The authors examine the impact that oxygenated volatile organic compounds have on air quality and climate. Topics discussed include ozonolysis of halides at the Sea surface and halogenation of ...dissolved organic matter (DOM) by radical and nonradical RHS.
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Human activity has led to increased atmospheric concentrations of many gases, including halocarbons, and may lead to emissions of many more gases. Many of these gases are, on a per molecule basis, ...powerful greenhouse gases, although at present‐day concentrations their climate effect is in the so‐called weak limit (i.e., their effect scales linearly with concentration). We published a comprehensive review of the radiative efficiencies (RE) and global warming potentials (GWP) for around 200 such compounds in 2013 (Hodnebrog et al., 2013, https://doi.org/10.1002/rog.20013). Here we present updated RE and GWP values for compounds where experimental infrared absorption spectra are available. Updated numbers are based on a revised “Pinnock curve”, which gives RE as a function of wave number, and now also accounts for stratospheric temperature adjustment (Shine & Myhre, 2020, https://doi.org/10.1029/2019MS001951). Further updates include the implementation of around 500 absorption spectra additional to those in the 2013 review and new atmospheric lifetimes from the literature (mainly from WMO (2019)). In total, values for 60 of the compounds previously assessed are based on additional absorption spectra, and 42 compounds have REs which differ by >10% from our previous assessment. New RE calculations are presented for more than 400 compounds in addition to the previously assessed compounds, and GWP calculations are presented for a total of around 250 compounds. Present‐day radiative forcing due to halocarbons and other weak absorbers is 0.38 0.33–0.43 W m−2, compared to 0.36 0.32–0.40 W m−2 in IPCC AR5 (Myhre et al., 2013, https://doi.org/10.1017/CBO9781107415324.018), which is about 18% of the current CO2 forcing.
Plain Language Summary
Human activity has led to increased atmospheric concentrations of many gases, including halocarbons (used, e.g., in refrigeration and air conditioning), and may lead to emissions of many other gases. While some halocarbons, such as chlorofluorocarbons (CFCs), are known to deplete stratospheric ozone, they are also powerful greenhouse gases contributing to radiative forcing (the net change in the energy balance of the Earth system) and hence climate change. We find that the present‐day contribution from halocarbons and related compounds to radiative forcing is about 18% of the forcing due to increased concentrations of CO2. By using established methods and available laboratory measurements of absorption of infrared radiation for each gas, we quantify the radiative efficiency (i.e., a compound's strength as a greenhouse gas) for a total of around 600 compounds. For around 250 compounds we provide so‐called global warming potentials (GWP), which are used to compare the climate impact of emissions of different gases and are commonly used to inform policy decisions. Results presented here can be used to derive values for emission metrics other than GWP. The present work is the most comprehensive review of the radiative efficiency and GWP of halocarbons and other weak absorbers performed to date.
Key Points
Radiative efficiencies are reassessed for more than 600 compounds and global warming potentials calculated for around 250 of these
Forty‐two compounds have >10% different radiative efficiency compared to a comprehensive review in 2013
Present‐day radiative forcing due to halocarbons and other weak absorbers is 0.38 0.33–0.43 W m−2, which is ~18% of the CO2 forcing
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In the mid‐1970s, it was recognized that chlorofluorocarbons (CFCs) were strong greenhouse gases that could have substantial impacts on radiative forcing of climate change, as well as being ...substances that deplete stratospheric ozone. Around a decade later, this group of radiatively active compounds was expanded to include a large number of replacements for ozone‐depleting substances such as chlorocarbons, hydrochlorocarbons, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), bromofluorocarbons, and bromochlorofluorocarbons. This paper systematically reviews the published literature concerning the radiative efficiencies (REs) of CFCs, bromofluorocarbons and bromochlorofluorocarbons (halons), HCFCs, HFCs, PFCs, sulfur hexafluoride, nitrogen trifluoride, and related halogen containing compounds. In addition, we provide a comprehensive and self‐consistent set of new calculations of REs and global warming potentials (GWPs) for these compounds, mostly employing atmospheric lifetimes taken from the available literature. We also present global temperature change potentials for selected gases. Infrared absorption spectra used in the RE calculations were taken from databases and individual studies and from experimental and ab initio computational studies. Evaluations of REs and GWPs are presented for more than 200 compounds. Our calculations yield REs significantly (> 5%) different from those in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) for 49 compounds. We present new RE values for more than 100 gases which were not included in AR4. A widely used simple method to calculate REs and GWPs from absorption spectra and atmospheric lifetimes is assessed and updated. This is the most comprehensive review of the radiative efficiencies and global warming potentials of halogenated compounds performed to date.
Key Points
We review REs of CFCs,Bromocarbons and halons, HCFCs,HFCs,PFCs, SF6,NF3.
We present calculations of REs and GWPs for these compounds.
We present Global Temperature change Potentials (GTPs) for selected gases.
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Inhalation anaesthetics and climate change Sulbaek Andersen, M. P.; Sander, S. P.; Nielsen, O. J. ...
British journal of anaesthesia : BJA,
12/2010, Volume:
105, Issue:
6
Journal Article
Peer reviewed
Open access
Background Although the increasing abundance of CO2 in our atmosphere is the main driver of the observed climate change, it is the cumulative effect of all forcing agents that dictate the direction ...and magnitude of the change, and many smaller contributors are also at play. Isoflurane, desflurane, and sevoflurane are widely used inhalation anaesthetics. Emissions of these compounds contribute to radiative forcing of climate change. To quantitatively assess the impact of the anaesthetics on the forcing of climate, detailed information on their properties of heat (infrared, IR) absorption and atmospheric lifetimes are required. Methods We have measured the IR spectra of these anaesthetics and conducted calculations of their contribution to radiative forcing of climate change recognizing the important fact that radiative forcing is strongly dependent on the wavelength of the absorption features. Results Radiative efficiencies of 0.453, 0.469, and 0.351 W m−2 ppb−1 and global warming potentials (GWPs) of 510, 1620, and 210 (100 yr time horizon) were established for isoflurane, desflurane, and sevoflurane, respectively. Conclusions On the basis of the derived 100 yr GWPs, the average climate impact per anaesthetic procedure at the University of Michigan is the same as the emission of ∼22 kg CO2. We estimate that the global emissions of inhalation anaesthetics have a climate impact which is comparable with that from the CO2 emissions from one coal-fired power plant or 1 million passenger cars.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Direct emissions of N2O from global transportation (land, air, water) are estimated to be 0.142 ± 0.065 Tg N2O–N yr−1 in 2010 with the majority (≈55%) of emissions resulting as an unwanted by-product ...from catalytic emission control systems of light-duty vehicles. Emissions from global transportation accounted for 3 ± 1% of current estimates of the total anthropogenic emissions. With anticipated improvements in the emission control systems of light-duty vehicles, the emissions of N2O from global transportation are expected to decline to 0.108 ± 0.065 Tg N2O–N yr−1 by 2030 despite a substantial increase in global transportation activity.
•Direct emissions of N2O from global transportation (land, air, water) are estimated to be 0.142 ± 0.065 Tg N2O–N yr−1 in 2010.•N2O emissions from global transportation accounted for 3 ± 1% of current estimates of the total anthropogenic emissions.•Emissions of N2O from global transportation are expected to decline to 0.108 ± 0.065 Tg N2O–N yr−1 by 2030.
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Commercial transportation fuels are complex mixtures containing hundreds or thousands of chemical components, whose composition has evolved considerably during the past 100 years. In conjunction with ...concurrent engine advancements, automotive fuel composition has been fine-tuned to balance efficiency and power demands while minimizing emissions. Pollutant emissions from internal combustion engines (ICE), which arise from non-ideal combustion, have been dramatically reduced in the past four decades. Emissions depend both on the engine operating parameters (e.g. engine temperature, speed, load, A/F ratio, and spark timing) and the fuel. These emissions result from complex processes involving interactions between the fuel and engine parameters. Vehicle emissions are comprised of volatile organic compounds (VOCs), CO, nitrogen oxides (NO(x)), and particulate matter (PM). VOCs and NO(x) form photochemical smog in urban atmospheres, and CO and PM may have adverse health impacts. Engine hardware and operating conditions, after-treatment catalysts, and fuel composition all affect the amount and composition of emissions leaving the vehicle tailpipe. While engine and after-treatment effects are generally larger than fuel effects, engine and after-treatment hardware can require specific fuel properties. Consequently, the best prospects for achieving the highest efficiency and lowest emissions lie with optimizing the entire fuel-engine-after-treatment system. This review provides a chemical perspective on the production, combustion, and environmental aspects of automotive fuels. We hope this review will be of interest to workers in the fields of chemical kinetics, fluid dynamics of reacting flows, atmospheric chemistry, automotive catalysts, fuel science, and governmental regulations.
This article, the sixth in the ACP journal series, presents data evaluated by the IUPAC Task Group on Atmospheric Chemical Kinetic Data Evaluation. It covers the heterogeneous processes involving ...liquid particles present in the atmosphere with an emphasis on those relevant for the upper troposphere/lower stratosphere and the marine boundary layer, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website since 2009. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. The experimental data on which the recommendations are based are provided in data sheets in separate appendices for the four surfaces considered: liquid water, deliquesced halide salts, other aqueous electrolytes and sulfuric acid.
Calculations using a three-dimensional global atmospheric chemistry model (IMPACT) indicate that n-C8F17CH2CH2OH (widely used in industrial and consumer products) degrades in the atmosphere to give ...perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs). PFOA is persistent, bioaccumulative, and potentially toxic. Molar yields of PFOA depend on location and season, are in the range of 1−10%, and are of the correct order of magnitude to explain the observed levels in Arctic fauna. Fluorotelomer alcohols such as n-C8F17CH2CH2OH appear to be a significant global source of persistent bioaccumulative perfluorocarboxylic acid pollution. This is the first modeling study of the atmospheric chemistry of a fluorotelomer alcohol.
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We argue that there is a need for a more precise of PFAS in a way that avoids including compounds with single CF
3
-, -CF
2
-, or &z.dbdsl;CF- groups and excludes TFA and compounds that degrade to ...just give TFA. An example that meets this need is the definition by the U.S. Environmental Protection Agency of PFAS as "per- and polyfluorinated substances that structurally contain the unit R-(CF
2
)-C(F)(R
1
)R
2
. Both the CF
2
and CF moieties are saturated carbons and none of the R groups (R, R
1
, or R
2
) can be hydrogen". Adoption of this definition, or one like it, would place future technical and regulatory discussions of the environmental impacts of organo-fluorine compounds on a sounder technical footing by focusing PFAS discussions and regulation on long-chain perfluoroalkyl sulfonic acids and perfluoroalkyl carboxylic acids.
Many existing definitions of PFAS are overly broad, there is a strong case for a more precise definition of regulated PFAS.
•Commercially relevant short-chain haloolefins will be released into the atmosphere.•Haloolefins have short atmospheric lifetimes (a few days or weeks).•Short-chain haloolefins degrade in the ...atmosphere giving HF, HCl, CO2 and CF3C(O)OH.•The degradation products do not pose a significant risk to ecosystems.
Short-chain haloolefins are being introduced as replacements for saturated halocarbons. The unifying chemical feature of haloolefins is the presence of a CC double bond which causes the atmospheric lifetimes to be significantly shorter than for the analogous saturated compounds. We discuss the atmospheric lifetimes, photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs) of haloolefins. The commercially relevant short-chain haloolefins CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) have short atmospheric lifetimes (days to weeks), negligible POCPs, negligible GWPs, and ODPs which do not differ materially from zero. In the concentrations expected in the environment their atmospheric degradation products will have a negligible impact on ecosystems. CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) are environmentally acceptable.
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