During the first project period (months 1-18) the necessary administrative systems and operating bodies were established, along with tools for internal and external communication and dissemination. Exposure systems and cell models were optimized, standard operating procedures (SOPs) developed to align test systems across partner labs, as well as tools for health impact assessment. In a pilot-campaign performed in collaboration with another ongoing project, fresh and aged emissions from light-duty vehicles were tested in different lung cell models, providing valuable input for the main ULTRHAS test campaigns. Studies were also performed with model UFPs (from a soot generator) varying content of semi-volatile organic chemicals (SVOCs) to further explore the importance of particle composition. At the end of the first reporting period, the first major ULTRHAS test campaign on aircraft (JP-8 feul) and ship emissions from Heavy Fuel Oil (HFO) and low-sulfur marine Gas Oil (MGO) was successfully performed, and results were analyzed into the next period.
In the second project period (months 19-36), the project performed two more large test campaigns: non-exhaust emission testing at the Bundeswehr University (UniBW) and the Helmholtz Center in Munich, and light duty/passenger car emission testing at the University of Eastern Finland, in Kuopio. In the non-exhaust emission campaign, break emissions were tested from non-asbestos organic (NAO) brake pads and low metallic (LM) brake pads, on a novel Euro 7 compatible brake dyno developed at UniBW. Furthermore, a spark discharge aerosol generator producing copper-rich UFPs was used to simulate rail catenary sparking. In the light-duty vehicle campaign fresh and aged emissions were produced from Euro 6d gasoline, diesel, and natural gas engines. The emissions from all test campaigns, comprehensively characterized for physical and chemical properties, and 3D lung tissue models have been exposed at Air-Liquid Interface (ALI). In vitro tissue/cell models of brain, blood, liver, and intestine are now exposed to conditioned medium sampled from the basolateral compartment of the ALI-exposed lung tissue model, to simulate and explore potential effects on organs beyond the lung.
In the final period (month 37-52), the analysis of emission characteristics and toxicity testing in the lung cell model and secondary tissue models have been finalized, including assessment of effects in primary cells from male and female donors, and male and female mice. Hazard ranking of different transport mode emissions has been performed, and the mechanisms of toxicity have been studied with emphasis on the physicochemical characteristics in driving biological effects (e.g. particle size-fractions, organic chemicals, metals, and gaseous components). Health impact assessment of transport mode emissions has been performed, and policy scenarios have been developed and evaluated.
The results show that emissions from transport modes differ markedly in composition and emission characteristics: while all sources emit large numbers of ultrafine particles (UFPs), high-power engines in shipping and aviation emit far higher particle mass and number concentrations per unit fuel than modern Euro 6d passenger cars, particularly under low-load operation near populated areas. Atmospheric ageing consistently increases particle mass and number through secondary aerosol formation. However, toxicological responses do not scale with particle metrics. Instead, toxicity appears primarily driven by chemical composition, especially organic compounds in gas-phase and adsorbed to particle surfaces. This indicates that current air-quality metrics based mainly on PM2.₅ mass may underestimate health risks from fresh exhaust emissions, particularly from road traffic where effects primarily seem to be due to gas phase components. Although aviation and shipping rank highest in hazard per fuel burned, population health impacts are dominated by road traffic due to vehicle numbers and proximity to people. Furthermore, fresh emissions from modern Euro 6d diesel and gasoline cars, rank highest in hazard when compared at equal PM emission levels. Overall, the findings show that regulating particle size or number alone is insufficient, and that emission chemistry is the key determinant of health effects. The main policy advice is to accelerate electrification of the passenger car fleet and other road vehicles —and electrification of ship docking and aircraft ground operations—as the most effective and immediately available strategies to protect public health while also delivering climate benefits.
