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Environmental consequences of electricity generation are often determined using average emission factors. However, as different interventions are incrementally pursued in electricity systems, the resulting marginal change in emissions may differ from what one would predict based on system-average conditions. Here, we estimate average emission factors and marginal emission factors for CO2, SO2 , and NOx from fossil and nonfossil generators in the Midcontinent Independent System Operator (MISO) region during years 2007-2016. We analyze multiple spatial scales (all MISO; each of the 11 MISO states; each utility; each generator) and use MISO data to characterize differences between the two emission factors (average; marginal). We also explore temporal trends in emissions factors by hour, day, month, and year, as well as the differences that arise from including only fossil generators versus total generation. We find, for example, that marginal emission factors are generally higher during late-night and early morning compared to afternoons. Overall, in MISO, average emission factors are generally higher than marginal estimates (typical difference: ~20%). This means that the true environmental benefit of an energy efficiency program may be ~20% smaller than anticipated if one were to use average emissions factors. Our analysis can usefully be extended to other regions to support effective near-term technical, policy and investment decisions based on marginal rather than only average emission factors. [ABSTRACT FROM AUTHOR]

DecaBDE has been widely used as flame retardant in electrical and electronic equipment (EEE). It has recently been listed in Annex A of the Stockholm Convention. The time series flow, stock, and emission of DecaBDE in EEE in Japan were quantified. On this basis, a risk/risk trade-off analysis of substituting DecaBDE with triphenyl phosphate (TPhP) that is one possible phosphorus-based alternative was conducted. The stock of DecaBDE reached a maximum of ~42 000 t in 1995. Even though the demand flow was negligible in 2030, the stock was modeled to be still ~470 t. The outflow of DecaBDE, from the use phase to the disposal phase, peaked at ~4500 t/yr. in 2001. The DecaBDE emission to atmosphere was mainly derived from the production phase before 1990. The use phase became the largest contributor to the total emission from 1995 to 2000. Whereas the disposal phase dominated the total emission from 2000 onward. In the substitution analysis, a trade-off between human and ecological health effect was revealed in case of replacing DecaBDE with TPhP. This study attempted to give an overall picture of DecaBDE application at national level providing insights into relevant environmental policy making. [ABSTRACT FROM AUTHOR]

The benefits and impacts of unconventional natural gas development are realized at different spatial scales, calling into question the appropriate jurisdictional level at which to set and enforce environmental policy. This paper evaluates impact fee allocation under Pennsylvania Act 13, which authorizes Commonwealth payments to Pennsylvania counties to offset damages from unconventional natural gas extraction in exchange for consolidated state-level regulatory authority. We evaluate the adequacy of damage compensation allocation for impacts that are spatially and temporally removed from the well site, using the air emissions associated with natural gas wastewater transport as a case study. Wastewater transport from wells eligible for 2011 impact fee disbursement calculations generated an estimated $11.6 million in air emission damages from 2004 to 2013, with 35% of damages occurring out-of-state and an average of 94% of damages occurring out-of-county. We find that compensatory payments from Pennsylvania Act 13, which are based upon the number of wells drilled in a county in a single year, inadequately account for spatially and temporally distributed impacts from wastewater transport. This case study of Pennsylvania Act 13 highlights potential issues associated with central regulators using compensatory payments as a means of resolving jurisdictional conflict. In cases where the central regulator benefits from the polluting activity, we argue that there is incentive to focus compensation on local damages and undervalue regional and spatially distributed damages in compensation algorithms. [ABSTRACT FROM AUTHOR]

We develop a multicriteria decision-making model coupled with scenario analysis to quantitatively elucidate the reciprocal effect between a mandatory pollutant emissions reduction policy and industrial structure change within the manufacturing sector on the basis of an in-depth study of a well-developed coastal area in East China, Ningbo City, toward 2020. First, 18 two-digit level industries (TDLIs) in the manufacturing sector are screened out due to intensive emissions of the four pollutants (COD, NH3-N, SO2, and NOx). Second, a model is established to identify the optimal solution for the industrial structure adjustment of the 18 TDLIs under two scenarios, the "business-as-usual" scenario and the "industrial structure adjustment" scenario. Both scenarios are expanded into three subscenarios. Quantitative constraint conditions and two criteria are formulated to screen out the optimal solutions. We propose a coefficient of industrial structure adjustment, Ki, which could clearly reflect the policy preference in terms of industrial development and reallocate the quota of the four-pollutant emission among the 18 TDLIs with regards to the different expectations of economy development in 2020. The model will help local authorities make tailored policies to reduce pollution emissions effectively through industrial structure change by delicately allocating the pollutant emission quota and setting reasonable targets of emission intensity reduction among TDLIs. [ABSTRACT FROM AUTHOR]

Emission-control policies have been implemented in Europe and North America since the 1990s for polychlorodibenzodioxins (PCDDs) and furans (PCDFs). To assess the effect of these policies on temporal trends and spatial patterns for these compounds in a large European river system, sediment cores were collected in seven depositional areas along the Rhone River in France, dated, and analyzed for PCDDs and PCDFs. Results show concentrations increase in the downstream direction and have decreased temporally at all sites during the last two decades, with an average decrease of 83% from 1992 to 2010. The time for a 50% decrease in concentrations (t1/2) averaged 6.9 ± 2.6 and 9.1 ± 2.9 years for the sum of measured PCDDs and PCDFs, respectively. Congener patterns are similar among cores and indicate dominance of regional atmospheric deposition and possibly weathered local sources. Local sources are clearly indicated at the most downstream site, where concentrations of the most toxic dioxin, TCDD, are about 2 orders of magnitude higher than at the other six sites. The relatively steep downward trends attest to the effects of the dioxin emissions reduction policy in Europe and suggest that risks posed to aquatic life in the Rhone River basin from dioxins and furans have been greatly reduced. [ABSTRACT FROM AUTHOR]

This paper explores whether a Panama Canal Authority pollution tax could be an effective economic instrument to achieve Emission Control Area (ECA)-like reductions in emissions from ships transiting the Panama Canal. This tariff-based policy action, whereby vessels in compliance with International Maritime Organisation (IMO) ECA standards pay a lower transit tariff than noncompliant vessels, could be a feasible alternative to petitioning for a Panamanian ECA through the IMO. A $4.06/container fuel tax could incentivize ECA-compliant emissions reductions for nearly two-thirds of Panama Canal container vessels, mainly through fuel switching; if the vessel(s) also operate in IMO-defined ECAs, exhaust-gas treatment technologies may be cost-effective. The RATES model presented here compares current abatement technologies based on hours of operation within an ECA, computing costs for a container vessel to comply with ECA standards in addition to computing the Canal tax that would reduce emissions in Panama. Retrofitted open-loop scrubbers are cost-effective only for vessels operating within an ECA for more than 4500 h annually. Fuel switching is the least-cost option to industry for vessels that operate mostly outside of ECA regions, whereas vessels operating entirely within an ECA region could reduce compliance cost with exhaust-gas treatment technology (scrubbers). [ABSTRACT FROM AUTHOR]

Lifecycle analysis (LCA) metrics of greenhouse gas emissions are increasingly being used to select technologies supported by climate policy. However, LCAs typically evaluate the emissions associated with a technology or product, not the impacts of policies. Here, we show that policies supporting the same technology can lead to dramatically different emissions impacts per unit of technology added, due to multimarket responses to the policy. Using a policy-based consequential LCA, we find that the lifecycle emissions impacts of four US biofuel policies range from a reduction of 16.1 gCO2e to an increase of 24.0 gCO2e per MJ com ethanol added by the policy. The differences between these results and representative technology-based LCA measures, which do not account for the policy instrument driving the expansion in the technology, illustrate the need for policy-based LCA measures when informing policy decision making. [ABSTRACT FROM AUTHOR]

We investigate empirically how national-level CO2 emissions are affected by urbanization and environmental policy. We use statistical modeling to explore panel data on annual CO2 emissions from 80 countries for the period 1983-2005. Random- and fixed-effects models indicate that, on the global average, the urbanization-emission elasticity value is 0.95 (i.e., a 1 % increase in urbanization correlates with a 0.95% increase in emissions). Several regions display a statistically significant, positive elasticity for fixed- and random-effects models: lower-income Europe, India and the Sub-Continent, Latin America, and Africa. Using two proxies for environmental policy/outcomes (ratification status for the Kyoto Protocol: the Yale Environmental Performance Index), we find that in countries with stronger environmental policy/outcomes, urbanization has a more beneficial (or, a less negative) impact on emissions. Specifically, elasticity values are -1.1 (0.2.1) for higher-income (lower-income) countries with strong environmental policy, versus 0.65 (13) for higher-income (lower-in come) countries with weak environmental policies. Our rinding that the urbanization-emissions elasticity may depend on the strength of a country's environmental policy, not just marginal increases in income, is in contrast to the idea of universal urban scaling laws that can ignore local context. Most global population growth in the coming decades is expected to occur in urban areas of lower-income countries, which underscores the importance of these findings. [ABSTRACT FROM AUTHOR]

For obtaining type approval in the European Union, light-duty vehicles have to comply with emission limits during standardized laboratory emissions testing. Although emission limits have become more stringent in past decades, light-duty vehicles remain an important source of nitrogen oxides and carbon monoxide emissions in Europe. Furthermore, persisting air quality problems in many urban areas suggest that laboratory emissions testing may not accurately capture the on-road emissions of light-duty vehicles. To address this issue, we conduct the first comprehensive on-road emissions test of light-duty vehicles with state-of-the-art Portable Emission Measurement Systems. We find that nitrogen oxides emissions of gasoline vehicles as well as carbon monoxide and total hydrocarbon emissions of both diesel and gasoline vehicles generally remain below the respective emission limits. By contrast, nitrogen oxides emissions of diesel vehicles (0.93 ± 0.39 grams per kilometer [g/km]), including modern Euro 5 diesel vehicles (0.62 ± 0.19 g/km), exceed emission limits by 320 ± 90%. On-road carbon dioxide emissions surpass laboratory emission levels by 21 ± 9%, suggesting that the current laboratory emissions testing fails to accurately capture the on-road emissions of light-duty vehicles. Our findings provide the empirical foundation for the European Commission to establish a complementary emissions test procedure for light-duty vehicles. This procedure could be implemented together with more stringent Euro 6 emission limits in 2014. The envisaged measures should improve urban air quality and provide incentive for innovation in the automotive industry. [ABSTRACT FROM AUTHOR]

Beijing, the capital of China, has experienced rapid motorization since 1990; a trend that is likely to continue. The growth in vehicles and the corresponding emissions create challenges to improving the urban air quality. In an effort to reduce the impact of vehicle emissions on urban air quality, Beijing has adopted a number of vehicle emission control strategies and policies since the mid 1990s. These are classified into seven categories: (1) emission control on new vehicles; (2) emission control on in-use vehicles; (3) fuel quality improvements; (4) alternative-fuel and advanced vehicles; (5) economic policies; (6) public transport; and (7) temporal traffic control measures. Many have proven to be successful, such as the Euro emission standards, unleaded gasoline and low sulfur fuel, temporal traffic control measures during the Beijing Olympic Games, etc. Some, however, have been failures, such as the gasoline-to-LPG taxi retrofit program. Thanks to the emission standards for new vehicles as well as other controls, the fleet-average emission rates of CO, HC, NOX, and PM10 by each major vehicle category are decreasing over time. For example, gasoline cars decreased fleet-average emission factors by 12.5% for CO, 10.0% for HC, 5.8% for NOX, and 13.0% for PM10 annually since 1995, and such a trend is likely to continue. Total emissions for Beijing's vehicle fleet increased from 1995 to 1998. However, they show a clear and steady decrease between 1999 and 2009. In 2009, total emissions of CO, HC, NOX, and PM10 were 845000 t, 121000 t, 84000 t, and 3700 t, respectively; with reductions of 47%, 49%, 47%, and 42%, relative to 1998. Beijing has been considered a pioneer in controlling vehicle emissions within China, similar to the role of California to the U.S. The continued rapid growth of vehicles, however, is challenging Beijing's policy-makers. [ABSTRACT FROM AUTHOR]

The flow of pollution through international trade flows has the ability to undermine environmental policies, particularly for global pollutants. In this article we determine the CO2 emissions embodied in international trade among 87 countries for the year 2001. We find that globally there are over 5.3 Gt of CO2 embodied in trade and that Annex B countries are net importers of CO2 emissions. Depending on country characteristics—such as size variables and geographic location—there are considerable variations in the embodied emissions. We argue that emissions (embodied in trade may have a significant impact on participation in and effectiveness of global climate policies such as the Kyoto Protocol. We discuss several policy options to reduce the impact of trade in global climate policy. If countries take binding commitments as a part of a coalition, instead of as individual countries, then the impacts of trade can be substantially reduced. Adjusting emission inventories for trade gives a more consistent description of a country's environmental pressures and circumvents many trade related issues'. It also gives opportunities to exploit trade as a means of mitigating emissions. Not least, a better understanding of the role that trade plays in a country's economic and environmental development will help design more effective and participatory climate policy post-Kyoto. [ABSTRACT FROM AUTHOR]

The Clean Air Act establishes New Source Review (NSR) programs that apply to construction or modification of major stationary sources. In 2002 and 2003, EPA revised its rules to narrow NSR's coverage of renovations. Congress mandated a National Research Council study of the revisions' impacts. In that study, we used an electricity-sector model to explore possible effects of the equipment replacement provision (ERP), the principal NSR change directed at power plants. We find that, assuming implementation of the Clean Air Interstate Rule (CAIR), tight enforcement of the prerevision NSR rules would likely lead to no or limited decreases in national emissions compared to policies such as ERP. However, emissions might shift forward in time because the previous NSR rules would depress allowance prices, discouraging banking and encouraging allowance use. Only under the most aggressive prerevision NSR enforcement scenario, in which essentially all coal capacity is compelled to retrofit controls by 2020, do NOx emissions fall below ERP levels. Even then, total 2007-2020 SO2 emissions are unaffected. Further decreases in national emissions could be accomplished more cheaply by tighter emissions caps than through NSR because caps provide incentives for efficient operating strategies, such as fuel switching, as well as retrofits. [ABSTRACT FROM AUTHOR]

Low-cost, practicable techniques are required to limit the release of volatile organic compound-containing fumigants such as 1,3-D to the atmosphere. In this study, we aimed to quantify 1,3-D diffusion and emission from laboratory soil columns maintained under realistic conditions and thereby assess the efficacy of soil irrigation as a technique for reducing emissions. In two soils (one relatively high, and one relatively low, in organic matter), irrigation led to a limiting of upward diffusion of the fumigant and to the maintenance of higher soil gas concentrations. Therefore, rather than being emitted from the column, the 1,3-D was maintained in the soil where it was ultimately degraded. As a consequence, emission of 1,3-D from the irrigated columns was around half of that from the nonirrigated columns. It is concluded that surface irrigation represents an effective, low-cost, and readily practicable approach to lessening the environmental impact of 1,3-D fumigant use. In addition, the higher organic matter soil exhibited emissions of around one-fifth of the lower organic matter soil in both irrigated and nonirrigated treatments, due to markedly enhanced degradation of the fumigant. Organic matter amendment of soils may, therefore, also represent an extremely effective, relatively low-cost approach to reducing 1,3-D emissions. [ABSTRACT FROM AUTHOR]

Passive air samplers (polyurethane foam disks) were deployed at 23 background locations along a broadly west-east transect in 8 northern European countries and analyzed for PCBs, PBDEs, PAHs, and a range of organochlorine pesticides (HCB, DDTs, and DDEs). PCBs and PAHs were highest at the center of the transect (Denmark) and lowest in northern Norway. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher DDE and DDT levels occurred in Eastern Europe and at several sites in Central Europe. PBDE levels were generally similar at all sites, but lower for some locations in Eastern Europe and Ireland. Emissions information for PCBs, HCB, and PBDEs was used as input for a multi-media chemical fate model, to generate predicted air concentrations and compare with these measured values. Different scenarios were highlighted by this exercise: (i) country and compound combinations where the national inventory gave predicted air concentrations in close agreement with those measured (e.g., PCBs in the UK); (E) country and compound combinations where predicted concentrations were well below those measured, but where advection of emissions from elsewhere is likely to be important (e.g., PCBs in Norway); (iii) consistent underestimation of compound concentrations by the emissions modeling (i.e., HCB); and (iv) general overestimation of ambient concentrations (i.e., PBDEs). Air mass trajectory analysis showed the likely role of long-range atmospheric transport (LRAT) on national levels. In general, advection from the south and west of Europe appeared to contribute to ambient POPs levels for countries in the center and northeast of the transect. Guidelines are presented as to how countries that want to assess their POPs source inventories can do so with this relatively cheap initial screening approach. [ABSTRACT FROM AUTHOR]

Worldwide people are exposed to toxic ultrafine particles (UFP, with diameters (dp) less than 100 nm) and nanoparticles (NP, dp < 50 nm) under a variety of circumstances. To date, very limited information is available on human exposure to freshly emitted UFP and NP while traveling on major roads and freeways. We report in-cabin and outdoor measurements of particle number concentration and size distributions while driving three vehicles on Los Angeles freeways. Particle number concentrations and size distributions were measured under different vehicle ventilation settings. When the circulation fan was set to on, with substantial external air intake, outside changes in particle counts caused corresponding in-cabin changes approximately 30–60 s later, indicating an maximal air exchange rate of about 120–60 h-1. Maximum in-cabin protection (∼85%) was obtained when both fan and recirculation were on. In-cabin and outdoor particle size distributions in the 7.9–217 nm range were observed to be mostly bimodal, with the primary peak occurring at 10–30 nm and the secondary at 50–70 nm. The vehicle's manufacture-installed particle filter offered an in-cabin protection of about 50% for particles in the 7–40 nm size range and 20–30% for particles in the 40 to ∼200 nm size range. For an hour daily commute exposure, the in-vehicle microenvironment contributes approximately 10–50% of people's daily exposure to UFP from traffic. [ABSTRACT FROM AUTHOR]

For more than 20 years the global emissions and the lifetime of methane have probably been constant, so the buildup of methane in the atmosphere has been slowing down for as long. During this time, there have been periodic events occurring every seven to eight years, when global methane concentrations increased by some 10 ppb and later fell back, in some cases due to temporary increases of emissions from the northern tropics that spread to the global scale. These conclusions are derived from the accumulated global observations that now span 23 years and define the role of human activities in the recent cycle of atmospheric methane. [ABSTRACT FROM AUTHOR]

Factors associated with sources, transport, and fate of volatile organic compounds (VOCs) in groundwater from aquifers throughout the United States were evaluated using statistical methods. Samples were collected from 1631 wells throughout the conterminous United States between 1996 and 2002 as part of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. Water samples from wells completed in aquifers used to supply drinking water were analyzed for more than 50 VOCs. Wells were primarily rural domestic water supplies (1184), followed by public water supplies (216); the remaining wells (231) supplied a variety of uses. The median well depth was 50 meters. Age-date information shows that about 60% of the samples had a fraction of water recharged after 1953. Chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene were some of the frequently detected VOCs. Concentrations generally were less than 1 μg/L. Source factors include, in order of importance, general land-use activity, septic/sewer density, and sites where large concentrations of VOCs are potentially released, such as leaking underground storage tanks. About 10% of all samples had V0C mixtures that were associated with concentrated sources; 20% were associated with dispersed sources. Important transport factors included well/screen depth, precipitation/groundwater recharge, air temperature, and various soil characteristics. Dissolved oxygen was strongly associated with VOCs and represents the fate of many VOCs in groundwater. Well type (domestic or public water supply) was also an important explanatory factor. Results of multiple analyses show the importance of (1) accounting for both dispersed and concentrated sources of VOCs, (2) measuring dissolved oxygen when sampling wells to help explain the fate of VOCs, and (3) limiting the type of wells sampled in monitoring networks to avoid unnecessary variance in the data, or controlling for this variance during data analysis. [ABSTRACT FROM AUTHOR]

Biomass combustion emissions make a significant contribution to the overall particulate pollution in the troposphere. Wildland or prescribed burns and residential wood combustion emissions can vary due to differences in fuel, season, time of day, and the nature of the combustion. Inadequate understanding of the relevance of these biomass combustion emissions is due to the lack of characterization of open combustion emissions and the limited understanding of the differences between these and residential wood combustion. To provide new insight to biomass combustion emissions, sampling was conducted in several types of conditions. Semi-volatile organic compounds (SVOC) were collected during four separate prescribed burns in three different ecosystems, Mariposa Sequoia Grove within Yosemite National Park, CA, desert brushes of central rural Nevada, and Toiyabye National Forest near Lake Tahoe, NV. SVOC samples were also collected under controlled conditions for several wildland fuels, including conifer needles, wildland grasses, and sagebrush. Fireplace emissions from simulated residential wood combustion were also collected and are included here for comparison. A high degree of variability was found in the emissions of organic carbon, elemental carbon, levoglucosan, methoxy phenols, and organic acids. The variability in the emissions of levoglucosan does not correlate with the PM2.5 gravimetric mass and thus may affect source apportionment estimates. [ABSTRACT FROM AUTHOR]

As part of the State Implementation Plan for attaining the National Ambient Air Quality Standard for ozone, the Texas Commission of Environmental Quality has created a Highly Reactive Volatile Organic Compounds (HRVOC) Emissions Cap and Trade Program for industrial point sources in the Houston/Galveston/Brazoria area. This series of papers examines the potential air quality impacts of this new emission trading program through photochemical modeling of potential trading scenarios; this paper examines the air quality impact of allowing facilities to trade chlorine emission reductions for HRVOC allocations on a reactivity weighted basis. The simulations indicate that trading of anthropogenic chlorine emission reductions for HRVOC allowances at a single facility or between facilities, in general, resulted in improvements in air quality. Decreases in peak 1-h averaged and 8-h averaged ozone concentrations associated with trading chlorine emissions for HRVOC allocations on a Maximum Incremental Reactivity (MIR) basis were up to 0.74 ppb (0.63%) and 0.56 ppb (0.61%), respectively. Air quality metrics based on population exposure decreased by up to 3.3% and 4.1% for 1-h and 8-h averaged concentrations. These changes are small compared to the maximum changes in ozone concentrations due to the VOC emissions from these sources (5–10 ppb for 8-h averages; up to 30 ppb for 1-h averages) and the chlorine emissions from the sources (5–10 ppb for maximum concentrations over wide areas and up to 70 ppb in localized areas). The simulations indicate that the inclusion of chlorine emissions in the trading program is likely to be beneficial to air quality and is unlikely to cause localized increases in ozone concentrations (‘hot spots’). [ABSTRACT FROM AUTHOR]

The article reflects on the European Union Emissions Trading Scheme (ETS). The scheme, commenced on January 1, 2005, aims to regulate emissions of carbon dioxide, which was divided into two phases. The first phase plans to prepare the European Union's economy for its obligations under the Kyoto Protocol from 2005 to 2007, while the second phase will run from 2008 to 2012. The European Unions's ETS covers 11,000 to 12,000 installations from 5,000 companies from different sectors throughout Europe.

The article provides an overview of the mercury control technologies aimed at lessening the mercury emissions from coal-fired electric utility boilers in the U.S. The author stressed that mercury emissions from anthropogenic emission sources posed a global threat that needs to be subsided. In response, the U.S. Environmental Protection Agency proclaimed the Clean Air Mercury Rule to permanently cap and abridge emissions of mercury from coal-fired power plants. Another regulation promulgated is the Clean Air Interstate Rule, which compels further reduction of sulphur dioxide and nitrogen oxides from these power plants. Among the control technologies stressed include flue-gas desulfurization and limestone forced- oxidation.

This article reports that as the result of testing the air emissions from more than 30,000 indoor office furnishings and products-including many office cubicles-over 30 years, Marilyn Black, a scientist, attests that most newer office furniture and equipment produce much fewer potentially toxic emissions than their predecessors. A typical cubicle has at least a dozen components, including coatings, varnishes, fiberglass, textiles, fabrics, adhesives, and finishes. By making the first measurements of the emissions coming from cubicles in the mid-1980s, it was revealed that some of those components were sources of toxic compounds. That was an incentive for action, especially given that some of Black first cubicle tests were conducted as part of a legal settlement. Employees had alleged that the cubicles inside U.S. Environmental Protection Agency buildings-including the water side Mall headquarters in emitting off of furniture, carpeting, and wall coverings were pretty much staying in the building and being recirculated.

The article reports on the impact of the 1987 Montreal Protocol on climate change because it has protected the ozone layer by controlling emissions of chlorofluorocarbons (CFC) and other related chemicals on a global scale. The treaty also seems to have slowed down climate change. It also prevented some global warming by cutting back on ozone-depleting substances such as CFC which are also potent greenhouse gases. According to an article published in "Proceedings of the National Academy of Sciences U.S.A.," the treaty had more impact on climate change than the the first phase of targets set by the Kyoto Protocol, which limits carbon dioxide and other greenhouse gases.

The article cites key findings from a study conducted by the Environmental Protection Agency (EPA) showing that greenhouse gas (GHG) emissions, specifically carbon dioxide, have continued to increase in the United States from 1990 to 2004. The EPA notes that carbon dioxide accounts for most of the GHG emissions and that industries, transportation and energy producers are the biggest sources of GHG emissions. Concerns are raised that the United States will not meet its target to reduce GHG emissions by 18% by 2012.

This article focuses on international approval for carbon dioxide emissions. In July, the European Commission (EC) approved eight countries' national allocation plans, which set out how they intend to distribute carbon dioxide emissions allowances to energy intensive industrial plants. The EC's decision clears the way for more than 5000 facilities out of an estimated 12,000 in the 25 member states-to participate in the scheme. The approved plans were from Denmark, Ireland, The Netherlands, Slovenia, and Sweden, outlines from Austria, Germany, and the United Kingdom were affirmed on condition that some technical changes are made.