| 171. |
- Li, Yingming, et al.
(författare)
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Study of PCBs and PBDEs in King George Island, Antarctica, using PUF passive air sampling
- 2012
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Ingår i: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 51, s. 140-145
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Tidskriftsartikel (refereegranskat)abstract
- Polyurethane foam (PUF)-disk based passive air samplers were deployed in King George Island, Antarctica, during the austral summer of 2009-2010, to investigate levels, distributions and potential sources of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Antarctic air. The atmospheric levels of Sigma indicator PCBs and Sigma(14) PBDEs ranged from 1.66 to 6.50 pg m(-3) and from 0.67 to 2.98 pg m(-3), respectively. PCBs homologue profiles were dominated by di-PCBs, tri-PCBs and tetra-PCBs, whereas BDE-17 and BDE-28 were the predominant congeners of PBDEs, which could be explained by long-range atmospheric transport processes. However, the sampling sites close to the Antarctic research stations showed higher atmospheric concentrations of PCBs and PBDEs than the other sites, reflecting potential local sources from the Antarctic research stations. The non-Aroclor congener PCB-11 was found in all the air samples, with air concentrations of 3.60-31.4 pg m(-3) (average 15.2 pg m(-3)). Comparison between the results derived from PUF-disk passive air sampling and high-volume air sampling validates the feasibility of using the passive air samplers in Antarctic air. To our knowledge, this study is the first employment of PUF-disk based passive air samplers in Antarctic atmosphere.
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| 172. |
- Lindgren, Magnus, et al.
(författare)
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Analysis of unregulated emissions from an off-road diesel engine during realistic work operations
- 2011
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 45, s. 5394-5398
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Tidskriftsartikel (refereegranskat)abstract
- Emissions from vehicle diesel engines constitute a considerable share of anthropogenic emissions of pollutants, including many non-regulated compounds such as aromatic hydrocarbons and alkenes. One way to reduce these emissions might be to use fuels with low concentrations of aromatic hydrocarbons, such as Fischer–Tropsch (F–T) diesels. Therefore this study compared Swedish Environmental Class 1 diesel (EC1) with the F–T diesel fuel Ecopar™ in terms of emissions under varied conditions (steady state, controlled transients and realistic work operations) in order to identify factors influencing emissions in actual operation. Using F–T diesel reduced emissions of aromatic hydrocarbons, but not alkenes. Emissions were equally dependent on work operation character (load, engine speed, occurrence of transients) for both fuels. There were indications that the emissions originated from unburnt fuel, rather than from combustion products
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| 173. |
- Lunder Halvorsen, Helene, et al.
(författare)
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Spatial variability and temporal changes of POPs in European background air
- 2023
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 299
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Tidskriftsartikel (refereegranskat)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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| 174. |
- Lundin, Lisa, et al.
(författare)
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The effect of developing nations' municipal waste composition on PCDD/PCDF emissions from open burning
- 2013
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Ingår i: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 79, s. 433-441
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Tidskriftsartikel (refereegranskat)abstract
- Open burning tests of municipal waste from two countries, Mexico and China, showed composition-related differences in emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDDs/PCDFs). Twenty-six burn tests were conducted, comparing results from two laboratory combustion facilities. Waste was shredded to isolate composition-specific effects from those due to random waste orientation. Emissions ranged from 5 to 780 ng toxic equivalent/kg carbon burned (ng TEQ (kg C-b)(-1)) with an average of 140 ng TEQ (kg C-b)(-1) (stdev = 170). The waste from Mexico (17 ng TEQ (kg C-b)(-1)) had a statistically lower average emission factor than waste from China (240 ng TEQ (kg C-b)(-1). This difference was attributed primarily to waste composition differences, although one time-integrated combustion quality measure, Delta CO/Delta CO2, showed statistical significance between laboratories. However, waste composition differences were far more determinant than which laboratory conducted the tests, illustrated using both statistical techniques and comparison of cross-over samples (wastes tested at both facilities). Comparison of emissions from previous waste combustion tests in Sweden and the U.S.A, showed emission factors within the range of those determined for Mexico and China waste. For laboratory-scale combustion, existing emission factors and test methodologies are generally applicable to both developed and developing countries.
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| 175. |
- Malmqvist, Ebba, et al.
(författare)
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Assessing ozone exposure for epidemiological studies in Malmo and Umea, Sweden
- 2014
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 94, s. 241-248
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Tidskriftsartikel (refereegranskat)abstract
- Ground level ozone [ozone] is considered a harmful air pollutant but there is a knowledge gap regarding its long term health effects. The main aim of this study is to develop local Land Use Regression [LUR] models that can be used to study long term health effects of ozone. The specific aim is to develop spatial LUR models for two Swedish cities, Umea and Malmo, as well as a temporal model for Malmo in order to assess ozone exposure for long term epidemiological studies. For the spatial model we measured ozone, using Ogawa passive samplers, as weekly averages at 40 sites in each study area, during three seasons. This data was then inserted in the LUR-model with data on traffic, land use, population density and altitude to develop explanatory models of ozone variation. To develop the temporal model for Malmo, hourly ozone data was aggregated into daily means for two measurement stations in Malmo and one in a rural area outside Malmo. Using regression analyses we inserted meteorological variables into different temporal models and the one that performed best for all three stations was chosen. For Malmo the LUR-model had an adjusted model R-2 of 0.40 and cross validation R-2 of 0.17. For Umea the model had an adjusted model R-2 of 0.67 and cross validation adjusted R-2 of 0.48. When restricting the model to only including measuring sites from urban areas, the Malmo model had adjusted model R-2 of 0.51 (cross validation adjusted R-2 0.33) and the Umea model had adjusted model R-2 of 0.81 (validation adjusted R-2 of 0.73). The temporal model had adjusted model R-2 0.54 and 0.61 for the two Malmo sites, the cross validation adjusted R-2 was 0.42. In conclusion, we can with moderate accuracy, at least for Umea, predict the spatial variability, and in Malmo the temporal variability in ozone variation. (C) 2014 The Authors. Published by Elsevier Ltd.
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| 176. |
- Markowicz, Pawel, et al.
(författare)
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Improving the indoor air quality by using a surface emissions trap
- 2015
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 106, s. 376-381
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Tidskriftsartikel (refereegranskat)abstract
- The surface emissions trap, an adsorption cloth developed for reducing emissions of volatile organic compounds and particulate matter from surfaces while allowing evaporation of moisture, was used to improve the indoor air quality of a school building with elevated air concentrations of 2-ethyl-1-hexanol. An improvement of the perceived air quality was noticed a few days after the device had been attached on the PVC flooring. In parallel, decreased air concentrations of 2-ethyl-1-hexanol were found as well as a linear increase of the amounts of the same compound adsorbed on the installed cloth as observed up to 13 months after installation. Laboratory studies revealed that the performance of the device is not affected by differences in RH (35-85%), temperature (30-40 degrees C) or by accelerated aging simulating up to 10 years product lifetime, and, from a blinded exposure test, that the device efficiently blocks chemical odors. This study suggests that the device may represent a fast and efficient means of restoring the indoor air quality in a building e.g. after water damage leading to irritating and potentially harmful emissions from building material surfaces indoors. (C) 2014 Elsevier Ltd. All rights reserved.
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| 177. |
- Marshall, John
(författare)
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Can tree-ring chemistry be used to monitor atmospheric nanoparticle contamination over time?
- 2022
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 268
-
Tidskriftsartikel (refereegranskat)abstract
- Industrial activities and human population growth have resulted in an unprecedented increase in the release of particulate matter (PM) into the environment. Nanoparticle (NP) contamination is widespread and affects all terrestrial and aquatic ecosystems, putting humans and environment at risk. Several studies on the impact of PM and NPs on human health have been conducted over the past two decades, but their effects on plants are still poorly understood. What happens to them in forest ecosystems and trees has yet to be explored. In this paper, we review the literature on the capacity of trees to be used as bioindicators and proxy recorders of past air pollution events. Current research indicates that ultrafine particles can be taken up and translocated to different parts of a tree by physical and chemical processes, as we present studies of plant uptake and translocation processes of NPs in trees. Tree-ring chemistry, i.e., dendrochemistry, has been successfully used to reconstruct trace metal deposition from a variety of sources of pollution, including cars, metal refineries and coal burning. The use of dendrochemistry in environmental monitoring seems promising particularly given the presence of recent development of analytical tools, and is likely to provide useful data on atmospheric NP contamination that could not be obtained from any other source. However, still relatively little is known about the dynamic relationships between NPs and trees. We therefore discuss what future dendrochemical research is needed to make den-drochemical analyses as accurate as possible for monitoring atmospheric nanoparticle contamination over time.
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| 178. |
- Martin Ngwabie, Ngwa, et al.
(författare)
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Effects of animal activity and air temperature on methane and ammonia emissions from a naturally ventilated building for dairy cows
- 2011
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 45, s. 6760-6768
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of how different factors affect gas emissions from animal buildings can be useful for emission prediction purposes and for the improvement of emission abatement techniques. In this study, the effects of dairy cow activity and indoor air temperature on gas emissions were examined. The concentrations of CH(4), NH(3), CO(2) and N(2)O inside and outside a dairy cow building were measured continuously between February and May together with animal activity and air temperature. The building was naturally ventilated and had a solid concrete floor which sloped towards a central urine gutter. Manure was scraped from the floor once every hour in the daytime and once every second hour at night into a partly covered indoor pit which was emptied daily at 6 a.m. and at 5 p.m. Gas emissions were calculated from the measured gas concentrations and ventilation rates estimated by the CO(2) balance method. The animal activity and emission rates of CH(4) and NH(3) showed significant diurnal variations with two peaks which were probably related to the feeding routine. On an average day, CH(4) emissions ranged from 7 to 15 g LU(-1) h(-1) and NH(3) emissions ranged from 0.4 to 1.5 g LU(-1) h(-1) (1 LU = 500 kg animal weight). Mean emissions of CH(4) and NH(3) were 10.8 g LU(-1) h(-1) and 0.81 g LU(-1) h(-1), respectively. The NH(3) emissions were comparable to emissions from tied stall buildings and represented a 4% loss in manure nitrogen. At moderate levels, temperature seems to affect the behaviour of dairy cows and in this study where the daily indoor air temperature ranged from about 5 up to about 20 degrees C, the daily activity of the cows decreased with increasing indoor air temperature (r = -0.78). Results suggest that enteric fermentation is the main source of CH(4) emissions from systems of the type in this study, while NH(3) is mainly emitted from the manure. Daily CH(4) emissions increased significantly with the activity of the cows (r = 0.61) while daily NH(3) emissions increased significantly with the indoor air temperatures (r = 0.66). Daily CH(4) emissions were negatively correlated to the indoor air temperature (r = -0.84). This suggests that increased daily indoor air temperatures due to seasonal changes may bring about decreased animal activity which may decrease the release of CH(4) from dairy cows. Finally, changes in daily NH(3) emissions were influenced more by the indoor air temperature than by the activity of the cows. (C) 2011 Elsevier Ltd. All rights reserved.
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| 179. |
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| 180. |
- Masala, Silvia, et al.
(författare)
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Determination of semi-volatile and particle-associated polycyclic aromatic hydrocarbons in Stockholm air with emphasis on the highly carcinogenic dibenzopyrene isomers
- 2016
-
Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 140, s. 370-380
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations of polycyclic aromatic hydrocarbons (PAHs) have been determined in the gaseous phase and in various particulate matter (PM) size fractions at different locations in and outside of Stockholm, Sweden, representative of street level, urban and rural background. The focus has been on the seldom determined but highly carcinogenic dibenzopyrene isomers (DBPs) dibenzo[a,I]pyrene, dibenzo [a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene. PAHs with 3 rings were found to be mainly associated with the vapor phase (>90%) whereas PAHs with 5-6 rings were mostly associated with particulate matter (>92%) and the 4-ringed PAHs partitioned between the two phases. PAH abundance was determined to be in the order street level > urban background > rural background with the PM10 street level 2010 mean of benzo[a]pyrene (B[a]P) reaching 0.24 ng/m(3), well below the EU annual limit value of 1 ng/m(3). In addition, higher PAH concentrations were found in the sub-micron particle fraction (PM1) as compared to the super -micron fraction (PM1-10) with the abundance in PM1 varying between 57 and 86% of the total PAHs. The B[a]P equivalent concentrations derived for DB[a,l]P and total DBPs exceeded 1-2 and 2-4 times, respectively, that of B[a]P at the four sampling sites; therefore underestimation of the cancer risk posed by PAHs in air could be made if the DBPs were not considered in risk assessment using the toxic equivalency approach, whilst the high correlation (p < 0.001) found in the relative concentrations supports the use of B[a]P as a marker substance for assessment of the carcinogenic risk associated to PAHs. However, the big difference in concentration ratios of B[a]P and the DBPs between the present study and some literature data calls for further research to evaluate the temporal and spatial invariance of the B[a]P/DBP ratios.
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