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- Lunder Halvorsen, Helene, et al.
(author)
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Spatial variability and temporal changes of POPs in European background air
- 2023
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 299
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Journal article (peer-reviewed)abstract
- Concentration data on POPs in air is necessary to assess the effectiveness of international regulations aiming to reduce the emissions of persistent organic pollutants (POPs) into the environment. POPs in European background air are continuously monitored using active- and passive air sampling techniques at a limited number of atmospheric monitoring stations. As a result of the low spatial resolution of such continuous monitoring, there is limited understanding of the main sources controlling the atmospheric burdens of POPs across Europe. The key objectives of this study were to measure the spatial and temporal variability of concentrations of POPs in background air with a high spatial resolution (n = 101) across 33 countries within Europe, and to use observations and models in concert to assess if the measured concentrations are mainly governed by secondary emissions or continuing primary emissions. Hexachlorobenzene (HCB) was not only the POP detected in highest concentrations (median: 67 pg/m3), but also the only POP that had significantly increased over the last decade. HCB was also the only POP that was positively correlated to latitude. For the other targeted POPs, the highest concentrations were observed in the southern part of Europe, and a declining temporal trend was observed. Spatial differences in temporal changes were observed. For example, γ-HCH (hexachlorocyclohexane) had the largest decrease in the south of Europe, while α-HCH had declined the most in central-east Europe. High occurrence of degradation products of the organochlorine pesticides and isomeric ratios indicated past usage. Model predictions of PCB-153 (2,2’,4,4’,5,5’-hexachlorobiphenyl) by the Global EMEP Multi-media Modelling System suggest that secondary emissions are more important than primary emissions in controlling atmospheric burdens, and that the relative importance of primary emissions are more influential in southern Europe compared to northern Europe. Our study highlights the major advantages of combining high spatial resolution observations with mechanistic modelling approaches to provide insights on the relative importance of primary- and secondary emission sources in Europe. Such knowledge is considered vital for policy makers aiming to assess the potential for further emission reduction strategies of legacy POPs.
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| 2. |
- Shatalov, Victor, et al.
(author)
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Tracing the origin of dioxins in Baltic air using an atmospheric modeling approach
- 2012
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In: Atmospheric Pollution Research. - 1309-1042. ; 3:4, s. 408-416
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Journal article (peer-reviewed)abstract
- Previous work has concluded that the sources of dioxins to the Baltic Sea are dominated by atmospheric deposition. Here, we investigate whether current emission estimates can explain Baltic air levels and deposition fluxes of four selected 2,3,7,8-substituted PCDD/F congeners using an atmospheric modeling approach. The EMEP (European Monitoring and Evaluation Programme) database of emissions for dioxins was used to provide inputs to the selected model (MSCE-POP model) and model predicted levels were compared with measurements of dioxins in air and deposition fluxes at three monitoring stations in Sweden. The model underestimated air concentrations between a factor of 5 and 30, with the level of agreement depending on congener, monitoring station and, importantly, with the compass sector from which the contaminated air mass had arrived. Additional model simulations were undertaken in which emissions were enlarged in some selected areas to optimize agreement between model predictions and measurements. A novel emission adjustment approach is used in an attempt to identify source regions where emissions were in error. The emission adjustment approach improved the agreement between model predictions and measurements for 60% of the measurements within a factor of 3 of model predicted concentrations. However, the agreement was still relatively poor when air masses originated from the SSE and SSW. The model adjustment procedure gives an indication of the magnitude of error in exiting emission estimates, but due to the poor quality of existing emission databases and few quality air monitoring data it is not currently possible to use the emission adjustment approach to accurately identify source regions of error. The approach presented here is promising, however, and could be applied to other substances where better emission and monitoring data are available. (C) Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License.
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