Browsing by Author "Farren, Naomi J."

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    Chemical characterisation of water-soluble ions in atmospheric particulate matter on the East Coast of Peninsular Malaysia
    (European Geosciences Union (EGU) / Copernicus Publications, 2019-02-06) Farren, Naomi J.; Dunmore, Rachel E.; Mead, Mohammed Iqbal; Mohd Nadzir, Mohd Shahrul; Abu Samah, Azizan; Phang, Siew-Moi; Bandy, Brian J.; Sturges, William T.; Hamilton, Jacqueline F.
    Air quality on the east coast of Peninsular Malaysia is influenced by local anthropogenic and biogenic emissions as well as marine air masses from the South China Sea and aged emissions transported from highly polluted East Asian regions during the winter monsoon season. An atmospheric observation tower has been constructed on this coastline at the Bachok Marine Research Station. Daily PM2.5 samples were collected from the top of the observation tower over a 3-week period, and ion chromatography was used to make time-resolved measurements of major atmospheric ions present in aerosol. SO 2− 4 was found to be the most dominant ion present and on average made up 66 % of the total ion content. Predictions of aerosol pH were made using the ISORROPIA II thermodynamic model, and it was estimated that the aerosol was highly acidic, with pH values ranging from −0.97 to 1.12. A clear difference in aerosol composition was found between continental air masses originating from industrialised regions of East Asia and marine air masses predominantly influenced by the South China Sea. For example, elevated SO 2− 4 concentrations and increased Cl− depletion were observed when continental air masses that had passed over highly industrialised regions of East Asia arrived at the measurement site. Correlation analyses of the ionic species and assessment of ratios between different ions provided an insight into common sources and formation pathways of key atmospheric ions, such as SO 2− 4 , NH + 4 and C 2 O 2− 4 . To our knowledge, time-resolved measurements of water-soluble ions in PM2.5 are virtually non-existent in rural locations on the east coast of Peninsular Malaysia. Overall this dataset contributes towards a better understanding of atmospheric composition in the Maritime Continent, a region of the tropics that is vulnerable to the effects of poor air quality, largely as a result of rapid industrialisation in East Asia.
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    Emissions of intermediate-volatility and semi-volatile organic compounds from domestic fuels used in Delhi, India
    (European Geosciences Union /Copernicus Publications, 2021-02-18) Stewart, Gareth J.; Nelson, Beth S.; Acton, W. Joe F.; Vaughan, Adam R.; Farren, Naomi J.; Hopkins, James R.; Ward, Martyn W.; Swift, Stefan J.; Arya, Rahul; Mondal, Arnab; Jangirh, Ritu; Ahlawat, Sakshi; Yadav, Lokesh; Sharma, Sudhir K.; Yunus, Siti S. M.; Hewitt, C. Nicholas; Nemitz, Eiko; Mullinger, Neil; Gadi, Ranu; Sahu, Lokesh K.; Tripathi, Nidhi; Rickard, Andrew R.; Lee, James D.; Mandal, Tuhin K.; Hamilton, Jacqueline F.
    Biomass burning emits significant quantities of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) in a complex mixture, probably containing many thousands of chemical species. These components are significantly more toxic and have poorly understood chemistry compared to volatile organic compounds routinely quantified in ambient air; however, analysis of I/SVOCs presents a difficult analytical challenge. The gases and particles emitted during the test combustion of a range of domestic solid fuels collected from across Delhi were sampled and analysed. Organic aerosol was collected onto Teflon (PTFE) filters, and residual low-volatility gases were adsorbed to the surface of solid-phase extraction (SPE) discs. A new method relying on accelerated solvent extraction (ASE) coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–ToF-MS) was developed. This highly sensitive and powerful analytical technique enabled over 3000 peaks from I/SVOC species with unique mass spectra to be detected. A total of 15 %–100 % of gas-phase emissions and 7 %–100 % of particle-phase emissions were characterised. The method was analysed for suitability to make quantitative measurements of I/SVOCs using SPE discs. Analysis of SPE discs indicated phenolic and furanic compounds were important for gas-phase I/SVOC emissions and levoglucosan to the aerosol phase. Gas- and particle-phase emission factors for 21 polycyclic aromatic hydrocarbons (PAHs) were derived, including 16 compounds listed by the US EPA as priority pollutants. Gas-phase emissions were dominated by smaller PAHs. The new emission factors were measured (mg kg−1) for PAHs from combustion of cow dung cake (615), municipal solid waste (1022), crop residue (747), sawdust (1236), fuelwood (247), charcoal (151) and liquefied petroleum gas (56). The results of this study indicate that cow dung cake and municipal solid waste burning are likely to be significant PAH sources, and further study is required to quantify their impact alongside emissions from fuelwood burning.