Atmospheric oxidation of fluoroalcohols initiated by ·OH radical in the presence of water and mineral dusts: Mechanism, kinetics, and risk assessment

2021 ◽  
Author(s):  
Feng-Yang Bai ◽  
Ming-Shuai Deng ◽  
Mei-Yan Chen ◽  
Lian Kong ◽  
Shuang Ni ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Environmental Risks ◽  
Atmospheric Oxidation ◽  
Oh Radical ◽  
Mineral Dusts

The transport and formation of fluorinated compounds are greatly significant due to their possible environmental risks. In this work, the ·OH-mediated degradation of CF3CF2CF2CH2OH and CF3CHFCF2CH2OH in the existence of...

GIS and Remote Sensing in Environmental Risk Assessment

2011 ◽  
pp. 840-847 ◽  
Author(s):  
X. Mara Chen
Keyword(s):  
Remote Sensing ◽  
Risk Assessment ◽  
Environmental Protection ◽  
Environmental Risk ◽  
Environmental Risk Assessment ◽  
Global Economy ◽  
Environmental Risks ◽  
Human Environment ◽  
Gis And Remote Sensing ◽  
Risk Assessment And Management

The existence, well-being, and sustainable development of the global economy hinges upon the state of the earth’s environment. Effective environmental risk assessment and management issues have become increasingly important. With the ever-growing global population and expanding economic development, we consume more natural resources, produce more waste, and develop more areas into the regions that are prone to environmental risks. Although humans have interacted with the environment for thousands of years, environmental risk assessment and management is only a recent research undertaking. As the industrialization has made the human-environment interactions more dynamic and complex, the increased environmental risks have propelled and compelled people to use technologies for identifying and solving problems. The earliest global environmental applications of remote sensing and GIS technologies began in the 1960s, particularly marked by the successful launch of the TIROS- 1, the first meteorological satellite, and the development of computer-based geographic information systems (GIS). The story Silent Spring (Carson, 1962) awoke the public’s environmental consciousness and promoted the public demands for governments to set up environmental protection policies and research priorities. The birth of the U.S. Environmental Protection Agency (EPA) in 1970 set the stage for modern environment risk assessment. The launch of the LANDSAT program in 1972 created a new way for monitoring global land use and land cover changes (Foley, 1999; Goward, Masek, Williams, Irons, & Thompson, 2001).

Theoretical investigation on atmospheric oxidation of fluorene initiated by OH radical

2019 ◽  
Vol 669 ◽  
pp. 920-929 ◽  
Author(s):  
Zhezheng Ding ◽  
Yayi Yi ◽  
Qingzhu Zhang ◽  
Tao Zhuang
Keyword(s):  
Theoretical Investigation ◽  
Atmospheric Oxidation ◽  
Oh Radical

Atmospheric oxidation mechanism of polyfluorinated sulfonamides — A quantum chemical and kinetic study

2013 ◽  
Vol 91 (6) ◽  
pp. 472-478 ◽  
Author(s):  
Xiaoyan Sun ◽  
Lei Ding ◽  
Qingzhu Zhang ◽  
Wenxing Wang
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Single Point ◽  
Oxidation Mechanism ◽  
Basis Set ◽  
Atmospheric Oxidation ◽  
Oh Radicals ◽  
Oh Radical ◽  
Orbital Theory ◽  
Point Energy

Polyfluorinated sulfonamides (FSAs, F(CF2)nSO2NR1R2) are present in the atmosphere and may serve as the source of perfluorocarboxylates (PFCAs, CF3(CF2)nCOO–) in remote locations through long-range atmospheric transport and oxidation. Density functional theory (DFT) molecular orbital theory calculations were carried out to investigate OH radical-initiated atmospheric oxidation of a series of sulfonamides, F(CF2)nSO2NR1R2 (n = 4, 6, 8). Geometry optimizations of the reactants as well as the intermediates, transition states, and products were performed at the MPWB1K level with the 6-31G+(d,p) basis set. Single-point energy calculations were carried out at the MPWB1K/6-311+G(3df,2p) level of theory. The OH radical-initiated reaction mechanism is given and confirms that the OH addition to the sulfone double bond producing perfluoroalkanesulfonic acid directly cannot occur in the general atmosphere. Canonical variational transition-state (CVT) theory with small curvature tunneling (SCT) contribution was used to predict the rate constants. The overall rate constants were determined, k(T) (N-EtFBSA + OH) = (3.21 × 10−12) exp(–584.19/T), k(T) (N-EtFHxSA + OH) = (3.21 × 10−12) exp(–543.24/T), and k(T) (N-EtFOSA + OH) = (2.17 × 10−12) exp(–504.96/T) cm3 molecule−1 s−1, over the possible atmospheric temperature range of 180–370 K, indicating that the length of the F(CF2)n group has no large effect on the reactivity of FSAs. Results show that the atmospheric lifetime of FSAs determined by OH radicals will be 20–40 days, which agrees well with the experimental values (20–50 days), 20 thus they may contribute to the burden of perfluorinated pollution in remote regions.

scholarly journals COMPARISON OF DIFFERENT FUZZY AHP METHODOLOGIES IN RISK ASSESSMENT

2017 ◽  
Vol 2 ◽  
pp. 137 ◽  
Author(s):  
Andrejs Radionovs ◽  
Oleg Uzhga-Rebrov
Keyword(s):  
Risk Assessment ◽  
Decision Making ◽  
Fuzzy Ahp ◽  
Multiple Criteria Decision Making ◽  
Environmental Risks ◽  
Assessment Process ◽  
Analytic Hierarchy ◽  
Risk Assessment Process ◽  
Risks Assessment ◽  
Hierarchy Process

Being able to evaluate risks is an important task in many areas of human activity: economics, ecology, etc. Usually, environmental risk assessment is carried out on the basis of multiple and sometimes conflicting factors. Using multiple criteria decision-making (MCDM) methodology is one of the possible ways to solve the problem. Methodologies of analytic hierarchy process (AHP) are the most commonly used MCDM methods, which combine subjective and personal preferences in risk assessment process. However, AHP involves human subjectivity, which introduces vagueness type of uncertainty and requires the usage of decision making under those uncertainties. In this paper it was considered to deal with uncertainty by using the fuzzy-based techniques. However, nowadays there exist multiple Fuzzy AHP methodologies developed by different authors. In this paper, these Fuzzy AHP methodologies will be compared, and the most appropriate Fuzzy AHP methodology for the application in case of environmental risks assessment will be offered on the basis of this comparison.

scholarly journals Canada’s Environmental Farm Plan: Evaluating Implementation, Use of Services, and the Influence of Social Factors

2020 ◽  
Vol 9 (4) ◽  
pp. 1
Author(s):  
Paul Smith ◽  
Carrie Bibik ◽  
Jon Lazarus ◽  
David Armitage ◽  
Cindy Bradley-Macmillan ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Social Factors ◽  
Financial Incentives ◽  
Assessment Tool ◽  
Environmental Risks ◽  
Service Needs ◽  
Action Plans ◽  
Related Services ◽  
Factors Influencing ◽  
Use Of Services

Canada’s Environmental Farm Plan (EFP) is a voluntary, self-administered education and risk assessment tool that assists farmers in developing customized action plans to address environmental risks on their farms. During 2010-11 a study was undertaken in Ontario to evaluate the level of implementation of the EFP, the use of related services and resources, and social factors influencing implementation and services used. A confidential survey of 189 Ontario farmers with EFPs revealed high levels of implementation and significant investments of time and money to reduce environmental risks and improve environmental conditions. Farmers completed or were implementing 67.5% (median) of their action plans, up from 55% reported in a survey in 1999. Farmers invested an average of C$69,600 per farm in agri-environmental activities (of which 73% was drawn from their own funds) and spent 130 hours of their time per farm. Percent implemented, time and cost are all much higher compared to the survey in 1999. Farmers used many existing services in preparing and implementing their EFPs. In 2010, social factors significantly influenced motivation, preferences and service needs including education, age and main commodity produced. Also in 2010, 95% percent of farmers reported perceived environmental improvements on their farm operations. The results emphasize the importance of combining risk assessment, education and financial incentives as well as offering a range of program services to appeal to the varied needs of different farmers.

BrHgO• + C2H4 and BrHgO• + HCHO in Atmospheric Oxidation of Mercury: Determining Rate Constants of Reactions with Pre-Reactive Complexes and a Bifurcation

2019 ◽  
Author(s):  
Khoa T. Lam ◽  
Curtis J. Wilhelmsen ◽  
Theodore Dibble
Keyword(s):  
Hydrogen Atom ◽  
Quantum Chemistry ◽  
Transition State ◽  
Rate Constant ◽  
Rate Constants ◽  
Minimum Energy ◽  
Atmospheric Oxidation ◽  
Minimum Energy Path ◽  
Oh Radical ◽  
Hydrogen Atoms

Models suggest BrHgONO to be the major Hg(II) species formed in the global oxidation of Hg(0), and BrHgONO undergoes rapid photolysis to produce the thermally stable radical BrHgO•. We previously used quantum chemistry to demonstrate that BrHgO• can, like OH radical, readily can abstract hydrogen atoms from sp<sup>3</sup>-hybridized carbon atoms as well as add to NO and NO<sub>2</sub>. In the present work, we reveal that BrHgO• can also add to C<sub>2</sub>H<sub>4</sub> to form BrHgOCH<sub>2</sub>CH<sub>2</sub>•, although this addition appears to proceed with a lower rate constant than the analogous addition of •OH to C<sub>2</sub>H<sub>4</sub>. Additionally, BrHgO• can readily react with HCHO in two different ways: either by addition to the carbon or by abstraction of a hydrogen atom. The minimum energy path for the BrHgO• + HCHO reaction bifurcates, forming two pre-reactive complexes, each of which passes over a separate transition state to form a different product.

Petroleum Industry Environmental Performance and Risk

2014 ◽  
pp. 358-387
Author(s):  
Lidia Hrncevic
Keyword(s):  
Risk Assessment ◽  
Environmental Impact ◽  
Risk Analysis ◽  
Environmental Risk ◽  
Potential Risk ◽  
Environmental Risk Assessment ◽  
Petroleum Industry ◽  
Environmental Risks ◽  
Pollution Sources ◽  
Waste Generation

The petroleum industry holds long- and short-term environmental risks. Besides production fluids, all petroleum industry activities involve either use of fluids, which contain abundant substances, or waste generation, both associated with potential risk to the environment. The principal environmental risk associated with the petroleum industry is the risk of fluid spill/emission to the environment. Although in recent decades the risk analysis methodologies have matured, to date there is still no universally accepted methodology for environmental risk assessment in petroleum industry. In this chapter, the petroleum industry’s environmental incident history and statistics are presented. The environmental impact of the petroleum industry’s activities, its extent, and trends are analyzed. The overview of pollution sources with associated environmental risk is given along with the analysis of the causes and consequences of incidents in the petroleum industry.

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