| 11. |
- Molnár, Peter, 1967, et al.
(författare)
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Roadside measurements of fine and ultrafine particles at a major road north of Gothenburg
- 2002
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Ingår i: Atmospheric Environment. - 1352-2310 .- 1873-2844. ; 36:25, s. 4115-4123
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Tidskriftsartikel (refereegranskat)abstract
- Particle measurements were conducted at a road site 15 km north of the city of Gothenburg for 3 weeks in June 2000. The size distribution between 10 and 368 nm was measured continuously by using a differential mobility particle sizer (DMPS) system. PM2.5 was sampled on a daily basis with subsequent elemental analysis using EDXRF-spectroscopy. The road is a straight four-lane road with a speed limit of 90 kph. The road passing the site is flat with no elevations where the vehicles run on a steady workload and with constant speed. The traffic intensity is about 20,000 cars per workday and 13,000 vehicles per day during weekends. The diesel fuel used in Sweden is low in sulphur content (< 10 ppm) and therefore the diesel vehicles passing the site contribute less to particle emissions in comparison with other studies. A correlation between PM2.5 and accumulation mode particles (100-368 nm) was observed. However, no significant correlation was found between number concentrations of ultrafine particles (10-100 nm) and PM2.5 or the accumulation mode number concentration. The particle distribution between 10 and 368 nm showed great dependency on wind speed and wind direction, where the wind speed was the dominant factor for ultrafine (10-100nm) particle concentrations. The difference in traffic intensity between workday and weekend together with wind data made it possible to single out the traffic contribution to particle emissions and measure the size distribution. The results presented in combination with previous studies show that both PM2.5 and the mass of accumulation mode particles are bad estimates for ultrafine particles. (C) 2002 Elsevier Science Ltd. All rights reserved.
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| 12. |
- Pommer, Linda, et al.
(författare)
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Development of a NO2 scrubber for accurate sampling of ambient levels of terpenes
- 2002
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Ingår i: Atmospheric Environment. - 1352-2310 .- 1873-2844. ; 36:9, s. 1443-1452
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Tidskriftsartikel (refereegranskat)abstract
- The result of pumping air containing 56 ppb NO2 through a terpene-spiked adsorbent (90–130 ng, 90–100 ml min−1), Tenax TA, for 20 min (1.8–2.0 l) was that 8% of α-pinene, 7% of β-pinene, 21% of Δ3-carene and 5% of limonene were oxidised. In similar experiments with air containing 56 ppb O3, 3% of α-pinene, 4% of β-pinene, 10% of Δ3-carene and 38% of limonene were oxidised. Sampling a mixture of a terpene and NO2 using Tenax TA can give unwanted overestimation of the amount of reaction products from the terpene–NO2 reaction or underestimation of the original terpene levels. A scrubber was needed to reduce the problems caused by interfering reactions on the adsorbent of NO2 and to reduce discrimination of reactive compounds due to their relatively fast decay on the adsorbent. Several chemicals have been tested for their ability of removing NO2 and our objective was to develop a well functioning, reusable, easy to handle, easy manufactured NO2 scrubber. The result of the experiments was a scrubber consisting of two glass fibre filters coated with Na2SO3 assembled in a dust collector. The recovery of the terpenes through the scrubber varied between 75% and 97% at 15–75% relative humidity, and the scrubber is a one-use scrubber due to memory effects. The Na2SO3 scrubber could be stored in room air for at least one month without loosing the capacity of removing NO2.
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| 13. |
- Wingfors, Håkan, et al.
(författare)
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Characterisation and determination of profiles of polycyclic aromatic hydrocarbons in a traffic tunnel in Gothenburg, Sweden
- 2001
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Ingår i: Atmospheric Environment. - 1352-2310 .- 1873-2844. ; 35:36, s. 6361-6369
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations of semi-volatile polycyclic aromatic hydrocarbons (PAHs), hydrocarbons (HCs), particulate matter (PM 1, 2.5 and 10 μm) and total suspended particles (TSPs) were measured in a traffic tunnel in Gothenburg, Sweden. Emission factors (EFs) were also calculated. These variables are assumed to provide good estimates of average vehicle emissions, since all types of vehicle, using all types of fuel, pass through this tunnel. It was shown that the majority of particle-associated PAHs were found on particles with an aerodynamic diameter of <1 μm. The concentrations of PAHs were one order higher in magnitude in air samples from the tunnel than in air samples at two urban locations. However, the PAH profiles of air samples from the tunnel and the urban sites were similar. This was demonstrated using principal component analysis (PCA). Finally, and notably, there was no significant change in the total emissions when the proportion of heavy-duty vehicles (HDVs) increased from 8% to 24%. Previously, diesel vehicles had been found to release larger quantities of PAHs and related substances. Advances in fuel quality, and HDV motor and exhaust system design during the last decade may have contributed to this promising result. However, it was shown, using partial least squares regression to latent structures (PLS), that some of the parameters measured displayed correlations with the proportions of HDVs and light-duty vehicles (LDVs). Concentrations of total HCs, TSPs, dibenzothiopene, phenantrene, anthracene and monomethyl-derivatives of phenantrene and anthracene were all correlated to the proportion of HDVs. The concentrations of naphthalene, some mono- and dimethylnaphthalenes and most large PAHs (with 5–7 fused rings) were correlated to the proportion of LDVs.
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| 14. |
- Agrell, Cecilia, et al.
(författare)
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Polybrominated diphenyl ethers (PBDES) at a solid waste incineration plant I: Atmospheric concentrations
- 2004
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 38:30, s. 5139-5148
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Tidskriftsartikel (refereegranskat)abstract
- In the first of two papers, the atmospheric poly brominated diphenyl ether (PBDE) concentrations at a municipal solid waste incineration (MSW) plant with electronic recycling is compared with that at an industrial urban reference site producing asphalt and concrete. In the second paper, atmospheric deposition and washout behaviour is presented (Atmos. Environ. (2004a)). PBDEs (BDE28, -47, -66, -100, -154, -153, -183, -209) in the gaseous and particulate phase were measured with high resolution in time during the colder parts of the year to minimise the influence of potential historical pollution at the sites through volatilisation. This also means that reported levels are lower compared to other reported data. Results of BDE47 (TetraBDE) and BDE209 (DecaBDE) as representatives of "old" vs. "new" PBDEs as well as SigmaPBDE, excluding BDE209, are presented. Median SigmaPBDE, BDE47 and BDE209 concentration were 6.3, 2.1 and 10.4 pg m(-3) at the MSW and 3.5, 1.7 and 6.5 pg m-3 at the reference site. The total concentrations (gaseous and particulate phase) were significantly higher at the MSW compared to the reference site for SigmaPBDE and BDE47 but not for BDE209. The same results were obtained regarding concentrations in the gaseous phase. Particle concentrations were significantly higher at the MSW for SigmaPBDE, BDE47 and BDE209. Within each site, the gaseous-phase concentration was significantly higher than the particulate-phase concentration except for BDE209 at the MSW. Thus, the proportion of BDE209 detected in the particulate phase was higher at the MSW compared to the reference site. Together with the results of the second paper, we suggest that treatment of waste is presently a source of "old" PBDEs to the environment, whereas the rather similar BDE209 concentrations at the two sites are more a result of proximity to potential diffuse sources.
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| 15. |
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| 16. |
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| 17. |
- Bengtsson, Göran, et al.
(författare)
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Persistence of plasmid RP4 in Pseudomonas putida and loss of its expression of antibiotic resistance in a groundwater microcosm
- 2004
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 36:6, s. 999-1008
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Tidskriftsartikel (refereegranskat)abstract
- We examined the stability of plasmid RN and its expression of antibiotic-resistance genes in suspended and sorbed Pseudomonas putida in aquifer microcosms. Test tubes containing different proportions of sterilized aquifer soil and groundwater were inoculated with bacteria and incubated for up to 26 d. Serial dilutions were made to agar plates with or without antibiotics, to quantify the functional stability of the plasmid. The structural integrity of RN was examined by plasmid extraction, digestion with restriction enzymes, and agarose gel electrophoresis. The plasmid-borne resistance gene expression disappeared in 80-90% of the cells during day 1 of incubation in aquifer soil and then remained at that frequency throughout the experiment. The RP4 plasmid was present in cells without antibiotic-resistance gene expression, indicating that the observed loss of plasmid-encoded activity was most likely due to a reduction in expression of the resistance genes. The increased growth rate in groundwater amended with glucose and phosphate had no significant influence on plasmid loss or antibiotic-resistance expression, suggesting that plasmid loss and antibiotic-resistance expression were independent of the growth rate. Most of the reduction of resistance gene expression was associated with the presence of soil particles, and 70% of the resistance expression was retained in bacteria incubated for 1 d in groundwater alone. Bacteria sorbed to the soil particles had a lower frequency of expression of resistance genes than suspended bacteria, but the difference was not caused by sorbed inorganic or organic chemicals. Resistance gene expression was partly recovered in suspended bacteria after in vitro exposure to the antibiotics and after first isolating on agar without antibiotics and then replica plating to agar containing the antibiotics.
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| 18. |
- Bidleman, TF, et al.
(författare)
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Chiral signatures of chlordanes indicate changing sources to the atmosphere over the past 30 years
- 2004
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 38:35, s. 5963-5970
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Tidskriftsartikel (refereegranskat)abstract
- Chlordane was used as an insecticide for half a century until its withdrawal from the world market in 1997. Trans- and cis-chlordane (TC, CC) are racemic in the technical product, but undergo enantio selective degradation in soil to leave nonracemic residues. In most cases, the (+) enantiomer of TC and the (-) enantiomer of CC are depleted, leading to enantiomer fractions, EF = (+)/[(+) + (-)], that are < 0.500 for TC and > 0.500 for CC. Nonracemic EFs of TC and CC, showing the same degradation preference as soils, were found in 1998-2001 air samples from stations in Arctic Canada and Finland, and on the west coast of Sweden. Environmental samples representing different time periods of chlordane history were also examined in: (a) archived atmospheric deposition samples collected in Sweden, Slovakia and Iceland in 1971-1973, (b) soils from southern Sweden sampled in 2001 and (c) a laminated lake sediment core from the Canadian Arctic representing similar to50 years of accumulation. TC and CC were racemic or nearly so in the historical atmospheric deposition samples and nonracemic in the Swedish soils. The EF of TC in the dated take sediment core decreased from nearly racemic in the past to nonracemic in recent times. These observations suggest that sources of chlordane to the atmosphere have changed over time and are now influenced to a greater extent by emission from soils.
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| 19. |
- Eliasson, Ingegärd, 1961, et al.
(författare)
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Summer nocturnal ozone maxima in Goteborg, Sweden
- 2003
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Ingår i: ATMOSPHERIC ENVIRONMENT. - 1352-2310. ; 37:19, s. 2615-2627
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Tidskriftsartikel (refereegranskat)abstract
- The magnitude and frequency of nocturnal ozone maxima in a high mid-latitude city (Göteborg, Sweden) has been analysed. Nocturnal ozone maxima have been reported from cities in Europe and North America and can be explained by vertical mixing of high ozone concentrations from higher levels or horizontal transportation from rural areas through local and mesoscale wind systems. Data from four summer months (May–August) in 1994 were used to analyse the relative importance of local- and mesoscale wind systems and vertical mixing in Göteborg during clear and calm weather conditions. Results show that nocturnal ozone maxima frequently occur during these conditions, with a magnitude up to 104 μg m−3. The nocturnal ozone maxima were positively correlated to both situations with a well-developed land breeze and situations with vertical mixing. During the period investigated, in total 17 nights with secondary ozone maximum occurred. The majority of the secondary ozone maxima (80%) appeared early in the night, i.e. an ozone increase within the first 3 h after sunset and sometimes even two peaks occurred. Seven of these occasions can be explained by horizontal advection, eight by vertical mixing and five cannot by certainty be explained to be due to horizontal or vertical transportation only. During the measurement period the Swedish guideline of 80 μg m−3 (for 1-h value) was exceeded 55% of the days (i.e. 68 days, 557 h) and 33% of the nights (i.e. 41 nights, 103 h) in the central parts of Göteborg. The results thus show that in Scandinavia nocturnal ozone
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| 20. |
- Fick, Jerker, et al.
(författare)
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Formation of oxidation products in a ventilation system
- 2004
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 38:35, s. 5895-9
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the formation of oxidation products from the ozonolysis of a monoterpene (α-pinene) in an authentic ventilation system. We observed ten products, norpinic acid, pinic acid, glyoxal, methyl glyoxal, norpinonic acid, pinonic acid, a C4 dicarbonyl (C4H6O2), a C5 dicarbonyl (C5H8O2), norpinon aldehyde, and pinon aldehyde. Experiments were conducted at a low (2.0 g m−3) and moderate (8 g m−3) humidity levels. All products but C4 dicarbonyl and norpinon aldehyde were detected at the low humidity level, but only glyoxal, methyl glyoxal, C4 dicarbonyl, norpinon aldehyde and pinon aldehyde were detected at a moderate humidity. Experiments were conducted at low ppb levels (75 ppb ozone and 4 and 10 ppb α-pinene) and with a short reaction time (75 s). Experiments showed that 5–6% of the α-pinene reacted, which was approximately 4–5 times more than predicted by theoretical calculations. This discrepancy suggests a significant contribution from heterogeneous reactions. These oxidation products were formed despite low reactant concentrations and a short reaction time, indicating that the formation of oxidation products likely occurs at ambient levels and in real settings.
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