1. Vertical profiles of lung deposited surface area concentration of particulate matter measured with a drone in a street canyon
- Author
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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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