Communication activities

Mid-project newsletter

Progress towards achieving IRTEMS goals

Summary of the context and overall objectives of the project:

According to the World Health Organization (WHO), outdoor air pollution causes 4.2 million premature deaths annually, most of them in urban areas where both, emission sources and population concentrate. Therefore, tackling urban air quality constitutes a pressing priority from the social and political point of view. Road transport is often the main source of air pollution in urban areas worldwide. There are several methods and approaches that are useful for different scales of analysis. Usually, regional traffic emission models based on average speed or on traffic situations are commonly used at the city scale for the compilation of urban inventories. Still, this level of detail is not enough to understand the high pollutant concentrations that occur in specific urban environments generally associated to high traffic intensity and usually referred to as hot-spots. An integrated approach that provides city-wide traffic emission estimations with high resolution in time and space for hot-spots poses a major scientific challenge.

In recent years, there has been rising concern for the environment, and along with it, a rush, in a multitude of sectors, to research and develop new ways to prevent ecological collapse and improve sustainability. One sector of high importance is that concerned with road traffic in cities, where emissions produce severe effects on citizens’ health and the environment. New emerging technologies in transport are arriving and a change in urban mobility paradigm has begun and over recent years, significant progress has been made in reducing emissions of key air pollutants from the transport sector. But, this sector is still one of the main contributors to air pollution in cities in Europe and some traffic-related air quality issues remain in urban areas worldwide. Non-compliance with European air quality standards is often linked to traffic-related highly polluted microenvironments (hot-spots) that require local intervention in addition to city-scale plans and measures. This poses a unique opportunity to develop innovative tools needed to tackle urban air pollution.

To accurately understand the high concentrations of pollutants that occur in certain urban areas and their influence on the actual exposure of the population, it is necessary to estimate the contribution of road traffic to atmospheric emissions in great detail. Models are often used for this purpose can help us to understand traffic emissions processes and how to improve air quality in our cities. With this in mind, the EU-funded project IRTEMS is developing a high-resolution road-traffic-emission-modelling system that can be applied at city scale.

IRTEMS (Instantaneous Road Traffic Emissions Modelling System for cities) is a scientific programme funded by the European Commission (H2020-MSCA-IF-2019 GA896417). The project is being coordinated by Universidad Politécnica de Madrid (UPM) located in Madrid (Spain) with North Carolina State University (NCSU) located in Raleigh (USA) as a partner organization. The project duration is of 3-years from Feb 15, 2021 to Feb 14, 2024.

This research project aims to contribute to drastically improve our knowledge to estimate the contribution of road traffic to atmospheric emissions at the city level and in great detail. The expected output from this research effort is a significant contribution to atmospheric science with a decided focus on providing useful information and tools to air quality managers and decision-makers, so that the project is also relevant policy-wise, providing knowledge-based answers for measures to be implemented for good air quality in cities.

Main goal is to develop an instantaneous road traffic emission modelling system for its application at city scale by coupling a hybrid traffic model with a microscale emission model to provide highly detailed data for air quality simulations. This is done by means of:

  • Quantify individual vehicle trip emissions at high resolution by means of a road traffic emission modelling system.
  • Validate modelled vs. measured individual trip emissions.
  • Quantify spatial and temporal variation of emissions at the city level.
  • Integrate city scale road traffic emissions into microscale air quality models.
IRTEMS project flowchart

The final result is a useful and thorough tool to provide accurate city-wide emission results considering European traffic conditions. This tool will help to give knowledge-based answers for measures to be implement for a good air quality in the European Union cities taking into account gender dimension and ethical aspects in all steps of the project. For the purpose of the project a 2-year stay in the USA with experts on measuring and modelling emissions has been successfully completed and now a 1-year returning phase to an emission and air quality modelling reference group in Europe, located in Madrid, has started. Collaborations with enterprises of the transport sector and other research organizations with expertise on instantaneous traffic emission models are contemplated through the research program. This aspect reinforces the strong inter/multidisciplinary of the project to develop a powerful tool and to provide solutions involving different aspects to generate an important impact on society. On the other hand, this project is a career opportunity that will help to generate new research lines. All the research results and knowledge generated during the project is being openly accessible through scientific publications and several dissemination activities for different target audiences. This is helping to involve different sectors on the research activities from the EU, increasing the interest of a wider part of the society. In this case, by contributing to a better air quality in accordance with the targets of the European climate action plan through the analysis of air traffic emissions.

Work performed and main results achieved so far:

The project is contributing to the knowledge on how to reduce road and air traffic emissions providing scientific outcomes to provide accurate answers on traffic emission generation and possible reduction mechanisms.

During the first two years of the project different model approaches were analysed and main outcomes of that were that models can produce similar high resolution emissions outcomes when the key parameters such as engine power and load for each vehicle class in addition to detailed driving patterns in the emission estimation are correctly considered. This analysis demonstrates the importance of an accurate definition of the model parameters for a specific vehicle fleet so that the modules selected during the project need to consider the specific vehicle fleet of the area where it is applied. These results were published on Quaassdorff, et al., 2022 (1) (

Related to how accurate model estimations can be, the precision of a microscale model was evaluated in comparison to measurements. The main outcomes were that for a selected set of 10 vehicles the model was highly accurate, at 86% to 97% across pollutants, in locating measured hotspots and non-hotspots (2). The precision of the model in identifying hotspots depends on the pollutant and lower precision estimation can be related to the sample size.

Those have been main steps to contribute to the development of a high resolution modelling system that can be applied at city scale and in next steps of the project those results will contribute to its materialisation.

  1. Quaassdorff, C., Smit, R., Borge, R., Hausberger, S. (2022). Comparison of microscale traffic emission models for urban networks. Environmental Research Letters. Volume 17:094030.
  2. Quaassdorff, C., Khan, T., Frey, H. C. Accuracy of the predictions of modeled emission hotspots based on real-world measured vehicle activity and emissions. CRC Real-World Emission Workshop. San Diego, California, USA. March 13-16, 2022.

Progress beyond the state of the art, expected results until the end of the project and potential impacts:

There are several methods and approaches that are useful for different scales of analysis. To understand the spatial and temporal distribution of the emissions, typically, regional traffic emission models are used for the compilation of urban inventories and usually those are the most detailed data available at city scale. This level of detail is not enough to understand the high pollutant concentrations that occur on specific urban highly polluted microenvironments (hotspots). To accurately understand the influence of these very local high concentrations on the real exposure of the population, there is a need to estimate the contribution of road traffic to atmospheric emissions at city level but in great detail. For that, an integrated multi-scale approach is needed which is a crucial step to analyse potential air pollution abatement measures in cities. This ongoing project plans to generate a useful modelling system to analyse road traffic emissions at city scale with great detail to help to provide knowledge-based answers for measures to be implemented for good air quality in cities.

The main goal of the project is to develop a useful and thorough modelling system to provide accurate city-wide emission results for European traffic conditions that will be developed by means of the implementation of an instantaneous traffic emission modelling system with high resolution at city scale. It is expected that the modelling system is materialised as an ad-one module of commercial software or integrated in them as parameterizations which intends to be exploited.

This will help to take knowledge based answers for measures to be implemented for good air quality.