Probing the role of chemical composition on the toxicity of atmospheric particles

Over the last decade our understanding of the impact of air pollution on both short- and long-term population health has advanced considerably and there is now a better understanding of the impacts of air pollution beyond the lungs. However, there are still major gaps in our understanding of the most harmful components within the air we breathe and the mechanisms by which they induce adverse effects. In order to link the chemical composition of air pollution with adverse health outcomes, multidisciplinary research is needed to understand the underlying causal mechanisms.

Atmospheric aerosols are extremely complex, containing many thousands of compounds (Stewart et al., 2021 https://doi.org/10.5194/acp-21-2407-2021, 2021). But which ones cause toxic effects in the human body?

A recent study in Europe showed that inorganic species, crustal materials and biogenic secondary organic aerosols control the mass of particulate matter. However, oxidative potential was associated with anthropogenic secondary organic aerosols and metals from vehicle non-exhaust emissions. This suggests that policies that aim to mitigate only the mass of particles present in the atmosphere may not reduce oxidative potential or other measures of exposure.

To survive the toxicity of chemicals in the environment, cells across all species have evolved a range of distinct stress-inducible cytoprotective mechanisms. The activation of these pathways in vivo therefore provides an early biomarker of toxicity and a means of evaluating the relative hazard of different chemicals or responses secondary to the development of oxidative stress and inflammation.

This unique cross disciplinary project will link researchers in aerosol chemistry, air quality and toxicology to investigate the health effects of exposure to different chemical functionalities within atmospheric particulate matter.

This project will be co-supervised by Prof Jacqui Hamilton and Prof Ally Lewis at the Wolfson Atmospheric Chemistry Laboratories in the Chemistry Department at the University of York. In order to simplify the complexity of the atmosphere, laboratory experiments using simulation chambers can be used to create secondary organic aerosols (SOA) from individual volatile organic compounds. The student will use state of the art chromatographic and high resolutions mass spectrometric tools to understand the composition of SOA. This project will investigate the differential toxicity of SOA formed from biogenic and anthropogenic sources.

The student will also carry out exposure experiments at the School of Medicine at the University of Dundee with project partners Prof Roland Wolf and Dr Francisco Inesta-Vaquera. Here biological/enzymatic approaches will be used to modify the composition of SOA extracts, either systematically removing functional groups or via oxidative transformation. The change in composition and corresponding change in toxicity will be determined. This will allow an assessment of which types of molecules in aerosol particles pose the greatest risk to human health. This will allow policy makers to identify which aerosol sources should be reduced to minimise health risks.

The student will work within the HIPTOX project, funded by the Natural Environment Research Council and the Medical Research Council. This project aims to develop a unique Air Pollution Hazard Identification Platform and involves collaborators from Universities of Manchester, Birmingham, Edinburgh, Imperial College London, Dundee and the NIHR Manchester Clinical Research Facility.