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- Levin, M., et al.
(författare)
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Limitations in the Use of Unipolar Charging for Electrical Mobility Sizing Instruments: A Study of the Fast Mobility Particle Sizer
- 2015
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Ingår i: Aerosol Science and Technology. - : Informa UK Limited. - 1521-7388 .- 0278-6826. ; 49:8, s. 556-565
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Tidskriftsartikel (refereegranskat)abstract
- A comparison between three different types of particle sizing instruments (fast mobility particle sizer, FMPS; electrical low pressure impactor, ELPI; and scanning mobility particle sizer, SMPS) and one condensation particle counter (CPC) was made to compare instrument response in terms of size distributions and number concentration. Spherical oil droplets in 39 different sizes, with geometric mean diameter (GMD) ranging from 50nm to 820nm, were used as test particles. Furthermore, a characterization of the FMPS unipolar charger behavior was made to analyze the measured size distributions and number concentrations. The results show that all three sizing-instruments agree well for particle sizes below 200nm, both in terms of size and number concentration, but the FMPS deviates clearly when particle sizes exceed 200nm. Above this, the FMPS underestimates the particle size throughout the remainder of the size range, with an apparent upper limit for GMD of 300nm. It also estimates a higher particle number concentration as compared to the other instruments. Analysis of the 22 FMPS electrometer currents and calculation of average number of charges per particle show a diameter dependence of response of [GRAPHICS] for the FMPS unipolar charger. The resulting calculated electrical mobility showed a minimum in mobility for spherical particles at 577nm, which indicates an interfering range of particles above the measurement range, but below the cut-off of the inlet pre-separator (1 mu m). The study concludes that particle distributions with a true GMD above 200nm cannot be measured reliably with the FMPS.
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- Andersen, M. H. G., et al.
(författare)
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Exposure to Air Pollution inside Electric and Diesel-Powered Passenger Trains
- 2019
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:8, s. 4579-4587
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Tidskriftsartikel (refereegranskat)abstract
- Diesel-powered trains are used worldwide for passenger transport. The present study aimed to assess air pollution concentrations in passenger cars from diesel and electric trains. Personal exposure monitoring (6-7 h per day) was carried out for 49 days on diesel and 22 days on electric trains. Diesel trains had higher concentrations of all the assessed air pollution components. Average increases (and fold differences) in passenger cars of diesel trains compared with electric trains were for ultrafine particles 212 000 particles/cm(3) (35-fold), black carbon 8.3 mu g/m(3) (6-fold), NOx 316 mu g/m(3) (8-fold), NO2 38 mu g/m(3) (3-fold), PM2.5 34 mu g/m(3) (2-fold), and benzo(a)pyrene 0.14 mu g/m(3) (6-fold). From time-series data, the pull and push movement modes, the engine in use, and the distance to the locomotive influenced the concentrations inside the diesel trains. In conclusion, concentrations of all air pollutants were significantly elevated in passenger cars in diesel trains compared to electric trains.
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- Andersen, M. H. G., et al.
(författare)
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Health effects of exposure to diesel exhaust in diesel-powered trains
- 2019
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Ingår i: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 16:21
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundShort-term controlled exposure to diesel exhaust (DE) in chamber studies have shown mixed results on lung and systemic effects. There is a paucity of studies on well-characterized real-life DE exposure in humans. In the present study, 29 healthy volunteers were exposed to DE while sitting as passengers in diesel-powered trains. Exposure in electric trains was used as control scenario. Each train scenario consisted of three consecutive days (6h/day) ending with biomarker samplings.ResultsCombustion-derived air pollutants were considerably higher in the passenger carriages of diesel trains compared with electric trains. The concentrations of black carbon and ultrafine particles were 8.5g/m(3) and 1.2-1.8x10(5) particles/cm(3) higher, respectively, in diesel as compared to electric trains. Net increases of NOx and NO2 concentrations were 317g/m(3) and 36g/m(3). Exposure to DE was associated with reduced lung function and increased levels of DNA strand breaks in peripheral blood mononuclear cells (PBMCs), whereas there were unaltered levels of oxidatively damaged DNA, soluble cell adhesion molecules, acute phase proteins in blood and urinary excretion of metabolites of polycyclic aromatic hydrocarbons. Also the microvascular function was unaltered. An increase in the low frequency of heart rate variability measures was observed, whereas time-domain measures were unaltered.ConclusionExposure to DE inside diesel-powered trains for 3days was associated with reduced lung function and systemic effects in terms of altered heart rate variability and increased levels of DNA strand breaks in PBMCs compared with electric trains.Trial registrationClinicalTrials.Gov (NCT03104387). Registered on March 23rd 2017
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