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AHMA: estimating vehicle emissions under real driving conditions

The Project AHMA (Ajoneuvokannan Hiukkaspäästöjen arviointi Mittauksilla todellisissa Ajotilanteissa ja ikäytyskammioissa; in English: Estimation of particulate emissions from the vehicle fleet by measurements under real driving conditions and in aging chambers), funded by Jane and Aatos Erkko’s Foundation, aims to understand the particle emissions from light-duty road vehicles operating in a Finnish environment, e.g. in the wide range of outdoor temperatures. The work includes statistical analysis of data obtained from measuring the emissions of hundreds of individual vehicles, detailed investigations of emissions related to their wintertime use and expanding the understanding on the exhaust-related secondary aerosol formation in different environments.

AHMA Partners include Tampere University (Aerosol Physics Laboratory) and University of Eastern Finland (Aerosol Physics Group). Currently there are 6 people working in the project, more during summer periods when some research assistants join the crew.

Through AHMA, we aim to provide emission factors for different technologies and parametrization of the emissions related to e.g. ambient conditions. As a novel finding, we observed that fuel-operated auxiliary heaters can be a major source of emissions during cold periods. A short article of this emission source was recently published (Karjalainen et al., Fuel-Operated Auxiliary Heaters Are a Major Additional Source of Vehicular Particulate Emissions in Cold Regions, Atmosphere, 2021,

The ACCC Flagship’s central objectives are climate change and deteriorating air quality. Studying particle emission sources and quantifying their emissions, such as with AHMA, provide tools for tackling these issues.

We are always open to new collaborations. Get in touch with the AHMA project via Panu Karjalainen (TAU) and Santtu Mikkonen (UEF).

ACCC’s motto is “Clean air. Safe climate”. We need to achieve these as soon as possible, everywhere.

Figure: On-road chase measurement in Kuopio with Aerosol and Trace gas Mobile Laboratory (ATMo-Lab) in progress. Emissions from real-world driving in cold weather (even below -20⁰C) were studied, with the emphasis on quantifying the impact of engine preheating on the emissions. ATMo-Lab was packed with aerosol instruments capable of measuring several key properties of aerosols, such as particle number concentration, size distribution, chemical composition, formation potential of secondary aerosol and concentrations of several gases. Photographer: Markus Nikka