| 1. |
- Tang, L., et al.
(författare)
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Estimation of the long-range transport contribution from secondary inorganic components to urban background PM10 concentrations in south-western Sweden during 1986-2010
- 2014
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 89, s. 93-101
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of long-range transported (LRT) to urban background PM10 concentrations was investigated from a long-term view from 1986 to 2010. Regional air concentrations of sulphate (SO42-), nitrate (NO3-), and ammonium (NH4+) were used as a sum (C-ion) to investigate the contribution from these ions to the LRT PM10 concentrations at an urban background site in Gothenburg, Sweden. Utilizing backwards trajectory analysis, the LRT contribution from C-ion to the urban background PM10 concentrations (LRTCion) was estimated for six unique transport pathways and related source areas. Air masses transported over eastern Europe, UK/North Sea/Denmark and the vicinity of Scandinavia were associated with high C-ion concentrations observed in Gothenburg. For each pathway, multiple linear models based on the C-ion concentrations were used to estimate LRTCion and PM10 at the urban background site. The performances of the multiple linear models were satisfying with R-2 between estimated and observed annual mean PM10 concentrations of 0.81 during the monitoring years 1990-2010. The models were able to describe the main features of the day-to-day average PM10 concentrations, but underestimated high level values. The annual estimated LRTCion contribution decreased from 7 +/- 2 mu g/m(3) for 1986-2000 to 5 +/- 1 mu g/m(3) for 2001-2010. The higher LRTCion contribution was related to the transport cluster from eastern Europe, UK/North Sea/Denmark and the vicinity of South Scandinavia. (C) 2014 Elsevier Ltd. All rights reserved.
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| 2. |
- Wierzbicka, Aneta, et al.
(författare)
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Detailed diesel exhaust characteristics including particle surface area and lung deposited dose for better understanding of health effects in human chamber exposure studies
- 2014
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 86, s. 212-219
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Tidskriftsartikel (refereegranskat)abstract
- Several diesel exhaust (DE) characteristics, comprising both particle and gas phase, recognized as important when linking with health effects, are not reported in human chamber exposure studies. In order to understand effects of DE on humans there is a need for better characterization of DE when performing exposure studies. The aim of this study was to determine and quantify detailed DE characteristics during human chamber exposure. Additionally to compare to reported DE properties in conducted human exposures. A wide battery of particle and gas phase measurement techniques have been used to provide detailed DE characteristics including the DE particles (DEP) surface area, fraction and dose deposited in the lungs, chemical composition of both particle and gas phase such as NO, NO2, CO, CO2, volatile organic compounds (including aldehydes, benzene, toluene) and polycyclic aromatic hydrocarbons (PAHs). Eyes, nose and throat irritation effects were determined. Exposure conditions with PM1 (<1 mu m) mass concentration 280 mu g m(-3), number concentration 4 x 10(5) cm(-3) and elemental to total carbon fraction of 82% were generated from a diesel vehicle at idling. When estimating the lung deposited dose it was found that using the size dependent effective density (in contrast to assuming unity density) reduced the estimated respiratory dose by 132% by mass. Accounting for agglomerated structure of DEP prevented underestimation of lung deposited dose by surface area by 37% in comparison to assuming spherical particles. Comparison of DE characteristics reported in conducted chamber exposures showed that DE properties vary to a great extent under the same DEP mass concentration and engine load. This highlights the need for detailed and standardized approach for measuring and reporting of DE properties. Eyes irritation effects, most probably caused by aldehydes in the gas phase, as well as nose irritation were observed at exposure levels below current occupational exposure limit values given for exhaust fumes. Reporting detailed DE characteristics that include DEP properties (such as mass and number concentration, size resolved information, surface area, chemical composition, lung deposited dose by number, mass and surface) and detailed gas phase including components known for their carcinogenic and irritation effect (e.g. aldehydes, benzene, PAHs) can help in determination of key parameters responsible for observed health effects and comparison of chamber exposure studies. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
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