If you’re a frequent reader of our blog, you already know that we’re deeply invested in air quality — particularly when it comes to the impact of transportation. Whether it’s engine emissions, field measurements, lab studies, or targeted campaigns, we’ve done it all.
If you’re new here, you’ve arrived at an exciting time! We’re taking things to the next level — and this time, we’re going European. We’re proud to be part of the Horizon 2020 Project Net4Cities, which focuses on monitoring transport-related emissions — including noise — to support city stakeholders in their efforts to implement zero-pollution pathways.
In a nutshell
The EU Horizon Project Net4Cities addresses the pressing challenge of transport-related emissions, which significantly contribute to air pollution and noise pollution in urban areas, impacting both the environment and public health. To address the complex environmental impacts of traffic, Net4Cities is building a real-time monitoring network in eleven European cities, including Zurich. This network collects high-quality, comparable data from major transport hubs — roads, airports, and ports — using a combination of established methods and cutting-edge technologies. In addition to tracking conventional pollutants, the project also targets emerging pollutants that are increasingly recognized for their health and environmental risks. Together with source apportionment techniques, this comprehensive approach enables more accurate emissions allocation and supports the design of targeted, evidence-based mitigation strategies.
Net4Cities follows a transdisciplinary approach, bringing together research institutions, city authorities, and policymakers to design practical and scalable solutions, including nature-based approaches. A core feature of the project is the Net4Cities Studio, a web-based platform that visualizes real-time environmental data and offers actionable insights to support informed decision-making. Since its launch in January 2024, the project has progressed from initial planning and communication setup to the installation of measurement devices and the development of the Net4Cities Studio.
Not just another emission monitoring network – here’s what sets Net4Cities apart
Co-creation approach
From the very beginning, Net4Cities has worked closely with local stakeholders to ensure that collected data and research findings are practical and actionable. This collaborative approach bridges the gap between scientific insights and real-world implementation, supporting the development of targeted measures for improved air quality and reduced noise pollution.
Ultrafine particle measurements
Traditional air quality monitoring often focuses on PM10 and PM2.5, measuring particle mass. However, these methods tend to overlook the smallest particles in the nanometer range, which pose significant health risks by penetrating deep into the lungs and even entering the bloodstream. Net4Cities addresses this gap by measuring ultrafine particles (UFPs) at 33 sites across participating cities. This includes particle number counts at 24 sites and surface area at 33 sites, creating a broad database for better assessment of UFPs.
Monitoring ammonia, nitrogen oxides, and climate-active gases:
Fuel combustion releases various gaseous emissions that harm the environment and contribute to climate change. Net4Cities systematically measures ammonia and nitrogen dioxide using passive samplers across all eleven partner cities for one year. Additionally, monthly air samples are analyzed to determine concentrations of methane, CO₂, carbon monoxide, and volatile organic compounds (VOCs).
Linking traffic counts, noise, and pollution data:
A standout feature of Net4Cities is its ability to combine traffic counts, noise measurements, and pollutant concentrations. This integrated approach provides a comprehensive picture of traffic-related environmental impacts, revealing how factors such as fleet composition and traffic systems influence emissions. By applying consistent measurement methods across all eleven partner cities, the project also highlights regional differences and their effects.
What’s our contribution?
As part of the Net4Cities project, we are contributing in two key areas: coordinating activities in Zurich and leading pioneering LDSA measurements to assess ultrafine particles.
Representing the city of Zurich:
We coordinate all measurement activities in Zurich and serve as a link between the project consortium, local authorities, and other stakeholders. In this role, we make sure that the specific interests and needs of the Zurich region are represented throughout the project.
Leading LDSA measurements:
A central focus of our work lies in measuring the lung-deposited surface area (LDSA) — the total surface area of ultrafine particles capable of penetrating deep into the lungs. Although this metric may seem abstract at first, it is directly linked to the health risks posed by ultrafine particles, as numerous in-vivo and in-vitro studies have shown in recent years.
We at METENVIA bring extensive experience in this field. In close collaboration with our long-time partners at naneos, pioneers in manufacturing reliable and easy-to-handle LDSA sensors, we are deploying 33 LDSA sensors across all Net4Cities measurement locations. Starting this spring, these devices will collect continuous data over a period of three years, offering valuable insights into the distribution and behavior of ultrafine particles and how they relate to other environmental parameters such as particle number, black carbon, and VOCs.
With this data, we aim to close critical knowledge gaps and provide a solid scientific foundation for effective, evidence-based measures to improve air quality.
As part of Net4Cities, additional measurements are being carried out at this site, including LDSA, ammonia, and monthly air sampling for gas analysis.
What’s next?
We’re currently in the rollout phase — deploying all measurement devices and launching the coordinated offline sampling campaigns. At the same time, development of the Net4Cities Studio is in full swing. Our goal: to make real-time environmental data publicly accessible before the end of the year.
Stay tuned right here on the blog or follow us on LinkedIn — via METENVIA and Net4Cities — to keep up with the latest updates and insights.
P.S. If you’re interested in aviation-related ultrafine particle emissions, check out the recent report from our colleagues at OSTLUFT on UFP measurements near Zurich Airport.
Funding acknowledgements
