The primary purpose of the EU LowC project is to determine whether new low- and zero-carbon fuels (LCF/ZCF) used in heavy-duty vehicles, aircraft, and ships can indeed help protect the environment, improve air quality, and protect people's health. Many people believe these fuels are good replacements to traditional fossil fuels, but burning them can result in complex and poorly understood emission profiles, particularly for ultrafine particles and exhaust components that react with chemicals. A thorough study is important to ensure that cuts in CO₂ emissions do not accidentally generate increases in other climatic factors or air pollutants that impact health. Modern transportation engines consume fuel and emit primary particulate matter and gases, which can rapidly alter after discharge due to air dilution and chemical ageing. Ultrafine particles (UFPs) are particularly concerning since they are extremely minute, can easily enter the lungs, and may contain hazardous compounds. Exhaust gases, like primary emissions, can produce secondary organic and inorganic aerosols (SOA/SIA). This can significantly increase PM₂.₅ mass and alter the physical and chemical characteristics of particles. However, present emission measurements often fail to account for these processes, particularly when considering actual operational settings and atmospheric ageing scenarios.

My study in the LowC project focusses on comparing the detailed characterisation of primary and secondary aerosol emissions from a wide range of low- and zero-carbon powertrains to those that run on fossil fuels. This includes testing and validating typical operational circumstances for heavy-duty on- and off-road engines, aviation powertrains, and maritime engines equipped with appropriate exhaust aftertreatment systems. At the same time, engine performance and fuel consumption are measured to ensure that fuel concepts may be compared in an objective and relevant manner. A critical aspect of my job is to investigate how transport emissions evolve in the atmosphere in a controlled laboratory setting. I investigate how secondary aerosols originate in both photochemical ageing circumstances, which mimic sunny daytime atmospheres, and dark ageing conditions, which simulate nighttime chemistry without photochemical processes. These assays assess SOA and SIA formation, PM₂.₅ levels, and identify precursor chemicals and potentially dangerous aerosol components that form over time.

A variety of cutting-edge online and offline aerosol measurement techniques are employed to examine the physical and health-related aspects of both fresh and aged aerosols. Condensation Particle Counters (CPCs) can detect particles as small as 3 nm. A Wide Range Aerosol Spectrometer measures particle size distributions from ultrafine to 10 µm, using a Scanning Mobility Particle Sizer (SMPS) for nanoscale particles and a laser scattering spectrometer for coarse particles. We use a Fast Mobility Particle Sizer (FMPS) for particles ranging from 6 to 560 nm and an Electrical Low-Pressure Impactor (ELPI) for particles ranging from 7 nm to 10 µm to measure size more precisely. Scanning and Transmission Electron Microscopy (SEM/TEM) examines particle morphology and form in addition to size and quantity. This provides information regarding particle structure and grouping. Furthermore, particle effective density is measured using an innovative combination of an Aerosol Particle Mass Analyser (APM, Kanomax) and SMPS, allowing for a more complete understanding of particle composition, mixing state, and potential health consequences.

Using modern aerosol equipment, real-time analysis, and controlled ageing experiments, this study contributes to closing significant gaps in our understanding of how low-carbon transportation fuels affect the environment and health. The findings call for the development of cleaner propulsion technologies, improved exhaust aftertreatment systems, and evidence-based regulations to ensure that future fuel transitions result in significant reductions in climate drivers without compromising air quality.

University of Rostock
Institute of Chemistry
Division of Analytical and Technical Chemistry
Dheeraj Das
Albert-Einstein-Straße 27
18059 Rostock (Germany)

Tel.: +49 (0) 381 498 - 6533

dheeraj.dasuni-rostockde