Properties of aerosol particles produced by combustion of novel fuels

Modern society still relies heavily on burning fossil fuels, a process that releases CO₂ and tiny particles that warm the planet. As the world searches for cleaner options, alternative fuels like hydrogen and methanol are gaining attention. They can drastically reduce carbon emissions, but they also change how flames behave, and that can influence the particles produced during combustion. Understanding those particles matters, because their size, composition, and ability to absorb light all affect their climate impact.

This thesis explored how switching to cleaner fuels alters the formation and properties of combustion-generated particles. Experiments with hydrogen‑blended flames showed that adding hydrogen reduces the amount of particulate matter and slows the transformation of freshly formed particles into more mature, soot‑like material. The balance between organic and elemental carbon shifted significantly, revealing how fuel composition shapes particle properties.

Further experiments examined particles sampled farther from the flame, showing that hydrogen not only reduces particle size but also changes how organic and black‑carbon components mix within each particle. Some of the organic material was found to absorb light, suggesting the presence of “brown carbon,” a species with its own climate relevance.

Finally, tests in a retrofitted diesel engine demonstrated the practical challenges of introducing methanol as a cleaner fuel. While methanol reduced harmful nitrogen oxide emissions, it also increased black‑carbon output and altered particle characteristics, underscoring the need for careful emission control strategies.

Overall, the work highlights that alternative fuels can reduce emissions but also reshape the particles produced, an important factor in designing cleaner combustion systems.