Isoprene derived epoxides are very important intermediates, which could explain at least in part the composition of ambient SOA both in urban areas (Lin et al, 2013) and remote regions (Jacobs et al, 2013;Stropoli et al, 2019;Paulot et al, 2009;Jacobs et al, 2013;Shrivastava et al, 2019). The toxicity of ultrafine particles such as SOA is not only related to their atmospheric concentration but also to the nature and chemical properties of both the precursors and the formed SOA components (Jiang et al, 2019). In this sense, epoxides are of great concern because the epoxy functional group can act as an electrophile in its interaction with DNA and nucleosides, producing carcinogenic and mutagenic damages (Ehrenberg and Hussain, 1981).…”