AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Secondary Aerosol Formation Potential of Gasoline Vehicle Exhaust Under On-road and Laboratory Conditions
PAULI SIMONEN, Joni Kalliokoski, Panu Karjalainen, Miikka Dal Maso, Topi Rönkkö, Sanna Saarikoski, Hilkka Timonen, Matthew Bloss, Athanasios Dimaratos, Leonidas Ntziachristos, Jorma Keskinen, Tampere University of Technology
Abstract Number: 287 Working Group: Combustion
Abstract Light-duty vehicles emit both primary particles and precursor gases that can form secondary particle mass as a result of atmospheric oxidation. The potential of vehicle exhaust to produce secondary mass has been studied in laboratories using large smog chambers and fast oxidation flow reactors. However, the composition of exhaust emissions in real-world driving may significantly differ from those of laboratory driving cycles.
To probe the difference of real-world and laboratory observations, we performed measurements of the secondary mass formation potential of two modern gasoline vehicles. Real-world driving emissions were obtained by vehicle chase measurements, and they were compared to the measurements conducted on a chassis dynamometer for the same vehicles.
The emissions were measured with two ELPIs (Electrical low pressure impactors): one measuring the primary emission and the other measuring the emission aged in TSAR (TUT Secondary Aerosol Reactor), a fast-response oxidation flow tube in which the sample is exposed to ozone and OH radicals. The chemical composition of particles before and after the oxidation flow reactor was measured by an SP-AMS; primary emission particle number concentration was measured using a CPC and a PSM-CPC combination. Gas-phase emissions were measured with CO2 and NOx analyzers. In addition, a PEMS system was deployed during the chase measurements to measure raw exhaust CO2, NOx and CO concentrations.
In this work, we present the results of on-road secondary aerosol formation potential of light-duty gasoline vehicles, and compare the on-road and laboratory results. Especial attention is paid to chemical composition of secondary aerosol, as well as, total secondary particle formation potential in terms of mass.