Characterization of primary and secondary wood combustion products generated under different burner loads

Abstract

Abstract. Residential wood burning contributes to the total atmospheric aerosol burden; however, large uncertainties remain in the magnitude and characteristics of wood burning products. Primary emissions are influenced by a variety of parameters, including appliance type, burner wood load and wood type. In addition to directly emitted particles, previous laboratory studies have shown that oxidation of gas-phase emissions produces compounds with sufficiently low volatility to readily partition to the particles, forming considerable quantities of secondary organic aerosol (SOA). However, relatively little is known about wood burning SOA, and the effects of burn parameters on SOA formation and composition are yet to be determined. There is clearly a need for further study of primary and secondary wood combustion aerosols to advance our knowledge of atmospheric aerosols and their impacts on health, air quality and climate. For the first time, smog chamber experiments were conducted to investigate the effects of wood loading on both primary and secondary wood combustion products. Products were characterized using a range of particle- and gas-phase instrumentation, including an aerosol mass spectrometer (AMS). A novel approach for polycyclic aromatic hydrocarbon (PAH) quantification from AMS data was developed and results were compared to those from GC-MS analysis of filter samples. Similar total particle mass emission factors were observed under high and average wood loadings; however, high fuel loadings were found to generate significantly higher contributions of PAHs to the total organic aerosol (OA) mass compared to average loadings. PAHs contributed 15 ± 4% (mean ±2 sample standard deviations) to the total OA mass in high-load experiments, compared to 4 ± 1% in average-load experiments. With aging, total OA concentrations increased by a factor of 3 ± 1 for high load experiments compared to 1.6 ± 0.4 for average-load experiments. In the AMS, an increase in PAH and aromatic signature ions at lower m / z values, likely fragments from larger functionalized PAHs, was observed with aging. Filter samples also showed an increase in functionalized PAHs in the particles with aging, particularly oxidized naphthalene species. As PAHs and their oxidation products are known to have deleterious effects on health, this is a noteworthy finding to aid in the mitigation of negative wood burning impacts by improving burner operation protocols.

Advanced source apportionment of carbonaceous aerosols by coupling offline AMS and radiocarbon size-segregated measurements over a nearly 2-year period

“…WOOA mass spectrum exhibited elevated contributions of A. Vlachou et al: Advanced source apportionment of carbonaceous aerosols , 73, 85 and 99, respectively) to the one coming from oxygenated products from a wood-burning experiment (Bruns et al, 2015) was found. The recovery of this factor manifested high values (Table 2) and consisted mainly of fine-mode particles (Fig.…”

Evolution of the chemical fingerprint of biomass burning organic aerosol during aging

“…Primary and aged emissions were characterized using a suite of instrumentation. This included a TAG-AMS (Aerodyne Research Inc.) for the online speciation of the OA particle mass, an Aethalometer (Magee Scientific Aethalometer model AE33) (Drinovec et al, 2015) for the quantification of the equivalent black carbon (BC) concentration, a HR-ToF-AMS (Aerodyne Research Inc.) for the bulk-condensed chemical composition of the non-refractory fraction of the aerosol, and a Proton Transfer Reaction -Time of Flight -Mass 15…”

“…Its ubiquity and abundance (Waked et al, 2014;Bonvalot et al, 2016;Maenhaut et al, 2016) have been used to demonstrate the significant contribution of biomass burning to the total organic aerosol source globally (Robinson et al, 2006;Gelencsér et al, 2007;Puxbaum et al, 2007;Stone et al, 2010;Crippa et al, 2013). 20 The concentration of organic aerosol (OA) particle mass has been documented to increase up to 7 times during photochemical aging (Grieshop et al, 2009;Heringa et al, 2011;Ortega et al, 2013;Bruns et al, 2015;Tiitta et al, 2016), however, the chemical composition of this secondary organic aerosol (SOA) produced remains uncertain. Multiple studies investigated the oxidation of specific gas-phase precursors commonly emitted by biomass burning, namely methoxyphenols (Net et al, 2011;Lauraguais et al, 2012;Yee et al, 2013;Lauraguais et al, 2014), but few have specifically addressed the 25 aging of specific biomass burning tracers in the particle phase (Hennigan et al, 2010;Kessler et al, 2010;Lai et al, 2014), and so far, only Fortenberry et al (2017) have attempted characterizing the aged chemical fingerprint of biomass burning emissions at the molecular level by means of a Thermal Desorption Aerosol Gas Chromatograph (TAG) connected to a Potential Aerosol Mass (PAM) flow reactor.…”

Insights into organic-aerosol sources via a novel laser-desorption/ionization mass spectrometry technique applied to one year of PM<sub>10</sub> samples from nine sites in central Europe

“…These samples did not only include the primary aerosol, but also two different levels of ageing, i.e. after simulated ageing in a smog chamber for 1 h (equivalent to an OH dose of 10 7 cm −3 h) and 4 h (OH dose 3×10 7 cm −3 h) (Bruns et al, 2015(Bruns et al, , 2016. Additionally, filter samples collected during cooking experiments were analysed (Klein et al, 2016a, b).…”