Polychlorinated Dibenzo-<i>p</i>-dioxins and Dibenzofurans:  Gas-Phase Hydroxyl Radical Reactions and Related Atmospheric Removal

Brubaker, W. Wayne; Hites, Ronald A.

doi:10.1021/es960950d

Cited by 111 publications

(106 citation statements)

References 27 publications

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“…10 Temperature dependency. Temperature-dependent OH-radical reaction rates in air of 14 substances were implemented, based on information in Atkinson (1985) and Brubaker and Hites (1997). 11 pH-dependency.…”

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confidence: 99%

Uncertainty and variability in environmental life-cycle assessment

Huijbregts

2002

Int J LCA

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General introductionIncreased rates of resource depletion, land use, solid waste generation and emissions of pollutants became issues of broad public concern in the beginning of the seventies (Meadows et al., 1972). Unfortunately, most of these problems are still with us today, and some of them have increased substantially (World Resources Institute, 1996). One way to decrease the environmental pressure of human activities is the environmentally improvement of production processes (Reijnders, 1996). In this respect, an important question to be answered is 'how exactly can we measure the environmentally improvement of production processes?' Environmental life-cycle assessment (LCA) aims to answer that question. The first section of this chapter provides an overview of the LCA framework. Although the framework itself is well-established, the application of the framework is in many aspects problematic. A brief overview of the problems associated with the actual implementation of the framework is described in second paragraph. Finally, the aim and the structure of the present thesis is outlined in the third paragraph. § 1.1 Environmental life cycle assessment Environmental life cycle assessment (LCA) is a tool for the assessment of the environmental impact of product systems (Heijungs et al. 1992). It considers the full life cycle of a product from resource extraction to waste disposal. LCA is generally divided into four phases: goal and scope definition, inventory analysis, impact assessment, and interpretation (Figure 1.1; ISO, 1997a).In the goal and scope definition, the aim and the subject of an LCA study are determined and a 'functional unit' is defined. An example of a functional unit is 'the consumption of 100 kg apples' with, for instance, the aim to compare the environmental impacts of different agricultural production processes of apples. In the inventory analysis, for each of the product systems considered data are gathered for all the relevant processes involved in the life cycle. A product system can be considered as a combination of processes needed for the functioning of a product or service. The outcome of the inventory analysis is a list of all extractions of resources and emissions of substances caused by the functional unit for every product system considered, generally disregarding place and time of the extractions and releases. The matrix method can be used to perform the inventory analysis (Heijungs, 1996(Heijungs, , 1997 where i is the vector of environmental interventions, H is the environmental intervention matrix, representing the extractions of resources and emissions of substances per unit process, G is the technology matrix representing the inter-process flows needed for the functioning of the product system, and u is the external supply vector, related to the functional unit. Life cycle impact assessment (LCIA) aims to improve the understanding of the inventory result. Firstly, it is determined which extractions and emissions contribute to which impact categories. An impact category can...

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confidence: 99%

Uncertainty and variability in environmental life-cycle assessment

Huijbregts

2002

Int J LCA

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“…A previous study (Brubaker and Hites, 1997) has indicated that the percentage of PCDD/Fs adsorbed to particles is mainly affected by the vapor pressures of those compounds. The vapor pressures of PCDD/F congeners increase as the gas temperature increases.…”

Section: Vapor/solid Phase Partitioning Of Pcdd/f Congeners In Ambienmentioning

confidence: 98%

Increase of Ambient PCDD/F Concentrations in Northern Taiwan during Asian Dust Storm and Winter Monsoon Episodes

Hsien¹,

Chou

Peng

et al. 2014

Aerosol Air Qual. Res.

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In the spring, Asian dust storms that originate in the deserts of Mongolia and China eventually reach the populated areas of East Asia. The dust storm particles usually contain diverse organic matter and nutrients that may have an adverse effect on human health. In winter, northeast monsoon episodes that originate in the mainland China not only bring cold air but also transport dust and air pollutants to Taiwan over long distances. Based on the above, the presence of persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), in the suspended particles undergoing long-range transport needs to be investigated. In this study, the atmospheric concentrations of PCDD/Fs were monitored and investigated during an Asian dust storm episode and northeast monsoon episode in northern Taiwan. The sampling results indicate that the atmospheric PCDD/Fs observed at two remote sampling sites ranged from 7.46 ± 0.7 to 37. rd December 2008, respectively. Specifically, higher levels of PCDFs (by 70%-76%) were measured in northern Taiwan during these long-range transport periods. As no specific dioxin emission sources exist within 20 km of our sampling sites, the increase in PCDD/F concentrations observed at these two remote sampling sites is likely to be related to the Asian dust storm and northeast monsoon episodes and the pollutants would seem to have come from mainland China.

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“…In addition to QSAR methods, many reaction kinetics with hydroxyl radicals have been measured in the lab for PAHs (Brubaker and Hites 1998b, Kwok et al 1994, Kwok and Atkinson 1995, PCDDlFs Hites 1997, Brubaker andHites 1998b), chlorinated pesticides (Brubaker and Hites 1998a), and PCBs (Anderson and Hites 1996). From these many references and knowledge of the typical hydroxyl radical concentration in an area, the atmospheric half-lives of POPs can be estimated.…”

Section: Atmospheric Reactivitymentioning

confidence: 99%

“…For instance Brubaker and Hites (1997) concluded that the difference seen in the homologue profiles of PCDD/F's between sources and sinks could be due solely to hydroxyl radical attack. Lower chlorinated furans and an increasing contribution from the dioxins with increasing chlorination dominate the source homologue profiles.…”

Section: Persistent Organic Pollutantsmentioning

confidence: 99%

Persistent Organic Pollutants

Qing¹

2001

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Polychlorinated Dibenzo-p-dioxins and Dibenzofurans: Gas-Phase Hydroxyl Radical Reactions and Related Atmospheric Removal

Cited by 111 publications

References 27 publications

Uncertainty and variability in environmental life-cycle assessment

Uncertainty and variability in environmental life-cycle assessment

Increase of Ambient PCDD/F Concentrations in Northern Taiwan during Asian Dust Storm and Winter Monsoon Episodes

Persistent Organic Pollutants

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