Impact of photochemical ageing on Polycyclic Aromatic Hydrocarbons (PAH) and oxygenated PAH (Oxy-PAH/OH-PAH) in logwood stove emissions

Toni Miersch; Hendryk Czech; Anni Hartikainen; Mika Ihalainen; Jürgen Orasche; Gülcin Abbaszade; Jarkko Tissari; Thorsten Streibel; Jorma Jokiniemi; Olli Sippula; Ralf Zimmermann

doi:10.1016/j.scitotenv.2019.05.412

Impact of photochemical ageing on Polycyclic Aromatic Hydrocarbons (PAH) and oxygenated PAH (Oxy-PAH/OH-PAH) in logwood stove emissions

Sci Total Environ. 2019 Oct 10:686:382-392. doi: 10.1016/j.scitotenv.2019.05.412. Epub 2019 May 31.

Authors

Affiliations

¹ Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany.
² Fine Particle and Aerosol Technology Laboratory, Department of Environmental and Biological Science, University of Eastern Finland, Yliopistonranta 1, P.O. Box 1672, 70211 Kuopio, Finland. Electronic address: hendryk.czech@uni-rostock.de.
³ Fine Particle and Aerosol Technology Laboratory, Department of Environmental and Biological Science, University of Eastern Finland, Yliopistonranta 1, P.O. Box 1672, 70211 Kuopio, Finland.
⁴ Joint Mass Spectrometry Centre, Cooperation Group "Comprehensive Molecular Analytics" (CMA), Helmholtz Zentrum München, Gmunder Straße 37, 81479 München, Germany.
⁵ Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Cooperation Group "Comprehensive Molecular Analytics" (CMA), Helmholtz Zentrum München, Gmunder Straße 37, 81479 München, Germany.
⁶ Fine Particle and Aerosol Technology Laboratory, Department of Environmental and Biological Science, University of Eastern Finland, Yliopistonranta 1, P.O. Box 1672, 70211 Kuopio, Finland; Department of Chemistry, University of Eastern Finland, Yliopistokatu 1, P.O. Box 111, 80101 Joensuu, Finland.

PMID: 31181524
DOI: 10.1016/j.scitotenv.2019.05.412

Abstract

The combustion of spruce logwood in a modern residential stove was found to emit polycyclic aromatic hydrocarbons (PAH) and oxygenated polycyclic aromatic hydrocarbons (OPAH) with emission factors of 404 μg MJ^-1 of 35 analysed PAH, 317 μg MJ^-1 of 11 analysed Oxy-PAH and 12.5 μg MJ^-1 of 5 analysed OH-PAH, most of which are known as potential mutagens and carcinogens. Photochemical ageing in an oxidation flow reactor (OFR) degraded particle-bound PAH, which was also reflected in declining PAH toxicity equivalent (PAH-TEQ) values by 45 to 80% per equivalent day of photochemical ageing in the atmosphere. OPAH concentrations decreased less than PAH concentrations during photochemical ageing, supposedly due to their secondary formation, while 1-hydroxynaphthalene, 1,5-dihydroxynaphthalene and 1,8-naphthalaldehydic acid were significantly increased after ageing. Furthermore, secondary organic aerosol (SOA) formation and aromatic compounds not included in targeted analysis were investigated by thermal-optical carbon analysis (TOCA) hyphenate to resonance-enhanced multi-photon ionisation time-of-flight mass spectrometry (REMPI-TOFMS). The commonly used PAH-source indicators phenanthrene/anthracene, fluoranthene/pyrene, retene/chrysene, and indeno[cd]pyrene/benzo[ghi]perylene remained stable during photochemical ageing, enabling identification of wood combustion emissions in ambient air. On the other hand, benz[a]pyrene/benz[e]pyrene and benz[a]anthracene/chrysene were found to decrease with increasing photochemical age. Retene/chrysene was not a proper classifier for the wood combustion emissions of this study, possibly due to more efficient combustion than in open wood burning, from which this diagnostic ratio was initially derived. This study motivates in-depth investigation of degradation kinetics of particle-bound species on different combustion aerosol as well as the consequences of photochemical ageing on toxicity and identification of wood combustion emissions in ambient air.

Keywords: Diesel exhaust particles; EC/OC; PEAR; Photoionization mass spectrometry; Toxicity equivalent; Wood combustion.