Journal Article

Developing Emission Factors from Real-World Emissions of Euro VI Urban Diesel, Diesel-Hybrid, and Compressed Natural Gas Buses

Gaie-Levrel, François, Ntziachristos, Leonidas, Sanchez, Olivier, Debert, Christophe, Perdikopoulos, Michail, Deville Cavellin, Laure, Arfire, Adrian, Marfaing, Hélène, Karageorgiou, Traianos, Joly, Fabrice, Vigneron, Jeremy

2025

Overview

Urban transportation is a key contributor to air pollution in cities. While urban buses impact air quality, they also promote sustainable mobility. In the Paris region, buses account for approximately 4% of traffic emissions. This study addresses the gap in real-world emissions data for Euro VI diesel, diesel-hybrid, and compressed natural gas (CNG) urban buses by developing speed-dependent emission factors for CO, NOX, SPN23, and energy consumption. An optimized methodology was applied to portable emission measurement system data collected from 28 urban buses across various routes in the Paris metropolitan area, capturing emissions across different speeds and traffic conditions. Results showed that diesel buses emit around 2 g/km of NOx at low speeds, compared to 1.4 g/km for diesel hybrids and 0.6 g/km for CNG. CO emissions reached approximately 1 g/km for CNG and 0.5 g/km for diesel, while SPN23 emissions for all powertrains were in the order of 1012 particles/km. The resulting speed-dependent emission factors were incorporated into COPERT version 5.8, the European Union’s standard emission inventory software, improving the inventory accuracy. The findings underscore the need for additional reductions in air pollutant emissions to meet Euro 7 standards and provide a robust framework for improving air quality management.

• Publisher: MDPI AG,MDPI
• Subject: Air pollution / Air quality / Air quality management / Automotive emissions / bus / Buses / Buses (vehicles) / Carbon dioxide / Carbon monoxide emissions / Compressed gas / Compressed natural gas / COPERT / Diesel / emission factors / Emission inventories / Emission measurements / Emission standards / Emissions / Energy consumption / Environment / Environmental aspects / Environmental Sciences / Greenhouse gases / Hybrids / inventories / Metropolitan areas / Natural gas / Natural gas vehicles / Nitrogen compounds / Outdoor air quality / Pollutants / portable emission measurement systems (PEMSs) / Powertrain / Public transportation / Quality management / Quality standards / real driving emissions (RDE) / Suburban areas / Temperature / Traffic / Urban air quality / Urban transportation / Vehicle emissions