A team from the ITACA Institute at the Universitat Politècnica de València (UPV), in collaboration with the Institute for Corpuscular Physics (IFIC), a joint center of the Spanish National Research Council (CSIC) and the University of Valencia (UV), has developed a methodology that makes it possible to calculate the pollutant gas emissions generated by traffic on each street of the city of Valencia, hour by hour. The system combines information collected by the traffic sensors already installed throughout the city with standardized and internationally recognised emission models.

Thanks to this work, it has been possible to identify the areas most affected by traffic-related pollution. The most polluted areas are the northern (Av. de Catalunya, Av. Hermanos Machado) and western (Av. del Cid, Tres Forques entrance) access points of the city. Other streets with a high traffic density, such as Pérez Galdós and Giorgeta avenues, also stand out for their high emission levels.

According to the study, in 2021 road traffic generated more than 600,000 tonnes of greenhouse gases in Valencia, as well as pollutants such as nitrogen oxides, carbon monoxide, volatile organic compounds and particulate matter.

The impact of bike lanes

The method developed by the team at the ITACA Institute of the UPV and IFIC (CSIC-UV) allows the impact of new sustainable urban mobility measures to be assessed. As an example, the ITACA team analysed the effect of converting a traffic lane into a bike lane on Avenida Reino de València. After the intervention, emissions in that section were reduced by more than 45% during peak traffic hours.

“The model makes it possible to directly estimate the impact of specific measures, with a level of detail that was previously unattainable. This allows us to simulate which measures would have the greatest effect on reducing emissions, and thus invest available resources as efficiently as possible,” says Edgar Lorenzo Sáez, researcher at the ITACA institute.

Reduction of emissions between 2016 and 2021

Furthermore, the study carried out by the UPV and IFIC team shows a progressive reduction of emissions in Valencia between 2016 and 2021. In this period, pollutants such as carbon monoxide and volatile organic compounds decreased by more than 30%. According to the study, this decline is linked to the reduced presence of diesel vehicles and the still limited but growing increase in hybrid and electric vehicles.

A more precise system

Until now, air quality control in Valencia relied on data from nine fixed stations distributed around the city. “These stations do not provide a complete picture of the city. Our system enables full coverage of the entire urban area, including streets and neighbourhoods without direct monitoring stations,” explains Jose Vicente Oliver, professor at the UPV and researcher at the ITACA institute.

“This capacity for detailed analysis is especially useful for designing low-emission zones, prioritising interventions in sensitive areas (such as schools or healthcare centres), and checking whether certain measures displace pollution to other areas or time slots. This ensures that a measure does not simply shift emissions from one part of the city to another, causing environmental injustice,” adds Javier Urchueguía, professor at the UPV and researcher at the ITACA institute.

IFIC collaborated in processing the data collected by the more than 3,500 electromagnetic loops distributed throughout the city to measure the passage of cars, bicycles and scooters. “Modern data analysis techniques have been essential for refining, validating and structuring the enormous volume of information generated by the traffic management system,” says Miguel García Folgado, CSIC researcher at the Institute for Corpuscular Physics. “Thanks to this, it has been possible to study the impact of traffic on urban pollution with unprecedented spatial and temporal resolution, precisely identifying critical emission hotspots.”

To carry out this study, the UPV and IFIC team worked with the collaboration of the Valencia City Council, which provided access to traffic management system data, and with the funding of the Valencian Innovation Agency (AVI) under the AVI AirLuisa project.

Reference:
Edgar Lorenzo-Sáez, Javier F. Urchueguía, Miguel García Folgado, Jose-Vicente Oliver-Villanueva, Methodology development for high-resolution monitoring of emissions in urban road traffic systems, Atmospheric Pollution Research, Volume 16, Issue 9, 2025, DOI: https://doi.org/10.1016/j.apr.2025.102600