Speaker
Description
Current emission factors used in the Dutch implementation of CNOSSOS are based on measurements from campaigns conducted approximately 17 and 30 years ago. Road vehicles have changed in the meantime, and these values are no longer representative for the current vehicle fleet in the Netherlands. To address this, new measurements were conducted in 2020 to determine updated emission values for road vehicles. These new values were incorporated into the national calculation method in 2024. No new emission factors for CNOSSOS were derived at that time. To keep the national method and CNOSSOS aligned we have derived new emission factors for CNOSSOS based on these more recent measurements. In this paper, we describe the methodology used to derive the new emission factors. We also analyse the impact of using these updated values on noise maps produced in the upcoming round of noise mapping, compared to the previous round. The effects vary by vehicle speed: at low speeds, emission values are substantially lower than before, while at high speeds, they are slightly higher. For context, we also compare these new Dutch CNOSSOS emission factors with those used in other countries for noise mapping.