Mutagenic and carcinogenic potency of extracts of diesel and related environmental emissions: Summary and discussion of the results

The proposed conversion from gasoline powered automobiles to diesel powered vehicels has prompted the Environmental Protection Agency to evaluate the potential health effects associated with exposure to diesel emissions. At present, there is no direct epidemiological link between this exposure and human health. Therefore, a research program was constructed to compare the health effects associated with diesel emissions with those from other emission sources for which epidemiological information was available. The emission sources chosen were cigarette smoke, roofing tar, and coke oven. An additional comparative emission source which was a gasoline catalyst engine. Respirable particles from a variety of combustion sources have the potential of being carcinogenic and mutagenic. The objective of these studies was to determine the relative biological activity of the organic material adsorbed on these particles in both in vitro mutagenesis and in vitro and in vivo bioassays. The organic extracts from the following series of emission sources were quantitatively bioassayed in a matrix of tests for their carcinogenic and mutagenic activity: (1) a light-duty Oldsmobile diesel 350 engine; (2) a heavy-duty Caterpillar diesel engine; (3) a light-duty Nissan engine; (4) a Volkswagen Rabbit diesel engine; (5) cigarette smoke; (6) roofing tar; (7) coke oven; and (8) a gasoline catalyst Mustang. The test matrix consisted of the following bioassay: reverse mutation in Salmonella typhimurium; mitotic recombination in Saccharomyces cerevisiae; DNA damage in Syrian hamster embryo cells (SHE); sister chromatid exchange in CHO cells; gene mutation in L5178Y mouse lymphoma cells, Balb/c 3T3 mouse embryo fibroblasts and CHO cells; viral enhancement of SHE cells; oncogenic transformation in Balb/c 3T3 cells; and skin tumor initiation in SENCAR and C57 black mice. The results of this test matrix are discussed.     

The DNA damage activity (DDA) assay and its application to river waters and diesel exhausts

An extremely sensitive assay has been developed for DNA-damaging chemicals using a DNA repair-deficient strain of Escherichia coli. Considerable DNA-damaging activity has been demonstrated by this assay in natural surface-water samples and in diesel-exhaust particulate extracts.     

Mutagenic and carcinogenic potency of extracts of diesel and related environmental emissions: In vitro mutagenesis and oncogenic transformation

Extracts from emissions of four diesel engines, a gasoline engine and three related environmental samples were tested in four in vitro assay systems designed to detect carcinogenic or mutagenic activity of chemicals. Samples from three of four diesel extracts, the gasoline engine, and all three related samples were positive in an enhancement of viral transformation assay. Two diesel samples, the gasoline engine extract and extract from coke oven emissions were positive for mutation induction in Chinese hamster ovary cells. Only the gasoline engine extract and the coke oven sample were positive in a DNA fragmentation assay using alkaline sucrose gradients. Experiments using chemical transformation of Syrian hamster embryo cells as an assay method have not been completed.     

Mutagenic and carcinogenic potency of diesel and related environmental emissions: Salmonella bioassay

Due to the expected increase in the percentage of diesel vehicles in the United States, the Environmental Protection Agency must evaluate the health effects associated with exposure to diesel emissions. Respirable particles from a variety of combustion sources have the potential of being carcinogenic and mutagenic. The objective of these studies was to determine the relative biological activity of the organic material adsorbed on these particles in in vitro mutagenesis bioassays. The organic extracts from the following series of emission sources were bioassayed in the Salmonella assay for mutagenic activity: (1) a light-duty Oldsmobile diesel 350 engine; (2) a heavy-duty Caterpillar diesel engine; (3) a light-duty Nissan engine; (4) a Volkswagen Rabbit diesel engine; (5) cigarette smoke; (6) roofing tar; (7) coke oven; and (8) a gasoline catalyst Mustang. This paper provides a comparison of these sources within the Salmonella bioassay and also demonstrates how bacterial systems can be used as a quality assurance measure in in vivo testing.     

A new type of refrigerator and its cycle

The world is facing an energy and climate crisis. Globally, the energy sector emits 26 billion tonnes of CO₂ each year, and electricity production alone accounts for 41% of emissions (European Wind Energy Association. 2008. Pure Power: Wind Energy Scenarios up to 2030. European Wind Energy Association. p. 6). Currently, reducing CO₂ emissions and curbing climate change have become global priorities, and we only have a narrow window of time left in which to act. The new type of refrigerator can offer an immediate and concrete solution to the many energy and climate challenges that we are facing. This is an account of a new type of refrigerator and its cycle for use in the refrigeration industry. For its cycle, the working substance is air or other gases; its cycle is very similar to that of the reverse Brayton cycle (Hou, Y., Zhao, H. L., Chen, C. Z., and Xiong, L. Y. 2006. “Developments in Reverse Brayton Cycle Cryocooler in China.” Cryogenics 46 (5): 403–407). In the cycle of the new type of refrigerator, the isochoric exothermic process and the isothermal exothermic compression process replace the isobaric exothermic compression process of the reverse Brayton cycle. The new type of refrigerator can produce a net electrical energy, and it is not a perpetual motion machine, because the environmental enthalpy and atmospheric pressure can be utilized as the external energy sources, which cannot be performed by any other conventional refrigerators; therefore, the reliability and significance of this new type of refrigerator is self-evident.     

A quantitative integrated assessment of pollution prevention achieved by Integrated Pollution Prevention Control licensing

This paper presents an innovative, quantitative assessment of pollution avoidance attributable to environmental regulation enforced through integrated licensing, using Ireland's pharmaceutical-manufacturing sector as a case study. Emissions data reported by pharmaceutical installations were aggregated into a pollution trend using an Environmental Emissions Index (EEI) based on Lifecycle Assessment methodologies. Complete sectoral emissions data from 2001 to 2007 were extrapolated back to 1995, based on available data. Production volume data were used to derive a sectoral production index, and determine ‘no-improvement’ emission trends, whilst questionnaire responses from 20 industry representatives were used to quantify the contribution of integrated licensing to emission avoidance relative to these trends. Between 2001 and 2007, there was a 40% absolute reduction in direct pollution from 27 core installations, and 45% pollution avoidance relative to hypothetical ‘no-improvement’ pollution. It was estimated that environmental regulation avoided 20% of ‘no-improvement’ pollution, in addition to 25% avoidance under business-as-usual. For specific emissions, avoidance ranged from 14% and 30 kt a^− 1 for CO₂ to 88% and 598 t a^− 1 for SO_x. Between 1995 and 2007, there was a 59% absolute reduction in direct pollution, and 76% pollution avoidance. Pollution avoidance was dominated by reductions in emissions of VOCs, SO_x and NO_x to air, and emissions of heavy metals to water. Pollution avoidance of 35% was attributed to integrated licensing, ranging from between 8% and 2.9 t a^− 1 for phosphorus emissions to water to 49% and 3143 t a^− 1 for SO_x emissions to air. Environmental regulation enforced through integrated licensing has been the major driver of substantial pollution avoidance achieved by Ireland's pharmaceutical sector — through emission limit values associated with Best Available Techniques, emissions monitoring and reporting requirements, and performance targets specified in environmental management plans. This compliant sector offers a positive, but not necessarily typical, case study of IPPC effectiveness.     

Experimental investigation of diesel engine using EGR and fuelled with Karanja oil methyl ester

Karanja oil methyl ester (KOME), a biodiesel prepared from Karanja oil, a potential source of non-edible oil in India and a prospective alternative to the diesel fuel, shows comparable performance and considerable reduction in emissions except NO_x. Exhaust gas recirculation (EGR) is a popular method of reducing the NO_x emission. The aim of this experimental work was to study the potential of the cooled EGR in a direct injection compression ignition engine operating with the KOME and its blend. The study was conducted with the different EGR rates. Performance and emission parameters were compared by using diesel, KOME and its blend employing EGR and with the same fuels without EGR. The study also differentiates the effect of EGR on KOME and its blend with the neat diesel. The effect of EGR was found to be slightly higher for KOME biodiesel and its blend than for neat diesel. Increased NO_x emission using KOME biodiesel was also found to be reduced by using EGR.     

Effects of EGR,swirl augmentation techniques on combustion of biodiesel/ethanol and their blends in a diesel engine

The diminishing resources and continuously increasing cost of petroleum in association with their alarming pollution levels from diesel engines have caused an interest in finding alternative fuels to diesel which are renewable and sustainable. Emission control and engine efficiency are two most important parameters in current engine design. The impending introduction of emission standards such as Euro IV and Euro V is forcing the research towards developing new technologies for combating engine emissions. The classification of Euro IV and V norms is applicable to heavy-duty engines in Europe, where as Euro 5 is applicable to light-duty engines. This paper presents the effects of exhaust gas recirculation (EGR), swirl augmentation techniques and ethanol addition on the combustion of Honge oil methyl ester (HOME) and its blends with ethanol in a diesel engine. From the experimental work conducted, it is found that the combustion of HOME plus up to 15% ethanol blend in a diesel engine operated with optimised parameters of injection timing 23° Before Top Dead Centre and compression ratio 17.5 results in acceptable combustion emissions and improved brake thermal efficiency (BTE). The addition of ethanol increased BTE with reduced hydrocarbons (HCs), CO and smoke emissions. However, NO _x emissions increased dramatically. Use of appropriate EGR reduces NO _x to acceptable levels. The implementation of swirl augmentation techniques further resulted in increased BTE and considerable reduction in tail pipe emissions such as smoke, HCs, CO and NO _x . The effect of swirl by providing grooves on the piston was taken into consideration to find the overall biodiesel engine performance, which gives scope for further studies.     

Social cost of environmental pollution and application of counter measures through clean development mechanism: in the context of developing countries

The developing countries i.e., the non-Annex-I countries (parties to the Kyoto Protocol but not responsible to any reduction target yet) in the Kyoto Protocol whose economies are in transition are also allowed to reduce GHG emissions. Among these, the countries that have accepted the Kyoto Protocol may be benefited from CDM projects to promote sustainable development. The developed countries i.e., the Annex-I countries (that have signed the Kyoto Protocol & are responsible to have specific GHG emission reduction target) or the investing countries, in return, have privilege to purchase CER credits (in units equivalent to one tonne of CO₂ gas emission reduction) to meet the emission target as specified in the Kyoto Protocol. The key step in understanding about CDM is to grasp the concept of “baseline” and “additionality”. The “Baseline” is the emissions level that would have existed if a CDM project had not happened. The feature of an approved CDM project is that the planned reductions would not occur without the additional incentive provided by emission reduction credits; this concept is known as “Additionality”. According to environmental additionality concept, baseline emission minus project emission is equal to emissions reduction. “Investment Additionality,” ultimately rejected during negotiation of the “Marrakech Accords” and “Financial Additionality,” are the two important concepts. The concept of trading of CER matches to the idea of Pigovian tax (equal to the negative externality and which is considered one of the “traditional” means of bringing a modicum of market forces) in Economics, making pollution more costly to the polluter, as the polluters have negative cost since they save money by polluting; hence, there are supposed negative externalities associated with the market activity. Economic theory predicts that in an economy where the cost of reaching mutual agreement between parties is high and where pollution is diffuse, Pigovian tax will be an efficient way to promote the public interest and will lead to an improvement of the quality of life measured by the Genuine Progress Indicator and other human economic indicators, as well as higher gross domestic product growth. We can seek a level of pollution such that the marginal savings (MS) to one polluting unit from pollution (−MC) is equal to marginal damage (MD) from pollution over the entire population, since pollution is a public bad i.e., MS (x*) = ∑MD_i (x*) where ∑D_i (x) is the total damage. Though the responsibility of reduction in emission does not lie on the non-Annex-I countries, still effort of maintaining global emission balance can be expected equally from developed and developing countries. The responsibilities of Kyoto Protocol are (a) to reduce global GHG emissions, (b) to bring about sustainable development in the developing countries lie on above two groups since its effect on February 16, 2005. Different polluters have different costs of pollution control. The least costly way of controlling pollution from various sources that reflects different costs of pollution control making the set of environmental regulations to achieve the emission target at the lowest cost makes the regulation cost-effective. Though efficiency is not attainable for many regulations, cost-effectiveness is attainable.     

An appraisal of emissions control requirements in the California South Coast Air Basin

The purpose of this study is to evaluate the effect of reductions of reactive organic gases (ROG) and NO_x emissions on short-term O₃ and NO₂ concentrations and annual average NO₂ concentrations in the California South Coast Air Basin. Short-term air quality predictions were obtained by applying the Systems Applications Airshed Model to summer O₃ and autumn NO₂ episodes. Effects of emission controls on annual NO₂ concentrations were estimated using CDM and a new parcel tracking model NOXTRAK. Results for the summer O₃ episode indicate that ROG emission reduction in an effective means for reducing peak O₃ concentrations. NO_x emission reduction imposed in addition to ROG emission reductions are counterproductive in reducing peak O₃ concentrations. The modeling results also suggest that attainment of the 1-h federal O₃ standard requires ROG emission reductions on the order of 80% from 1987 levels. Results for the autumn NO₂ episode indicate that NO_x emission reductions approximating those recommended in a proposed Air Quality Management Plan (about 22%) will result in only small (about 5%) reductions in the peak NO₂ concentrations. ROG emission reduction may be more effective than NO_x emission reduction in reducing the peak NO₂ concentration. For the episode studied, a reduction of 36% in ROG emissions is estimated to result in a reduction in peak NO₂ concentrations commensurate with that required to attain the 1-h state NO₂ standard. Model calculations also indicate that the federal NO₂ standard may not be meet by 1987 at one or two stations, but may blosely approached.     

Mutagenic activity of diesel emission particulate extracts and isolation of the mutagenic fractions

Mutagenic activity in diesel emission particulate extracts was detected by the Salmonella typhimurium/microsome assay. Direct-acting mutagens as well as promutagens requiring metabolic activation were detected. The extracts were fractionated into acidic, basic, and neutral fractions, and the neutral fraction was chromatographed into seven subfractions. Differences in the mutagenic potency of these fractions and subfractions were determined by the Salmonella assay. Fractions containing as yet unidentified compounds, but not polynuclear aromatic hydrocarbons, were found to make a major contribution to mutagenic activity of the extracts.     

Technological feasibility and costs of achieving a 50 % reduction of global GHG emissions by 2050: mid- and long-term perspectives

In this article we examine the technological feasibility of the global target of reducing GHG emissions to 50 % of the 1990 level by the year 2050. We also perform a detailed analysis of the contribution of low-carbon technologies to GHG emission reduction over mid- and long-term timeframes, and evaluate the required technological cost. For the analysis we use AIM/Enduse[Global], a techno-economic model for climate change mitigation policy assessment. The results show that a 50 % GHG emission reduction target is technically achievable. Yet achieving the target will require substantial emission mitigation efforts. The GHG emission reduction rate from the reference scenario stands at 23 % in 2020 and 73 % in 2050. The marginal abatement cost to achieve these emission reductions reaches 150/tCO < sub > 2 < /sub > -eq in 2020 and150/tCO₂-eq in 2020 and 600/tCO₂-eq in 2050. Renewable energy, fuel switching, and efficiency improvement in power generation account for 45 % of the total GHG emission reduction in 2020. Non-energy sectors, namely, fugitive emission, waste management, agriculture, and F-gases, account for 25 % of the total GHG emission reduction in 2020. CCS, solar power generation, wind power generation, biomass power generation, and biofuel together account for 64 % of the total GHG emission reduction in 2050. Additional investment in GHG abatement technologies for achieving the target reaches US6.0 trillion by 2020 and US 6.0 trillion by 2020 and US 73 trillion by 2050. This corresponds to 0.7 and 1.8 % of the world GDP, respectively, in the same periods. Non-Annex I regions account for 55 % of the total additional investment by 2050. In a sectoral breakdown, the power generation and transport sectors account for 56 and 30 % of the total additional investment by 2050, respectively.     

Effects of compression ratio,swirl augmentation techniques and ethanol addition on the combustion of CNG–biodiesel in a dual-fuel engine

The diminishing resources and continuously increasing cost of petroleum in association with their alarming pollution levels from diesel engines has led to an interest in finding alternative fuels to diesel. Emission control and engine efficiency are two of the most important parameters in current engine design. The impending introduction of emission standards such as Euro IV and Euro V has forced research towards developing new technologies for combating engine emissions. This paper examines the effects of compression ratio, swirl augmentation techniques and ethanol addition on the combustion of compressed natural gas (CNG) blended with Honge oil methyl esters (HOME) in a dual fuel engine. The present results show that the combustion of HOME and 15% ethanol blend with CNG induction in a dual-fuel engine operated in optimized parameters at an injection timing of 27° Before Top Dead Centre and a compression ratio of 17.5 resulted in acceptable combustion emissions and improved brake thermal efficiencies. The implementation of swirl augmentation techniques increased brake thermal efficiencies (BTEs) and considerably reduced combustion emissions such as smoke, HC, CO and NO_x. The addition of ethanol also increased BTEs. However, at more than 15% of ethanol in HOME, NO_x emissions increased dramatically.     

Carbon dioxide emissions from cities in China based on high resolution emission gridded data

Based on the China high resolution emission gridded data (1 km spatial resolution), this article is aimed to create a Chinese city carbon dioxide (CO₂) emission data set using consolidated data sources as well as normalized and standardized data processing methods. Standard methods were used to calculate city CO₂ emissions, including scope 1 and scope 2. Cities with higher CO₂ emissions are mostly in north, northeast, and eastern coastal areas. Cities with lower CO₂ emissions are in the western region. Cites with higher CO₂ emissions are clustered in the Jing-Jin-Ji Region (such as Beijing, Tianjin, and Tangshan), and the Yangtze River Delta region (such as Shanghai and Suzhou). The city per capita CO₂ emission is larger in the north than the south. There are obvious aggregations of cities with high per capita CO₂ emission in the north. Four cities among the top 10 per capita emissions (Erdos, Wuhai, Shizuishan, and Yinchuan) cluster in the main coal production areas of northern China. This indicates the significant impact of coal resources endowment on city industry and CO₂ emissions. The majority (77%) of cities have annual CO₂ emissions below 50 million tons. The mean annual emission, among all cities, is 37 million tons. Emissions from service-based cities, which include the smallest number of cities, are the highest. Industrial cities are the largest category and the emission distribution from these cities is close to the normal distribution. Emissions and degree of dispersion, in the other cities (excluding industrial cities and service-based cities), are in the lowest level. Per capita CO₂ emissions in these cities are generally below 20 t/person (89%) with a mean value of 11 t/person. The distribution interval of per capita CO₂ emission within industrial cities is the largest among the three city categories. This indicates greater differences among per capita CO₂ emissions of industrial cities. The distribution interval of per capita CO₂ emission of other cities is the lowest, indicating smaller differences of per capita CO₂ emissions among this city category. Three policy suggestions are proposed: first, city CO₂ emission inventory data in China should be increased, especially for prefecture level cities. Second, city responsibility for emission reduction, and partitioning the national goal should be established, using a bottom-up approach based on specific CO₂ emission levels and potential for emission reductions in each city. Third, comparative and benchmarking research on city CO₂ emissions should be conducted, and a Top Runner system of city CO₂ emission reduction should be established.     

Assessment of uncertainties in greenhouse gas emission profiles of livestock sectors in Africa,Latin America and Europe

The global animal food chain has a large contribution to the global anthropogenic greenhouse gas (GHG) emissions, but its share and sources vary highly across the world. However, the assessment of GHG emissions from livestock production is subject to various uncertainties, which have not yet been well quantified at large spatial scale. We assessed the uncertainties in the relations between animal production (milk, meat, egg) and the CO₂, CH₄, and N₂O emissions in Africa, Latin America and the European Union, using the MITERRA-Global model. The uncertainties in model inputs were derived from time series of statistical data, literature review or expert knowledge. These model inputs and parameters were further divided into nine groups based on type of data and affected greenhouse gas. The final model output uncertainty and the uncertainty contribution of each group of model inputs to the uncertainty were quantified using a Monte Carlo approach, taking into account their spatial and cross-correlation. GHG emissions and their uncertainties were determined per livestock sector, per product and per emission source category. Results show large variation in the GHG emissions and their uncertainties for different continents, livestock sectors products or source categories. The uncertainty of total GHG emissions from livestock sectors is higher in Africa and Latin America than in the European Union. The uncertainty of CH₄ emission is lower than that for N₂O and CO₂. Livestock parameters, CH₄ emission factors and N emission factors contribute most to the uncertainty in the total model output. The reliability of GHG emissions from livestock sectors is relatively high (low uncertainty) at continental level, but could be lower at country level.     

Evaluation of techniques used in the preparation of diesel extract samples for mutagenicity studies

Diesel exhaust particles were used to compare methods and techniques used in the preparation of particulate matter for microbial mutagenesis testing. Investigated in this study were extraction, concentration, and solvent exchange methodologies as they affected recovery of mutagenic material from diesel samples using a Salmonella typhimurium plate incorporation assay. Solvent removal methods applicable for use in determining the mass concentration of extracts were also evaluated. Results indicated that particle samples Soxhlet extracted with dichloromethane yielded higher levels of mutagenic activity than did comparative samples utilizing sonication. No difference was seen between rotary evaporation or Kuderna-Danish macro concentration of extracts to volumes > 50 mL. In comparison of micro concentration techniques to volumes < 10 mL, vortex evaporation was found to be more efficient than a modified micro Kuderna-Danish method in recovery of mass and mutagenicity. Solvent exchanged samples were found to yield higher recoveries of mutagenic activity than samples taken to dryness and then reconstituted in the bioassay solvent. A dry mass weighing procedure utilizing desiccation was found to be more acceptable than either the use of an infrared heat lamp or nitrogen blowdown for solvent removal.     

Heavy metal contamination by Al-fabrication plants in Hong Kong

Leaf samples of six plant species collected from locations near the Al-fabrication plants in Sai Kung, Hong Kong were found to be heavily contaminated by Al, Cd, Pb, Ni, Cu and Zn, as determined by inductively — coupled plasma emission spectrophotometer (ICP). Studies using scanning electron microscope incorporated with X-ray microanalyzer showed that significant amounts of dust, with elevated concentrations of heavy metals, were deposited on the leaf surface. The stomatal pores were partially plugged and the guard cells were distorted. The amount of dust deposition and metal contamination varied significantly among different species. Lantana camara had the highest concentrations of all metals. Washing with deionized water could remove the surficial dust particles and reduce the metal contamination, with a degree of effectiveness depending on plant species and metal species. About 50% of Al and other metals were removed from leaves of L. camara and Fiscus variegata by washing, whereas only 20% removal was recorded in Bauhina variegata, the species had the least dust deposition. The soil samples and Al wastes collected from the same sites also exhibited higher values of total metal concentrations than the control. However, the contents of extractable metals were extremely low and were almost below the limits of detection. Experimental data further suggested that the source of leaf metals was mainly accumulated from metal-enriched aerosols, either from Al-fabrication plants or from automobile exhausts, and contribution from soil was relatively unimportant.     

Drinking water quality: An in vitro approach for the assessment of cytotoxic and genotoxic load in water sampled along distribution system

An in vitro approach was performed to assess the quality of drinking water collected at two treatment/distribution networks located near the source (Plant #1) and the mouth of River Po (Plant #2). The water was sampled at different points of each distribution network, before (raw water) and after the chlorine dioxide disinfection, and in two points of the pipeline system to evaluate the influence of the distribution system on the amount and quality of the disinfection by-product. Cytotoxicity and genotoxicity of water extracts were evaluated in human peripheral lymphocytes and Hep-G2 cells by the use of the micronucleus (MN) test and Comet assay. Raw water samples of both plants induced cytotoxic effects, but not the increases of MN frequency in Hep-G2 cells and in human lymphocytes. Increases of DNA damage in human leukocytes was detected by Comet assay for raw water of Plant #2 at concentration ≥ 0.25 Leq/mL. The disinfection process generally has reduced the toxicity of water samples, even if potential direct DNA-damaging compounds have been detectable in drinking water samples. The proposal approach, if currently used together with chemical analysis, can contribute to improve the monitoring drinking water.     

On the Nexus of SO<Subscript>2</Subscript> and CO<Subscript>2</Subscript> emissions in China: the ancillary benefits of CO<Subscript>2</Subscript> emission reductions

This paper examines the issue of ancillary benefits by linking sulfur dioxide (SO₂) emission to CO₂ emission using a panel of 29 Chinese provinces over the period 1995–2007. In the presence of non-stationarity and cointegrating properties of these two data series, this paper applies the panel cointegration techniques to examine both the long-run and short-run elasticities of SO₂ with respect to CO₂. The major findings are that: (1) there exhibits a stable long-run equilibrium relationship between the SO₂ and CO₂ emission with the long-run elasticity being 2.15; (2) there exists a short-run relationship between these two emissions with the short-run elasticity being 0.04. In addition, following an exogenous shock that causes a deviation from the long-run equilibrium, it would take approximately 15 years for SO₂ emission to revert toward the long-run equilibrium path with an average annual convergence rate of 6.5%; (3) the derived ancillary benefits that is generated from one metric ton of CO₂ emission reduction, are 11.77 Yuan (approximately US1.7) in the short run and 196.16 Yuan (US 1.7) in the short run and 196.16 Yuan (US 30) in the long run. These findings are not only crucial from the econometric modeling perspective, but also have important policy implications.     

Mutagenic and carcinogenic potency of extracts from diesel related environmental emissions: Simultaneous morphological transformation and mutagenesis in BALB/c 3t3 cells

Particulate extracts from six different environmental emission sources were assayed for genotoxic activity in mouse BALB/c 3T3 clone A31-1 cells. All compounds were tested simultaneously for both transforming and mutagenic (induction of ouabain-resistance) potential with and without exogenous metabolic activation in the form of a 9000 × g postmitochondrial hepatic supernatant fraction from Aroclor-1254 induced Fischer 344 rats. Dichloromethane particulate extracts from the exhaust of two light duty diesel engines (Oldsmobile and Nissan), one heavy duty diesel engine (Caterpillar) and one late model gasoline engine (Mustang II) were assayed in an identical manner to particulate extracts from the emissions of a roofing tar pot and a coke oven. No clear dose-dependent responses were observed, but several of the samples showed significant transforming and mutagenic activity. A qualitative ranking system showed the activity of these particulate extracts for either mutagenesis or transformation was: coke oven = Mustang II gasoline engine > Nissan diesel engine > roofing tar. Particulate extracts from the Oldsmobile diesel engine and the Caterpillar diesel engine showed essentially no activity.