Primary and secondary emissions from upland fires in Ireland
University College Cork
Emissions from wildfires have detrimental effects on air quality, climate change and human health. Despite frequent occurrence of wildfires and prescribed agricultural burns in upland areas, data on wildfire emissions in Ireland is scarce. This work was conducted as part of FLARES (Fire, Land and Atmospheric Remote Sensing of EmissionS), a project funded by the Irish Environmental Protection Agency (EPA) to improve the understanding of Irish upland fire emissions. Emission factors (EF) of typical Irish wildfire fuels (heather, gorse, purple moor grass) were measured for the first time. Emission factors were measured for a set of gases (carbon monoxide CO, carbon dioxide CO2, methane CH4, sulphur dioxide SO2 and nitric oxides NOx as NO), particulates and particulate fractions (fine particulate matter PM2.5, total particulate matter TPM, black carbon BC, organic carbon OC, elemental carbon EC and total carbon TC) and molecular biomarkers (levoglucosan, mannosan, galactosan, 4-Nitrocatechol 4-NC, 4-Nitrophenol 4-NP and 4-Nitroguaiacol 4-NG). Emission factors of measured gases were as follows: CO: 42 g/kg (heather), 27 g/kg (moor grass) and 80 g/kg (gorse); CO2 1167 g/kg (heather), 1558 g/kg (moor grass) and 1442 g/kg (gorse); SO2: 1.38 g/kg (heather), 1.08 g/kg (moor grass) and 1.68 g/kg g/kg (gorse); NOx as NO: 4.46 g/kg (heather), 5.51 g/kg (moor grass), and 6.85 g/kg (moor grass); CH4: 0.21 g/kg (moor grass) and 0.38 g/kg (gorse). Particulate EFs resulted in EF of 4.71 g/kg (heather), 2.42 g/kg (moor grass) and 10.46 g/kg (gorse) for PM2.5; 3.95 g/kg (heather), 4.26 g/kg (moor grass) and 14.33 g/kg (gorse) for TPM; 0.26 g/kg (heather), 0.21 g/kg (moor grass) and 0.50 g/kg (gorse) for BC; 1.28 g/kg (heather), 1.26 g/kg (moor grass) and 5.43 g/kg (gorse) for OC; 0.80 g/kg (heather), 0.81 g/kg (moor grass) and 2.23 g/kg (gorse) for EC; 2.09 g/kg (heather), 2.07 g/kg (moor grass) and 7.65 g/kg g/kg (gorse) for TC. EFs for biomarkers were 0.09 g/kg (heather), 0.18 g/kg (moor grass) and 0.19 g/kg (gorse) for levoglucosan; 0.01 g/kg (heather), 0.01 g/kg (moor grass) and 0.01 g/kg (gorse) for mannosan and 0.01 g/kg (heather), 0.01 g/kg (moor grass) and 0.02 g/kg (gorse) for galactosan; 0.78 mg/kg (heather), 0.42 mg/kg (moor grass) and 1.36 mg/kg (gorse) for 4-NC; 0.05 mg/kg (heather), 0.04 mg/kg (moor grass) and 0.07 mg/kg (gorse) for 4-NP and 0.25 mg/kg (heather), 0.15 mg/kg (moor grass) and 0.34 mg/kg (gorse) for 4-NG. Combustion took place under flaming combustion conditions, reflected in high modified combustion efficiencies (MCE) of 0.95 to 0.98. Emissions for species like CO, PM2.5 and volatile organic compounds (VOCs) would be expected to be higher under real-world conditions where MCE is lower. Secondary organic aerosol (SOA) formation from combustion emissions of the three fuels was studied under simulated day-time (UV lights and UV+OH precursor addition) and night-time conditions (dark + O3 addition) in an atmospheric simulation chamber. SOA mass increased by 2-11% and was dependent on fuel type and oxidising conditions. Field and laboratory samples were analysed at the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany. Filter samples were analysed for the biomarkers levoglucosan, mannosan, galactosan, 4-nitrocatechol, 4-nitrophenol, and 4-nitroguiacol. Laboratory experiments were complemented by field studies. Ambient levels of PM2.5 and BC were measured during an 8-week field study in Glencree, rural Co. Wicklow, Ireland. Source appointment of BC and analysis of biomarkers found no unambiguous signals that could be associated with wildfires. However, this dataset represents a valuable glance at air quality in a rural setting in Ireland. Despite the remote location and low population density in Glencree Valley, anthropogenic influences on air quality were significant, most notably from residential solid fuel burning. Monthly PM2.5 concentrations in Glencree (4.6 μg m–3) were lower than in nearby urban Tallaght (7.0 μg m–3), but less than expected based on the difference in population and local pollution sources. Other field observations included opportunistic sampling of the plume of a major wildfire at Killarney National Park, Co. Kerry, in April 2022. Findings presented in this thesis contribute to the understanding of wildfire emissions in Ireland and highlight the influence of anthropogenic air pollution from solid fuel burning on rural locations.
Emission factors , Wildfires , Gorse , Air quality , Air quality rural ireland , Solid fuel burning , Gorsefire , Atmospheric aging , Atmospheric chamber , Biomarkers , Particulate matter , Levoglucosan, mannosan, galactosan, 4-nitrocatechol, 4-nitrophenol, and 4-nitroguiacol , TROPOS Leipzig , Upland fires , Air pollution , Mannosan , Galactosan , 4-Nitrocatechol , 4-Nitrophenol , 4-Nitroguiacol
Felberbauer, C. 2023. Primary and secondary emissions from upland fires in Ireland. MRes Thesis, University College Cork.