David A. Healy

Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384micromolg(-1) for Cr, 340micromol g(-1) for Ni, 358micromol g(-1) for Fe, 364micromol g(-1) for Mn and 188micromol g(-1) for Pd.

The use of polar organic compounds to estimate the contribution of domestic solid fuel combustion and biogenic sources to ambient levels of organic carbon and PM2.5 in Cork Harbour, Ireland

PM(2.5) samples collected at Cork Harbour, Ireland during summer, autumn, late autumn and winter, 2008-2009 were analyzed for polar organic compounds that are useful markers for aerosol source characterization. The determined compounds include tracers for biomass burning primary particles, fungal spores, markers for secondary organic aerosol (SOA) from isoprene, α-/β-pinene, and d-limonene. Seasonal and temporal variations and other characteristic features of the detected tracers are discussed in terms of aerosol sources and processes. The biogenic species were detected only during the summer period where the contributions of isoprene SOA and fungal spores to the PM(2.5) organic carbon (OC) were estimated to be 1.6% and 1% respectively. The biomass burning markers, and in particular levoglucosan, were present in all samples and attributed to the combustion of cellulose-containing fuels including wood, peat, bituminous and smokeless coal. The contribution of domestic solid fuel (DSF) burning to the measured OC mass concentration was estimated at 10.8, 50, 66.4 and 74.9% for summer, autumn, late autumn and winter periods, respectively, based on factors derived from a series of burning experiments on locally available fuels. Application of an alternative approach, namely principal component analysis-multiple linear regression (PCA-MLR), to the measured concentrations of the polar organic marker compounds used in conjunction with real-time air quality data provided similar trends and estimates for DSF combustion during all seasons except summer. This study clearly demonstrates that, despite the ban on the sale of bituminous coal in Cork and other large urban areas in Ireland, DSF combustion is still the major source of OC during autumn and winter periods and also makes a significant contribution to PM(2.5) levels. The developed marker approach for estimating the contribution of DSF combustion to ambient OC concentrations can, in principle, also be applied to other locations.

Using the WIBS-4 (Waveband Integrated Bioaerosol Sensor) Technique for the On-Line Detection of Pollen Grains

Primary biological aerosol particles (PBAP) such as pollen and fungal spores can induce allergenic responses and affect health in general. Conditions such as allergic rhinitis (hay fever) and asthma have been related to pollen concentrations. Likewise some pollen have been shown to induce ice nucleation and cloud condensation at higher temperatures than those associated with some chemical species, thereby affecting planet Earths albedo and overall radiative balance. Hence, the near real-time (on-line) monitoring of airborne pollen and other PBAP using a variety of spectroscopic and light scattering techniques represents an area of growing development and consequence. In this study, two separate field campaigns (one at a rural site in Ireland and the other at an urbanized location in Germany) were performed to detect and quantify pollen releases using a novel on-line fluorescence spectrometer (WIBS-4). The results were compared with results obtained using more traditional Hirst-type impactors. Size, “shape,” and fluorescence characteristics of ambient particles were used to determine the concentrations and identity of the PBAP likely to be pollen grains. The concentration results obtained for both methodologies at both the Irish and German sites correlated very well, with R 2 values >0.9 determined for both campaigns. Furthermore, the sizing data available from the WIBS-4 approach employed in Ireland indicated that pollen grains can be identified in appropriate conditions. WIBS-4 measurements of Yew pollen both in the laboratory and at the rural site indicated almost identical size ranges of 25 to 27 μm. Yew pollen is generally reported to be in this range, but the measurements reported here are the first of their type providing data on the size of in-flight Yew pollen. Copyright 2014 American Association for Aerosol Research

Atmospheric Concentrations of Alternaria, Cladosporium, Ganoderma and Didymella Spores Monitored in Cork (Ireland) and Worcester (England) During the Summer of 2010

This study represents the first international intercomparison of fungal spore observations since 1990, focusing on atmospheric concentrations of Alternaria, Cladosporium, Ganoderma and Didymella spores. The campaigns were performed at sites located in Cork (Ireland) and Worcester (England) during summer 2010. Observations were made using Hirst-type volumetric spore traps and corresponding optical identification at the genus level by microscope. The measurements at both sites (including meteorological parameters) were compared and contrasted. The relationships between the fungal spore concentrations with selected meteorological parameters were investigated using statistical methods and multivariate regression trees (MRT). The results showed high correlations between the two sites with respect to daily variations. Statistically significant higher spore concentrations for Alternaria, Cladosporium and Ganoderma were monitored at the Worcester site. This result was most likely due to the differences in precipitation and local fungal spore sources at the two sites. Alternaria and Cladosporium reached their maxima a month earlier in Cork than in Worcester, and Didymella with Ganoderma peaked simultaneously with similar diurnal trends found for all the investigated spore types. MRT analysis helped to determine threshold values of the meteorological parameters that exerted most influence on the presence of spores: they were found to vary at the two sites. Our results suggest that the aeromycological profile is quite uniform over the British Isles, but a description of bioaerosols with respect to overall load and daily concentration can be quite diverse although the geographical difference between sites is relatively small. These variations in the concentrations therefore need to be explored at the national level.

Using a pattern recognition approach to link inorganic chemical fingerprints of ambient PM 2.5-0.1 with in vitro biological effects

Atmospheric fine particulates act as prime vehicles for the transport of toxic chemicals into the human respiratory system on a daily basis and adverse human health effects do exist. By examining toxicological differences and chemical composition of ambient fine particles using a novel experimental design and chemometric approach, the present work examines the hypothesis: that it is not clear whether there are significant differences in public health risk from exposure to fine particles in a rural location compared to those in urban locations. In the present study, an investigation into the inorganic chemical characteristics and biological effects of PM2.5–0.1 on human lung epithelial cell line A549 has been performed. Biological responses were evaluated by in vitro tests using equivalent masses of PM2.5–0.1 samples, collected during different seasons at urban and rural locations in Cork, Ireland. The relationship between the biological responses and the chemical composition of the samples were investigated using Principal Component Analysis followed by Partial Least Squares regression analysis. The PM2.5–0.1 samples collected at three contrasting sites in Cork demonstrated the ability to generate reactive oxygen species upon exposure irrespective of season. However, the magnitude of generation was somewhat higher for samples collected in the urban sites, compared to those generated by rural samples. Similarly, metals such as Cu and Mn were found to be present in larger quantities in the urban-based composite samples compared to those for their rural counterparts. The induction of interleukin 6 determined in this study followed a very similar seasonal trend to the measured concentrations of potassium ions in the PM2.5–0.1 samples to which the A549 cells were exposed. The current study provides further support that identifying important chemical components and their sources, with subsequent targeted emission controls, which will likely prove to be a more cost-effective strategy for mitigating toxicity and protecting human health, than current approaches which depend on uncharacterized total particle mass, especially when sophisticated pattern recognition techniques are employed to assess limited airborne datasets.

Using spectral analysis and fluorescence lifetimes to discriminate between grass and tree pollen for aerobiological applications

A study has been performed that provides the first fluorescence lifetime results on the intrinsic fluorescence monitored for specific in situ biochemical components of individual pollen grains. The results obtained show that such measurements can provide a basis for analytical discrimination between a variety of airborne grass and tree pollen.

Airborne emissions in the harbour and port of Cork.

It is now accepted that the transport sector is responsible for a large and growing share of global emissions affecting both health and climate. The quantification of these effects requires, as an essential first step, a comprehensive analysis and characterization of the contributing subsectors, i.e. road transport, shipping, aviation and rail. The shipping contribution in dock/harbour areas is of particular interest because many vessels use old engines powered with old technology giving rise to high levels of particulate emissions mainly because the fuel employed contains high levels of sulphur, up to 4.5%. Large amounts of polyaromatic hydrocarbons and varying contents of transition metals are also detected. Few studies on the physicochemical composition of direct emissions from ship fuels have been performed; none have been compared to actual contents in local harbour or port atmospheres. The transformation of these ship-related materials to toxicologically active species may be much more efficient than corresponding road emission or domestic sources because of the expected highly acidic nature of the particulates. Surface, toxic material may therefore become readily bioavailable under such conditions but such studies have not been performed hitherto. This mini-review outlines in detail the issues raised above in the context of measurements made in Cork, Ireland.

A review of oxyhalide disinfection by-products determination in water by ion chromatography and ion chromatography-mass spectrometry

This paper is a review of ion chromatographic (IC) separations of inorganic oxyhalide disinfection by-products (DBPs) in water and beverages. The review outlines the chemical mechanisms of formation, regulation of maximum allowable levels, chromatographic column selection and speciation. In addition, this review highlights the application of IC coupled to mass spectrometry (MS) for trace and elemental composition analysis of oxyhalides, along with the analytical considerations associated to enable sensitive analysis. Furthermore, a review of literature concerning IC determination of inorganic oxyhalide DBPs in environmental matrices, including water, published since 2005 is presented, with a focus on MS detection, and a discussion on the relative performance of the methods. Finally some prospective areas for future research, including fast, selective, multi-analyte analysis, for this application are highlighted and discussed.