Professor of Chemistry and founding director of the Centre for Research into Atmospheric Chemistry at University College Cork
Aerosols from residential solid fuel burning in Ireland: a science to policy perspective
The levels of fine particulate matter (PM2.5) in urban areas across Europe are elevated in winter months due to the burning of solid fuels for home heating. Identifying and quantifying the contribution that solid fuel burning makes to ambient PM2.5 is therefore a major goal in air pollution research. In this presentation, results from field-based research on residential solid fuel burning in towns and cities across Ireland over the last 15 years will be discussed. The studies employed online aerosol mass spectrometry techniques for the real-time, in situ chemical characterisation of PM2.5 and for obtaining chemical fingerprints of the aerosol particles produced from burning different solid fuels. This approach allowed source contribution estimates to be made for each fuel type – namely, peat, wood and coal. The outcomes of this research were instrumental in informing the development of the new Solid Fuel Regulations implemented by the Irish government in 2022. Preliminary results from a current project to assess the impact of these regulations on ambient air quality will also be presented.
Professor of Atmospheric Composition at The University of Manchester
Aerosols effects on marine clouds and climate: changes in shipping emissions and climate cooling
Emissions from shipping greatly influence air quality close to port cities and in the region inshore waters in highly active shipping lanes. In addition, ships emit substantial particulate matter and have a profound effect on cloud properties in the background oceanic boundary layer. On 1st January 2020, the International Maritime Organisation globally regulated the sulphur content of ship fuel to be below 0.5%. Prior to this date, the sulphur content of the fuel used by shipping in international waters was typically 3.5%. This talk will present evidence from airborne field experiments to show the influence of these changes on the marine particle population and the effect this has had on clouds. The role this has played in influencing climate will be discussed. There is a rapidly growing interest in solar radiation management. Climate scientists agree that the primary focus for reducing global warming and the associated climate change is through rapid decarbonisation to reduce our emissions of greenhouse gases. However, current global pledges for abatement of carbon dioxide emissions mean that soon the planet will exceed the 1.5C above pre-industrial levels that was agreed in the legally binding Conference of Parties (COP21). These issues have led to so-called ‘Climate Intervention’ strategies such as Marine Cloud Brightening. This will be discussed and along with the lessons that can be learned from the changes in shipping emissions.
Professor of Atmospheric Chemistry
Metal containing aerosols in the atmosphere: speciation, reactivity, and health impacts
About 0.2% of the Earth’s water is in the atmosphere. Rain, fog, clouds and deliquescent aerosols create a water phase that can shift the reactivity of volatile and non-volatile species to form new products that would not otherwise form from gas phase reactions. A notable example of processes promoted by aqueous environments is coordination chemistry. Such process leads to the formation of metal-ligand complexes between different species in the aerosols, and it can increase the solubility of particle-bound metals, therefore their bioavailability, and their capability to generate reactive oxygen species.
We investigated the formation of metal-organic ligand complexes, especially those involving small dicarboxylic acids, in urban aerosol collected in the city centre of Padua, in the Po Valley (Italy), in marine aerosol from a remote coastal environment in Henties Bay (Namibia), and in volcanic aerosol collected from the summit of Mt Etna (Italy). Aerosol samples were then characterised for quantification of metals, using inductively coupled plasma mass spectrometry (ICP-MS) and inorganic and organic ligands, using ion chromatography (IC) with conductimetric detection. The model E-AIM was used to calculate the aerosol liquid water content and the pH of the aerosols. Thermodynamic modelling, using Visual MINTEQ, was used to gain the speciation picture of the equilibria in solution in the deliquescent aerosol phase. Synchrotron-based X-ray absorption spectroscopy (XAS) was used to directly determine the oxidation state and chemical coordination sphere of iron.
For urban samples, we assessed the effects of metal-ligand complexes formation on the solubility and solubilisation kinetic of metals from the particles to both fog waters and a surrogate lung fluid. We found contrasting results in terms of solubilities and dissolution kinetics in the two aqueous environments studied. Finally, we exposed pulmonary cells to metals in different chemical forms to assess their toxicity, as well as determined their oxidative potential and their ability to promote protein aggregation linked to the development of neurodegenerative diseases.
