Understanding the atmospheric chemistry of domestic wood burning emissions

Large scale biomass burning events, including wildfires, agricultural burn-off and residential fuel combustion release large quantities of organic carbon to the atmosphere.  Fires can emit an extensive range of pollutants into the gas and particle phases, including many organic compounds from the degradation of cellulose and lignin. These emissions can then undergo chemical transformations leading to a wide range of harmful secondary gas and particulate products which can have a significant impact upon air quality and human health, as well as the climate.

Figure 1: Schematic of biomass burning emissions of some important oxygenated aromatics, whose atmospheric chemistry will lead to the formation of a wide range of gas and aerosol phase secondary products that can have a significant detrimental impact on climate, air quality and health

The World Health Organisation has estimated that globally 8.8 million people die each year as a direct result of exposure to air pollution (https://www.who.int/data/gho).  Exposure to poor air quality has a range of short and long term impacts on health including cardiovascular and respiratory diseases, cancer, diabetes and links to dementia (https://www.gov.uk/government/publications/clean-air-strategy-2019).

Domestic solid fuel burning, in particular wood, is now the dominant source of fine particulate matter (PM2.5) in the UK. PM2.5 is one of the biggest areas of concern for air quality and human health and caused an estimated 33,000 excess deaths in the UK in 2019 ((https://www.eea.europa.eu//publications/air-quality-in-europe-2021). Efforts have been made to reduce particulate pollution but in recent decades, solid fuel burning for space heating has only increased in popularity, with an estimated 50,000 extra homes installing new stoves each year.

Many of the organic species emitted are known to be toxic, but little is known about the impact of atmospheric ageing on the composition and toxicity of wood burning emissions.

This studentship aims to understanding the complex chemical composition and atmospheric chemistry of wood burning emissions in the UK, using samples and data collected from experiments carried out at the University of Manchester Stove Facility (https://www.manchester.ac.uk/about/news/scientists-measure-air-pollution-from-domestic-wood-burners-in-new-study/) and the European Photoreactor (EUPHORE) in Valencia, Spain (https://www.eurochamp.org/simulation-chambers/EUPHORE). There will also be scope for designing and carrying out further experiments in the outdoor chamber facility in Valencia. As part of this project we also aim to understand how emissions from wood burning change when stoves are used incorrectly or when unconventional fuels are used.

Figure 2: University of Manchester Stove Facility (left), illustrating different types of burn experiments (pre-ignition, flaming, smouldering)

The student will use state of the art analytical tools to determine the composition of the secondary organic aerosol (SOA) formed from the burning of different types of wood, under different ideal and non-ideal burn conditions (see Figure 2), in particular non-target analyses using UPLC (ultra-high pressure liquid chromatography) coupled to Orbitrap mass spectrometry (https://pubs.acs.org/doi/10.1021/acs.analchem.4c00819).

Figure 3: EUroPean HOtoREactor (EUPHORE) highly instrumented, large outdoor chamber facility, Valencia, Spain

They will use extensive datasets from the EUPHORE experiments (building on the results to design and carry out further experiments) to develop and evaluate new detailed chemical mechanisms of important gas-phase organic wood burning emissions, identified from residential solid fuel combustion and wildfire sources, for inclusion into the Master Chemical Mechanism (https://mcm.york.ac.uk). The MCM is central to a number of air quality modelling activities. It is recognized as the global gold standard benchmark description of atmospheric chemistry and is extensively used for a variety of science and policy applications, where chemical detail is required to assess issues related to atmospheric composition. The outcomes of this project will allow us to better understand the broader impacts of wood burning, in particular the UK, and provide evidence to develop better mitigation policies.

The student will work under the supervision of Dr Andrew Rickard and Professor Jacqui Hamilton and will be based at the Department of Chemistry’s Wolfson Atmospheric Chemistry Laboratories at the University of York (https://www.york.ac.uk/chemistry/research/wacl/). WACL is home to more than 75 researchers with interests in all aspects of atmospheric chemistry, from stratospheric ozone, through to urban pollution, personal exposure and health. WACL supports an exceptional environment for research, offering access to state-of-the-art facilities and includes a range of different disciplines and researchers.

The student will receive project specific training on all aspects of the instrumentation and data analysis techniques as well as comprehensive training programmes for PhD students with a range of both hard and soft skills. The student will also be affiliated to the National Centre for Atmospheric Science (https://ncas.ac.uk/) and have access to high quality scientific training and facilities. There will be opportunities for networking and sharing your work both within and beyond the University. Funding is provided to enable you to attend conferences and external training. The department also runs a varied and comprehensive seminar programme.

Prospective candidates should hold or expect to achieve the equivalent of a UK upper second class degree in subjects such as chemistry, physics, engineering, environmental science or a related field. We are looking for an enthusiastic team player with good problem-solving skills and a strong interest in atmospheric or analytical science.