Publications by authors named "Athanasios Mamakos"

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future combustion engine vehicle technology may emit large amounts of sub-23 nm particles. The Horizon 2020 funded project DownToTen (DTT) developed a sampling and measurement method to characterize particle emissions in this currently unregulated size range.

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The particle number (PN) emissions of vehicles equipped with particulate filters are low. However, there are technologies that can have high PN levels, especially below the currently lower regulated particle size of 23 nm. Sub-23-nm particles are also considered at least as dangerous as the larger ultrafine particles.

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On-board portable emissions measurement systems (PEMS) are part of the type approval, in-service conformity, and market surveillance aspects of the European exhaust emissions regulation. Currently, only solid particles >23 nm are counted, but Europe will introduce a lower limit of 10 nm. In this study, we evaluated a 10-nm prototype portable system comparing it with laboratory systems measuring diesel, gasoline, and CNG (compressed natural gas) vehicles with emission levels ranging from approximately 2 × 10 to 2 × 10 #/km.

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The carbonaceous fraction of airborne particulate matter (PM) is of increasing interest due to the adverse health effects they are linked to. Its analytical ascertainment on a molecular level is still challenging. Hence, analysis of carbonaceous fractions is often carried out by determining bulk parameters such as the overall content of organic compounds (OC) and elemental carbon (EC) as well as the total carbon content, TC (sum of OC and EC), however, no information about the individual substances or substance classes, of which the single fractions consist can be obtained.

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The Dekati mass monitor (OMM) is an instrument which measures the mass concentration of airborne particles in real time by combining aerodynamic and mobility size particle classification. In this study, we evaluate the performance of the DMM by sampling exhaust from five engines and vehicles of different technologies in both steady-state and transient tests. DMM results are found higher than the filter-based particulate matter (PM) by 39 +/- 24% (range stands for +/- one standard deviation) for 62 diesel tests conducted in total and 3% and 14% higher, respectively, in two gasoline tests.

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