Aerosol dynamics and dispersion of radioactive particles

In the event of a failure of a nuclear power plant with release of radioactive material into the atmosphere, dispersion modelling is used to understand how the released radioactivity is spread. For the dispersion of particles, Lagrangian particle dispersion models (LPDMs) are commonly used, in which model particles, representing the released material, are transported through the atmosphere. These model particles are usually inert and undergo only first-order processes such as dry deposition and simplified wet deposition along the path through the atmosphere. Aerosol dynamic processes including coagulation, condensational growth, chemical interactions, formation of new particles and interaction with new aerosol sources are usually neglected in such models. The objective of this study is to analyse the impact of these advanced aerosol dynamic processes if they were to be included in LPDM simulations for use in radioactive preparedness. In this investigation, a fictitious failure of a nuclear power plant is studied for three geographically and atmospherically different sites. The incident was simulated with a Lagrangian single-trajectory box model with a new simulation for each hour throughout a year to capture seasonal variability of meteorology and variation in the ambient aerosol. (a) We conclude that modelling of wet deposition by incorporating an advanced cloud parameterization is advisable, since it significantly influence simulated levels of airborne and deposited activity including radioactive hotspots, and (b) we show that inclusion of detailed ambient-aerosol dynamics can play a large role in the model result in simulations that adopt a more detailed representation of aerosol–cloud interactions. The results highlight a potential necessity for implementation of more detailed representation of general aerosol dynamic processes into LPDMs in order to cover the full range of possible environmental characteristics that can apply during a release of radionuclides into the atmosphere

Hourly Particle Number Size Distribution (PNSD) measurements at Melpitz (2008)

One year of hourly Particle Number Size Distribution (PNSD) measurements at three different location with different air masses. Different kinds of Mobility Particle Size Spectrometers, MPSS has been used for the measurements. --- Melpitz (2008), Central European background, Neo (2012), Clean Remote background Zeppelin (2010), Marine background --- Melpitz: Lat 51.53 deg, Long 12.93 deg Neo: Lat 36.83 deg, long 21.70 deg Zeppelin: lat 78.90, long 11.86 de

Hourly Particle Number Size Distribution (PNSD) measurements at Neo (2012)

One year of hourly Particle Number Size Distribution (PNSD) measurements at three different location with different air masses. Different kinds of Mobility Particle Size Spectrometers, MPSS has been used for the measurements. --- Melpitz (2008), Central European background, Neo (2012), Clean Remote background Zeppelin (2010), Marine background --- Melpitz: Lat 51.53 deg, Long 12.93 deg Neo: Lat 36.83 deg, long 21.70 deg Zeppelin: lat 78.90, long 11.86 de

Detection of Sindbis and Inkoo Virus RNA in Genetically Typed Mosquito Larvae Sampled in Northern Sweden

Introduction: Mosquito-borne viruses have a widespread distribution across the globe and are known to pose serious threats to human and animal health. The maintenance and dissemination of these viruses in nature are driven through horizontal and vertical transmission. In the temperate climate of northern Sweden, there is a dearth of knowledge on whether mosquito-borne viruses that occur are transmitted transovarially. To gain a better understanding of mosquito-borne virus circulation and maintenance, mosquito larvae were sampled in northern Sweden during the first and second year after a large outbreak of Ockelbo disease in 2013 caused by Sindbis virus (SINV). Materials and Methods: A total of 3123 larvae were sampled during the summers of 2014 and 2015 at multiple sites in northern Sweden. The larvae were homogenized and screened for viruses using RT-PCR and sequencing. Species identification of selected larvae was performed by genetic barcoding targeting the cytochrome C oxidase subunit I gene. Results and Discussion: SINV RNA was detected in mosquito larvae of three different species, Ochlerotatus (Oc.) communis, Oc. punctor, and Oc. diantaeus. Inkoo virus (INKV) RNA was detected in Oc. communis larvae. This finding suggested that these mosquitoes could support transovarial transmission of SINV and INKV. Detection of virus in mosquito larva may serve as an early warning for emerging arboviral diseases and add information to epidemiological investigations before, during, and after outbreaks. Furthermore, our results demonstrated the relevance of genetic barcoding as an attractive and effective method for mosquito larva typing. However, further mosquito transmission studies are needed to ascertain the possible role of different mosquito species and developmental stages in the transmission cycle of arboviruses