| 1. |
- Andersen, J. K., et al.
(författare)
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Quantification of Greenhouse Gas Emissions from Windrow Composting of Garden Waste
- 2010
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Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425. ; 39:2, s. 713-724
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Tidskriftsartikel (refereegranskat)abstract
- Microbial degradation of organic wastes entails the production of various gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and carbon monoxide (CO). Some of these gases are classified as greenhouse gases (GHGs), thus contributing to climate change. A study was performed to evaluate three methods for quantifying GHG emissions from central composting of garden waste. Two small-scale methods were used at a windrow composting facility: a static flux chamber method and a funnel method. Mass balance calculations based on measurements of the C content in the in- and out-going material showed that 91 to 94% of the C could not be accounted for using the small-scale methods, thereby indicating that these methods significantly underestimate GHG emissions. A dynamic plume method (total emission method) employing Fourier Transform Infra Red (FTIR) absorption spectroscopy was found to give a more accurate estimate of the GHG emissions, with CO2 emissions measured to be 127 +/- 15% of the degraded C. Additionally, with this method, 2.7 +/- 0.6% and 0.34 +/- 0.16% of the degraded C was determined to be emitted as CH4 and CO. In this study, the dynamic plume method was a more effective tool for accounting for C losses and, therefore, we believe that the method is Suitable for measuring GHG emissions from composting facilities. The total emissions were found to be 2.4 +/- 0.5 kg CH4-C Mg-1 wet waste (ww) and 0.06 +/- 0.03 kg N2O-N Mg-1 ww from a facility treating 15,540 Mg of garden waste yr(-1), or 111 +/- 30 kg CO2-equivalents Mg-1 ww.
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| 2. |
- Börjesson, Gunnar, et al.
(författare)
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A national landfill methane budget for Sweden based on field measurements, and an evaluation of IPCC models
- 2009
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Ingår i: Tellus, Series B: Chemical and Physical Meteorology. - : Stockholm University Press. - 1600-0889 .- 0280-6509. ; 61:2, s. 424-435
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Tidskriftsartikel (refereegranskat)abstract
- Seven Swedish landfills were investigated from 2001 to 2003. On each landfill, a measure of the total methane production was calculated from data on: (1) methane emissions (leakage); (2) methane oxidation and (3) from gas recovery. Methane emissions were determined via a tracer gas (N2O) release-based remote sensing method. N2O and CH4 were measured with an Fourier Transform infrared detector at a distance of more than 1 km downwind from the landfills. Methane oxidation in the landfill covers was measured with the stable carbon isotope method. The efficiency in gas recovery systems proved to be highly variable, but on an average, 51% of the produced landfill gas was captured. A first-order decay model, based on four fractions (waste from households and parks, sludges and industrial waste), showed that the use of a degradable organic carbon fraction (DOCf) value of 0.54, in accordance with the default value for DOCf of 0.50 in the latest IPCC model, gave an emission estimate similar to the official national reports.
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| 3. |
- Börjesson, Gunnar, et al.
(författare)
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Methane oxidation in Swedish landfills qnantified with the stable carbon isotope technique in combination with an optical method for emitted methane
- 2007
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:19, s. 6684-6690
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Tidskriftsartikel (refereegranskat)abstract
- Methane budgets (production = emissions + oxidation + recovery) were estimated for six landfill sites in Sweden. Methane oxidation was measured in downwind plumes with a stable isotope technique (Chariton, J. P., et al., Environ. Sci. TechnoL 1999, 33, 3755-3760.) Positions in plumes for isotope sampling as well as methane emissions were determined with an optical instrument (Fourier Transform InfraRed) in combination with N2O as tracer gas (Galle, B., et al., Environ. Sci. TechnoL 2001, 35,21-25.) Two landfills had been closed for years prior to the measurements, while four were active. Measurements at comparable soil temperatures showed that the two closed landfills had a significantly higher fraction of oxidized methane (38-42% of emission) relative to the four active landfills (4.6-15% of emission). These results highlight the importance of installing and maintaining effective landfill covers and also indicate that substantial amounts of methane escape from active landfills. Based on these results we recommend that the IPCC default values for methane oxidation in managed landfills could be set to 10% for active sites and 20% for closed sites. Gas recovery was found to be highly variable at the different sites, with values from 14% up to 65% of total methane production. The variance can be attributed to different waste management practices.
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| 4. |
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| 5. |
- de Foy, B., et al.
(författare)
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Modelling constraints on the emission inventory and on vertical dispersion for CO and SO2 in the Mexico City Metropolitan Area using Solar FTIR and zenith sky UV spectroscopy
- 2007
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 7, s. 781-801
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Tidskriftsartikel (refereegranskat)abstract
- Emissions of air pollutants in and around urban areas lead to negative health impacts on the population. To estimate these impacts, it is important to know the sources and transport mechanisms of the pollutants accurately. Mexico City has a large urban fleet in a topographically constrained basin leading to high levels of carbon monoxide ( CO). Large point sources of sulfur dioxide (SO2) surrounding the basin lead to episodes with high concentrations. An Eulerian grid model (CAMx) and a particle trajectory model ( FLEXPART) are used to evaluate the estimates of CO and SO2 in the current emission inventory using mesoscale meteorological simulations from MM5. Vertical column measurements of CO are used to constrain the total amount of emitted CO in the model and to identify the most appropriate vertical dispersion scheme. Zenith sky UV spectroscopy is used to estimate the emissions of SO2 from a large power plant and the Popocatepetl volcano. Results suggest that the models are able to identify correctly large point sources and that both the power plant and the volcano impact the MCMA. Modelled concentrations of CO based on the current emission inventory match observations suggesting that the current total emissions estimate is correct. Possible adjustments to the spatial and temporal distribution can be inferred from model results. Accurate source and dispersion modelling provides feedback for development of the emission inventory, verification of transport processes in air quality models and guidance for policy decisions.
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| 6. |
- De Gouw, J. A., et al.
(författare)
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Airborne Measurements of Ethene from Industrial Sources Using Laser Photo-Acoustic Spectroscopy
- 2009
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:7, s. 2437-2442
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Tidskriftsartikel (refereegranskat)abstract
- A laser photoacoustic spectroscopy (LPAS) instrument was developed and used for aircraft measurements of ethene from industrial sources near Houston, Texas. The instrument provided 20 s measurements with a detection limit of less than 0.7 ppbv. Data from this instrument and from the GC-FID analysis of air samples collected in flight agreed within 15% on average. Ethene fluxes from the Mt. Belvieu chemical complex to the northeast of Houston were quantified during 10 different flights. The average flux was 520 +/- 140 kg h(-1) in agreement with independent results from solar occultation flux (SOF) measurements, and roughly an order of magnitude higher than regulatory emission inventories indicate. This study shows that ethene emissions are routinely at levels that qualify as emission upsets, which need to be reported to regional air quality managers.
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| 7. |
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| 8. |
- Johansson, John, 1982, et al.
(författare)
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Emission measurements of alkenes, alkanes, SO2, and NO2 from stationary sources in Southeast Texas over a 5 year period using SOF and mobile DOAS
- 2014
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Ingår i: Journal of Geophysical Research. - : American Geophysical Union (AGU). - 0148-0227 .- 2156-2202 .- 2169-897X. ; 119:4, s. 1973-1991
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Tidskriftsartikel (refereegranskat)abstract
- A mobile platform for flux measurements of VOCs (alkanes and alkenes), SO2, and NO2 emissions using the Solar Occultation Flux (SOF) method and mobile differential optical absorption spectroscopy (DOAS) was used in four different studies to measure industrial emissions. The studies were carried out in several large conglomerates of oil refineries and petrochemical industries in Southeast and East Texas in 2006, 2009, 2011, and 2012. The measured alkane emissions from the Houston Ship Channel (HSC) have been fairly stable between 2006 and 2011, averaging about 11,500kg/h, while the alkene emissions have shown greater variations. The ethene and propene emissions measured from the HSC were 1511kg/h and 878kg/h, respectively, in 2006, while dropping to roughly 600kg/h for both species in 2009 and 2011. The results were compared to annual inventory emissions, showing that measured VOC emissions were typically 5-15 times higher, while for SO2 and NO2 the ratio was typically 0.5-2. AP-42 emission factors were used to estimate meteorological effects on alkane emissions from tanks, showing that these emissions may have been up to 35-45% higher during the studies than the annual average. A more focused study of alkene emissions from a petrochemical complex in Longview in 2012 identified two upset episodes, and the elevation of the total emissions during the measurement period due to the upsets was estimated to be approximately 20%. Both meteorological and upset effects were small compared to the factor of 5-15, suggesting that VOC emissions are systematically and substantially underestimated in current emission inventories.
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| 9. |
- Johansson, John, 1982, et al.
(författare)
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Quantitative measurements and modeling of industrial formaldehyde emissions in the Greater Houston area during campaigns in 2009 and 2011
- 2014
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 119:7, s. 4303-4322
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive Mobile differential optical absorption spectroscopy (DOAS) system with real-time evaluation capability and HCHO detection limit of 3 ppb over 100 m has been developed. The system was operated together with a Solar Occultation Flux system for large-scale vertical flux measurements of HCHO, NO2, SO2, and VOCs in the Houston-Galveston-Brazoria area during two studies, in 2009 (Study of Houston Atmospheric Radical Precursors campaign) and in 2011 (Air Quality Research Program study). Both in 2009 and 2011, HCHO plumes from five separate local sources in Texas City, Mont Belvieu, and Houston Ship Channel (HSC) were repeatedly detected using Mobile DOAS with emissions varying between 6 and 40 kg/h. In many cases significant alkene emissions were detected simultaneously with the HCHO plumes. Furthermore, in 2011 two additional sources were observed in Texas City and in HSC, with 10 kg/h and 31 kg/h HCHO, respectively. A plume chemistry model was applied to 13 cases to investigate whether the detected HCHO was emitted directly from the industries or was produced by photochemical degradation of VOCs. The model results showed that on average 90% of the detected HCHO was of primary origin and the photochemical production contributed more than 10% in only three cases. Based on the repeatability, it is likely that the most significant HCHO sources in the area are included in this study with an overall emission of 120 kg/h. On a regional scale, this emission is small compared to the secondary HCHO formed from oxidation of reactive VOCs emitted from the same industries, estimated to be an order of magnitude higher.
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| 10. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Characterization of Air Toxics and Greenhouse Gas Emission Sources and Their Impacts on Community-Scale Air Quality Levels in Disadvantaged Communities
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Methane (CH4) is an important short-lived climate pollutant and contributes roughly 9 percent to California's statewide GHG emissions. California has passed several climate legislations, including AB 1383 (Lara, 2015-16) and AB 1496 (Thurmond, 2015-16), which require CARB to use the best available scientific and technical methods to monitor and measure high-emission CH4 hotspots within the State, to use the information to update relevant programs and policies, and to implement a climate mitigation program to reduce statewide CH4 emissions by 40 percent below the 2013 levels. Furthermore, certain industrial emissions sources of CH4, such as oil and gas facilities, are known to co-emit air toxics that have adverse health effects, and their impacts are more pronounced in communities near those sources than they are regionally. Therefore, it is important to understand these emissions, and conduct enhanced community-scale monitoring for air toxics in near-source communities, many of which may be disadvantaged. Additionally, scientific studies have suggested that national and statewide CH4 emissions inventories may be underestimated, and real-world emissions measurements may be useful to evaluate source-level emission estimates and understand emission behaviors. The objectives of this research study are to characterize air toxics and GHG emission behavior from a variety of complex emission sources, and to study the impact of these sources on air quality levels in disadvantaged communities. The project utilized a state-of-the-art research-grade mobile monitoring laboratory equipped with advanced monitoring instruments to characterize and quantify the air toxics and GHG emission behavior from complex air pollution sources, as well as their air pollution impacts on nearby communities. Through four regional campaigns across California, the project measured facility-level emissions of CH4, alkanes, benzene, BTEX (benzene, toluene, ethylbenzene and xylene), ammonia (NH3), and sulfur and nitrogen oxides (SOX and NOX) from a variety of sources, including refineries, petrochemical facilities, oil storage, port activities, landfills, oil and gas production and dairy farms, and tracked the air pollution impact of the emission plumes in neighboring communities. This study found that the observed emissions, which are representative of emissions at a single point in time, were greater than inventory factors and models, representative of overall averages, for many of the volatile organic compounds (VOC). Alkane emissions from five large refinery areas in the Bay Area were on average 2.5 times the reported emission, and CH4 emissions were roughly 3 times the reported emissions, while total NOX emissions were comparable to the inventory estimates. Similarly, alkane and CH4 emissions from oil and gas fields in the San Joaquin Valley, which accounts for more than 70 percent of California's oil and gas production capacity, were 10 and 2 times higher than production-based emission factors, respectively. On the other hand, CH4 and NH3 emissions from roughly 20 dairy farms were 50 percent and 100 percent higher than annual emission factor, respectively, some of which were due to diurnal variations. These discrepancies suggest more work is needed to ascertain whether these point-in-time measurements are representative of annual averages, and if emissions are indeed higher than standard methods suggest. The measurements in the Richmond community showed VOC concentrations dominated by alkanes from the port area. Community-scale ground-level concentrations of BTEX were on average low in all studies. The research study demonstrated the use of advanced techniques for facility-wide emission measurements and community monitoring of air toxics, and suggests that a combination of mobile and fixed continuous measurements may provide useful information to understand source emissions, and their impacts on communities. The source-level emission data may be useful to understand emissions from complex emission sources (including large point sources, distributed emission sources, area sources). The community-scale measurement effort will provide the ability to conduct community-scale air toxics measurements in real-time, with information on air pollution hotspots in various disadvantaged communities and useful screening information to identify potential sources for prioritizing air pollution mitigation efforts. https://ww3.arb.ca.gov/research/single-project.php?row_id=67028
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| 11. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Measurements of fugitive emissions of vocs from stationary sources using the SOF method - Standardization efforts and results from recent studies in California
- 2019
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Ingår i: AQM 2019 - Air Quality Measurement Methods and Technology Conference 2019.
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Konferensbidrag (refereegranskat)abstract
- The Solar Occultation Flux (SOF) method is used to screen and quantify VOC emissions from industrial conglomerates down to sub-areas in individual plants, such as a few tank process area or water treatment areas. The SOF method has been applied in several larger campaigns in both Europe and in the US (Mexico City 2006, Texas 2006/2009/2011/2012; Le Havre 2008, Rotterdam 2008/2010 and Antwerp 2010/2016, California 2013/20T5, Tianjin China 2016) and in more than 100 individual plant surveys over the world. The technique has been validated by comparison to other methods and tracer gas releases and it typically has an uncertainty of 30%, mostly due to uncertainties in the wind field. In the various campaign studies it has been found that the measured emissions obtained with SOF are 3–10 times higher than the reported emission obtained by calculations. The SOF method is Best Available Technology in Europe for quantitative measurements of diffuse emissions from refineries and the chemical sector. The technique is presently being standardized by the European CEN.
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| 12. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Measurements of industrial emissions of alkenes in Texas using the solar occultation flux method
- 2010
-
Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 115
-
Tidskriftsartikel (refereegranskat)abstract
- Solar occultation flux (SOF) measurements of alkenes have been conducted to identify and quantify the largest emission sources in the vicinity of Houston and in SE Texas during September 2006 as part of the TexAQS 2006 campaign. The measurements have been compared to emission inventories and have been conducted in parallel with airborne plume studies. The SOF measurements show that the hourly gas emissions from the large petrochemical and refining complexes in the Houston Ship Channel area and Mount Belvieu during September 2006 corresponded to 1250 +/- 180 kg/h of ethene and 2140 +/- 520 kg/h of propene, with an estimated uncertainty of about 35%. This can be compared to the 2006 emission inventory value for ethene and propene of 145 +/- 4 and 181 +/- 42 kg/h, respectively. On average, for all measurements during the campaign, the discrepancy factor is 10.2(+ 8,-5) for ethene and 11.7(+ 7,-4) for propene. The largest emission source was Mount Belvieu, NE of the Houston Ship Channel, with ethene and propene emissions corresponding to 440 +/- 130 kg/h and 490 +/- 190 kg/h, respectively. Large variability of propene was observed from several petrochemical industries, for which the largest reported emission sources are flares. The SOF alkene emissions agree within 50% with emissions derived from airborne measurements at three different sites. The airborne measurements also provide support to the SOF error budget.
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| 13. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Methane emissions from industrial activities using drones
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Innovative drone-based methods have been developed to map and quantify methane leakages from various industrial activities, such as refineries, Liquified Natural Gas (LNG) terminals, landfills, and water treatment facilities. These methods use a high-speed, high-sensitivity laser sensor and were validated through controlled gas releases. They were also compared to a ground-based infrared absorption-based technique. This initiative is supported by the Swedish Governmental Agency for Innovation Systems (Vinnova) and aligns with UN Sustainable Development Goals 9, 11, and 13. The goal is to reduce methane emissions significantly, aiding Sweden in achieving net-zero greenhouse gas emissions by 2045. Accurate measurements enable effective, targeted, and trackable measures to minimize emissions, resulting in a rapid positive climate impact. The project has led to the development of two distinct drone-based methods: the wall approach and the tracer approach. The wall approach measures gas concentrations across the entire cross-section of the plume, whereas the tracer approach measures the ratio of leaking gas to source gas. Depending on the source's size, one approach may be preferred over the other, with the tracer method being more suitable for point sources and the wall approach for larger sources. The custom-designed drone in this project, provided and operated by Gerdes Solution. is equipped with a high-sensitivity laser sensor and has a flight duration of about 12 minutes while carrying a 3 kg payload. This limitation presents a challenge when conducting wall measurements, which require approximately 25 minutes of flight time for the studied sources. Due to the drone's limited flight time, it necessitates landing and battery replacement, which complicates the process and limits the number of repeat measurements. In future endeavors, employing a drone with a longer flight duration would be advantageous. In total, the study detected about 220 kg/h of methane emissions and 3 kg/h of nitrous oxide emissions, equivalent to an emission rate of about 7 tons/h of carbon dioxide. The emissions were dominated by the water treatment plant and landfills, with relatively little coming from the refinery and LNG plant. However, the wall measurements in thus study serve as demonstrations of how the technique can be used and do not provide a comprehensive picture of the actual emissions from the individual sites; this would require more statistical data in terms of repeat measurements and measurement days. It is shown that drone measurements using the new high sensitivity laser is a valuable tool for mapping methane concentrations from various types of industrial sources, which are challenging to investigate today due to diffuse emissions, large dimensions, and complex geometries. The validation studies show that both the wall approach and controlled tracer releases can be used to quantify emissions, achieving an accuracy of up to 10 % for a simple, single, source. However, in the real measurement situation, the wall approach may be difficult to execute due to practical challenges like flying restrictions and the need for spatially dense data that can be interpolated to a homogenous grid and repeated measurements. In several cases, when the drone had to fly relatively close to the plumes, downwind of large buildings in complex and turbulent wind fields, the wall approach yielded large variability in the resulting flux. It is hence evident that the wall approach requires a thorough understanding of the measurement situation, and that repeated measurements are needed, at different distances from the source and in varying wind directions. The tracer approach was therefore preferred choice for obtaining emission rates in this study, although it is challenging to carry out representative tracer releases for larger sources and for cases when the measurements are performed near to the source, and in this case the wall approach is preferred. It was also shown that the drone-based tracer approach is advantageous to the ground based since it is then easier to capture the full plume.
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| 14. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Mobile column measurements of CO in megacities
- 2004
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Ingår i: Proceedings of the XVIII Quadrennial Ozone Symposium, June 2004, Kos, Greece, ed. C. Zerefos, II. ISBN/ISSN: 960-630-103-6. ; , s. 613-
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Konferensbidrag (refereegranskat)
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| 15. |
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| 16. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Quantification of Gas Emissions from Refineries, Gas Stations, Oil Wells and Agriculture using Optical Solar Occultation Flux and Tracer Correlation Methods
- 2016
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Ingår i: AGU Fall meeting San Francisco Dec 2016.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Industrial volatile organic compound (VOC) emissions may contribute significantly to ozone formation. In order to investigate how much small sources contribute to the VOC concentrations in the Los Angeles metropolitan area a comprehensive emission study has been carried out on behalf of the South Coast Air Quality Management District (SCAQMD). VOC emissions from major sources such as refineries, oil wells, petrol stations oil depots and oil platforms were measured during September and October 2015 using several unique optical methods, including the Solar Occultation Flux method (SOF) and tracer correlation technique based on extractive FTIR and DOAS combined with an open path multi reflection cell. In addition, measurements of ammonia emissions from farming in Chino were demonstrated. The measurements in this study were quality assured by carrying out a controlled source gas release study and side by side measurements with several other techniques. The results from the field campaign show that the emissions from the above mentioned sources are largely underestimated in inventories with potential impact on the air quality in the Los Angeles metropolitan area. The results show that oil and gas production is a very significant VOC emission source. In this presentation the techniques will be discussed together with the main results from the campaign including the quality assurance work.
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| 17. |
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| 18. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Quantification of stack emissions from marine vessels
- 2016
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Ingår i: Air and Waste Management Association - Air Quality Measurement Methods and Technology Conference 2016. - 9781510822535 ; , s. 416-421
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Konferensbidrag (refereegranskat)abstract
- Ship emission data from fixed and mobile platforms were obtained during 5 weeks in October and November of 2015. The main objective was to study the "real life" ship emissions of gases and particles in different modes of ship operation in the vicinity of the harbor, from open sea to berth. These emissions can be used to calculate the impact of shipping activities on air quality in the LA basin. Since ships are supposed to run on low sulfur fuel it is interesting how the new low sulfur fuel impacts also emissions of particles, in addition to sulfur. During the project we found several ships running on high sulfur fuel. During the presentation we will describe the method and show example of data from the project.
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| 19. |
- Mellqvist, Johan, 1965, et al.
(författare)
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Remote Quantification of Stack Emissions from Marine Vessels
- 2016
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Ingår i: A&WMA’s 109th Annual Conference & Exhibition, New Orleans, Louisiana, June 2016. - 1052-6102. ; 1, s. 579-583
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Konferensbidrag (refereegranskat)abstract
- Stationary and mobile (on-vessel) measurements of ship specific emission factors and total emission were carried out in the port of Los Angeles and Long Beach. The measurement techniques developed to characterize individual ship emissions were presented. The data were obtained with a zenith DOAS technique for NO 2 and "in-situ" sniffer technique for SO 2 , NO x , CO 2 , and particulates. The measured particle properties corresponded to particulate number, particulate mass, and black and organic carbon. Total emissions of NO 2 from the harbors were also obtained through mobile optical zenith sky measurements. The potential VOC emissions were investigated when fueling the ships and other VOC sources in the harbor using techniques like the Solar Occultation Flux technique. This is an abstract of a paper presented at the A & WMA's 109th Annual Conference & Exhibition (New Orleans, LA 6/20-23/2016).
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| 20. |
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| 21. |
- Monster, J. G., et al.
(författare)
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Quantifying methane emission from fugitive sources by combining tracer release and downwind measurements - A sensitivity analysis based on multiple field surveys
- 2014
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 34:8, s. 1416-1428
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Tidskriftsartikel (refereegranskat)abstract
- Using a dual species methane/acetylene instrument based on cavity ring down spectroscopy (CRDS), the dynamic plume tracer dispersion method for quantifying the emission rate of methane was successfully tested in four measurement campaigns: (1) controlled methane and trace gas release with different trace gas configurations, (2) landfill with unknown emission source locations, (3) landfill with closely located emission sources, and (4) comparing with an Fourier transform infrared spectroscopy (FTIR) instrument using multiple trace gasses for source separation. The new real-time, high precision instrument can measure methane plumes more than 1.2 km away from small sources (about 5 kg h(-1)) in urban areas with a measurement frequency allowing plume crossing at normal driving speed. The method can be used for quantification of total methane emissions from diffuse area sources down to 1 kg per hour and can be used to quantify individual sources with the right choice of wind direction and road distance. The placement of the trace gas is important for obtaining correct quantification and uncertainty of up to 36% can be incurred when the trace gas is not co-located with the methane source. Measurements made at greater distances are less sensitive to errors in trace gas placement and model calculations showed an uncertainty of less than 5% in both urban and open-country for placing the trace gas 100 m from the source, when measurements were done more than 3 km away. Using the ratio of the integrated plume concentrations of tracer gas and methane gives the most reliable results for measurements at various distances to the source, compared to the ratio of the highest concentration in the plume, the direct concentration ratio and using a Gaussian plume model. Under suitable weather and road conditions, the CRDS system can quantify the emission from different sources located close to each other using only one kind of trace gas due to the high time resolution, while the FTIR system can measure multiple trace gasses but with a lower time resolution.
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| 22. |
- Mönster, Jacob, et al.
(författare)
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Quantification of methane emissions from 15 Danish landfills using the mobile tracer dispersion method
- 2015
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 35, s. 177-186
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Tidskriftsartikel (refereegranskat)abstract
- Whole-site methane emissions from 15 Danish landfills were assessed using a mobile tracer dispersion method with either Fourier transform infrared spectroscopy (FTIR), using nitrous oxide as a tracer gas, or cavity ring-down spectrometry (CRDS), using acetylene as a tracer gas. The landfills were chosen to represent the different stages of the lifetime of a landfill, including open, active, and closed covered landfills, as well as those with and without gas extraction for utilisation or flaring. Measurements also included landfills with biocover for oxidizing any fugitive methane. Methane emission rates ranged from 2.6 to 60.8kgh -1 , corresponding to 0.7-13.2gm -2 d -1 , with the largest emission rates per area coming from landfills with malfunctioning gas extraction systems installed, and the smallest emission rates from landfills closed decades ago and landfills with an engineered biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41-81%. Landfills where shredder waste was deposited showed significant methane emissions, with the largest emission from newly deposited shredder waste. The average methane emission from the landfills was 154tonsy -1 . This average was obtained from a few measurement campaigns conducted at each of the 15 landfills and extrapolating to annual emissions requires more measurements. Assuming that these landfills are representative of the average Danish landfill, the total emission from Danish landfills were calculated at 20,600tonsy -1 , which is significantly lower than the 33,300tonsy -1 estimated for the national greenhouse gas inventory for 2011.
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| 23. |
- Rivera, Claudia, 1976, et al.
(författare)
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Quantification of NO2 and SO2 emissions from the Houston Ship Channel and Texas City industrial areas during the 2006 Texas Air Quality Study
- 2010
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 115
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Tidskriftsartikel (refereegranskat)abstract
- In August-September 2006, as part of the Second Texas Air Quality Study, NO2 and SO2 emissions from the Houston Ship Channel and Texas City industrial areas were quantified using mobile mini-differential optical absorption spectroscopy instruments. The measured NO2 emissions from the Houston Ship Channel and Texas City industrial areas were 2542 and 452 kg h(-1), respectively, yielding NOx emissions 70% and 43%, respectively, above the reported inventory values. Quantified SO2 emissions from the Houston Ship Channel area were 1749 kg h(-1) and were found to be 34% above the values reported in the inventory. Short-term variability of NO2 and SO2 emissions was found at the Houston Ship Channel. On 31 August 2006, a plume was detected at the HSC during three consecutive measurements, yielding a HCHO flux of 481 kg h(-1). This event has been mainly attributed to photochemical production.
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| 24. |
- Samuelsson, Jerker, 1972, et al.
(författare)
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Quantification of VOC emissions using tracer dispersion, Mobile Extractive FTIR (MEFTIR) and Mobile Whitecell-DOAS (MWDOAS)
- 2015
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Ingår i: Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA. - 1052-6102. - 9781510815582 ; 3, s. 2310-2317
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Konferensbidrag (refereegranskat)abstract
- The application of Mobile Extractive FTIR and Mobile Whitecell Differential Optical Absorption Spectroscopy to establish VOC emission factors for tank filling operations and for discharge of petroleum products to trucks and vessels is described. An example of VOC emissions related to discharge of gasoline to trucks at a depot, which was connected to vapor recovery unit, is presented. Discharge of gasoline to ships was found to have an alkane (CH4 emission factor of about 5x10-5 kg emitted VOC/kg discharged product, comparable to the corresponding for trucks. This is an abstract of a paper presented at the 108th AWMA Annual Conference and Exhibition (Raleigh, NC 6/22-25/2015).
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| 25. |
- Samuelsson, Jerker, 1972, et al.
(författare)
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Quantifying industrial emissions by measuring infrared intensity of solar spectra - the SOF technique
- 2012
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Ingår i: Solid-State and Organic Lighting, SOLED 2012, Eindhoven, Netherlands, 11-14 November 2012. - Washington, D.C. : OSA. - 2162-2701. - 9781557529527
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Konferensbidrag (refereegranskat)abstract
- Optical techniques attract increasing interest and usage for quantifying industrial emissions. The Solar Occultation Flux (SOF) method has been applied in numerous international surveys. Technical aspects and survey findings of general interest are discussed.
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