Non-exhaust emissions in road and railway transport

Expected Outcome

Project results are expected to contribute to all of the following expected outcomes:

• Methods and tools to support measurement, simulation and validation of non-exhaust pollutant emissions in road and railway transport into the environment;
• Estimates on the impact of these pollutants on human health, terrestrial ecosystems and the aquatic environment (including biodiversity in these ecosystems) with particular focus on microplastics and other heavier non-airborne particles;
• Delivery of better emission factors for emission inventories and projections, including the European Monitoring and Evaluation Programme (EMEP), also for resuspension, for which little knowledge exists today;
• Recommendations and mitigation strategies including the determination of appropriate KPIs and assessing the effectiveness of control measures with an appropriate cost-benefit analysis to understand the economic and practical feasibility of different emission reduction strategies.

Scope

With continuous increase in electrification of the car fleet and railways, the share of non-exhaust particulate emissions into the environment becomes increasingly important. Non-exhaust emissions (NEE) of particles apply to all forms of ground transport and can be categorised as those coming from several sources, such as brake wear, tyre wear, pantograph-catenary wear, wheel-rail contact, road surface wear, as well as vehicle-induced resuspension of road/track dust deposited on the surface. There may be other sources, e.g. engine belts and clutch plates. Quantitative data on the magnitude of non-exhaust emissions are fragmented and highly uncertain, particularly when compared to data for exhaust emissions. Emissions vary widely according to brake, tyre and road surface material, and with driving style. Further research efforts are necessary to increase the understanding of these particles, their creation, ageing and dispersion in the environment.

Moreover, the health impact of NEEs is far less studied, and it remains unclear whether these predominately solid/non-soluble PM may induce the same effects as combustion PM. Additionally, these pollutants has been reported to adversely affect terrestrial systems and aquatic environment as well as the biodiversity; however, it is not clear to what extent.

Research into rail particulate emissions is an equally important area due to its implications for air quality, human health, and environmental impact. However, research data on the health impacts of specific particulate components is limited. Furthermore, comprehensive studies on the chemical composition of rail particulates are scarce. The impact of rail particulates on soil, water, and ecosystems and their biodiversity is not well understood, while more data is needed on how particulates disperse and deposit in different environments, especially in urban versus rural areas. Addressing these research gaps would provide a more comprehensive understanding of rail particulate emissions and contribute to the development of effective mitigation strategies.

In order to address the two aforementioned areas (road and rail), R&I actions are expected to address the following aspects:

• Methods and tools for the segregation of NEE particle sources: i) during particle collection (e.g., due to high background concentrations), ii) attribution of collected material to different sources. Appropriate real-world test conditions, equipment and sampling methods for the evaluation of particles (e.g., separation of total and solid particles)
• Source identification and characterization including detailed source apportionment (brake wear, tyre wear, wheel-rail interaction, resuspension, etc.) and chemical composition;
• Assessment of the influencing parameters: use cases (e.g. different vehicle types or tyre types), conditions (e.g. urban, rural, motorways, tunnels), driving behaviour, state of the road surface or rail tracks; attribution and distribution;
• Emission Measurement Techniques including but not limited to standardized measurement methods and real-time monitoring;
• Downstream assessment: analysis of the deposited material in the environment, assessment of its decomposition, aggregation, dispersion and degradation;
• Health Impact estimates building on existing toxicology studies (or developing new ones if deemed necessary) and long-term exposure effects supported by gender disaggregated data collection and intersectional analysis;
• Estimates on the environmental impact on soil, water, and ecosystems and their biodiversity as well as deposition patterns (i.e. how particulates disperse and deposit in different environments, especially in urban versus rural areas.)
• Mitigations through focusing on State-of-the-Art systems: test systems (including the vehicle e.g., vehicle-lightweight technologies) that can mitigate non-exhaust emissions to reach TRL 6 or higher, innovative tyre and brake designs and materials that balance durability, safety, and reduced abrasion, innovative road surfaces and texture (considering the interaction between tyre and road), runoff and drainage systems. For the railway sector mitigation solutions could include test systems addressing emissions from key mechanical interfaces (e.g., braking and wheel–rail contact), vehicle innovations to reduce wear-related emissions, and infrastructure measures such as optimized track materials, surface treatments, and improved drainage and containment systems. Consider life cycle assessment for the analysis of the systems
• Support standardization and regulation based on the recommendations in support of industrial competitiveness

Proposals should take into consideration the results of previous or on-going EU funded projects such as Leon-T, ULTRAHAS, nPETS and LIFE23-ENV-ES-LIFE NEEVE and any other similar projects.

Technology Readiness Level - Technology readiness level expected from completed projects

Activities are expected to achieve TRL 5-6 by the end of the project – see General Annex B. Activities may start at any TRL.