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8 results on '"Matti Irjala"'

1. Using the Multicomponent Aerosol FORmation Model (MAFOR) to Determine Improved VOC Emission Factors in Ship Plumes

Author

Lea Fink, Matthias Karl, Volker Matthias, Andreas Weigelt, Matti Irjala, and Pauli Simonen

Subjects
VOC emission factor, ship emissions, aerosol box model, Chemical technology, TP1-1185
Abstract

International shipping’s particulate matter primary emissions have a share in global anthropogenic emissions of between 3% and 4%. Ship emissions of volatile organic compounds (VOCs) can play an important role in the formation of fine particulate matter. Using an aerosol box model for the near-plume scale, this study investigated how the changing VOC emission factor (EF) for ship engines impacts the formation of secondary PM2.5 in ship exhaust plumes that were detected during a measurement campaign. The agreement between measured and modeled particle number size distribution was improved by adjusting VOC emissions, in particular of intermediate-, low-, and extremely low-volatility compounds. The scaling of the VOC emission factor showed that the initial emission factor, based on literature data, had to be multiplied by 3.6 for all VOCs. Information obtained from the box model was integrated into a regional-scale chemistry transport model (CTM) to study the influence of changed VOC ship emissions over the Mediterranean Sea. The regional-scale CTM run with adjusted ship emissions indicated a change in PM2.5 of up to 5% at the main shipping routes and harbor cities in summer. Nevertheless, overall changes due to a change in the VOC EF were rather small, indicating that the size of grid cells in CTMs leads to a fast dilution.

Published
2024
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4. Vertical profiles of lung deposited surface area concentration of particulate matter measured with a drone in a street canyon

Author

Heino Kuuluvainen, Hilkka Timonen, Joel Kuula, Topi Rönkkö, Anssi Järvinen, Matti Irjala, Jarkko V. Niemi, Miikka Dal Maso, Jorma Keskinen, Mikko Poikkimäki, Tampere University, Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, and Research area: Aerosol Physics

Subjects
Diffusion (acoustics), 010504 meteorology & atmospheric sciences, Health, Toxicology and Mutagenesis, Wind, 010501 environmental sciences, Toxicology, Atmospheric sciences, 114 Physical sciences, 01 natural sciences, Altitude, Exponential decay, Dispersion (water waves), Finland, Vehicle Emissions, 0105 earth and related environmental sciences, Canyon, Air Pollutants, geography, geography.geographical_feature_category, General Medicine, Models, Theoretical, Particulates, Pollution, Drone, Aerosol, Environmental science, Particulate Matter, Environmental Monitoring
Abstract

The vertical profiles of lung deposited surface area (LDSA) concentration were measured in an urban street canyon in Helsinki, Finland, by using an unmanned aerial system (UAS) as a moving measurement platform. The street canyon can be classified as an avenue canyon with an aspect ratio of 0.45 and the UAS was a multirotor drone especially modified for emission measurements. In the experiments of this study, the drone was equipped with a small diffusion charge sensor capable of measuring the alveolar LDSA concentration of particles. The drone measurements were conducted during two days on the same spatial location at the kerbside of the street canyon by flying vertically from the ground level up to an altitude of 50 m clearly above the rooftop level (19 m) of the nearest buildings. The drone data were supported by simultaneous measurements and by a two-week period of measurements at nearby locations with various instruments. The results showed that the averaged LDSA concentrations decreased approximately from 60 μm2/cm3 measured close to the ground level to 36–40 μm2/cm3 measured close to the rooftop level of the street canyon, and further to 16–26 μm2/cm3 measured at 50 m. The high-resolution measurement data enabled an accurate analysis of the functional form of vertical profiles both in the street canyon and above the rooftop level. In both of these regions, exponential fits were used and the parameters obtained from the fits were thoroughly compared to the values found in literature. The results of this study indicated that the role of turbulent mixing caused by traffic was emphasized compared to the street canyon vortex as a driving force of the dispersion. In addition, the vertical profiles above the rooftop level showed a similar exponential decay compared to the profiles measured inside the street canyon. The high-resolution vertical profiles of lung deposited surface area obtained in this study are valuable with respect to exposure estimations, urban planning, and urban air quality models. acceptedVersion

Published
2018
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