Global networking for assessment of impacts of global change on plant pests

Global change encompasses changes in atmospheric composition, climate and climate variability, and land cover and land use. The occurrence of these changes and their interactive effects on biological systems are worldwide; thus, an effective global change research and impact assessment program must be based on international and interdisciplinary research and communication. With this in mind, several collaborative research networks with a focus on global change have been established in the biological sciences. They include the Global Change and Terrestrial Ecosystems (GCTE) Core Project of the International Geosphere-Biosphere Programme (IGBP) which aims to predict the effects of global change on terrestrial ecosystems, including agriculture and production forestry. Because of the importance of plant pests (arthropods, microbial pathogens, weeds) as yield-reducing factors in agriculture and as early indicators of global change, GCTE initiated a network Activity on "Global Change Impacts on Pests, Diseases and Weeds" with the overall goal of developing a predictive capability for impact assessment and adaptation. The network's specific objectives, contributing research projects, initial results and future challenges are discussed.     

The Southeastern Aerosol Research and Characterization Study: part 1--Overview

This paper presents an overview of a major, long-term program for tropospheric gas and aerosol research in the southeastern United States. Building on three existing ozone (O3)-focused research sites begun in mid-1992, the Southeastern Aerosol Research and Characterization Study (SEARCH) was initiated in mid-1998 as a 7-year observation and research program with a broader focus including aerosols and an expanded geographical coverage in the Southeast. The monitoring network comprises four urban-rural (or urban-suburban) site pairs at locations along the coast of the Gulf of Mexico and inland, including two moderately sized and two major urban areas (Pensacola, FL; Gulfport, MS; Atlanta, GA; and Birmingham, AL). The sites are equipped with an extensive suite of instruments for measuring particulate matter (PM), gases relevant to secondary O3 and the production of secondary aerosol particles, and surface meteorology. The measurements taken to date have added substantially to the knowledge about the temporal behavior and geographic variability of tropospheric aerosols in the Southeast. Details are presented in four papers to follow.     

Accumulation of organic and inorganic contaminants in shellfish collected in estuarine waters near Pensacola, Florida: contamination profiles and risks to human consumers

We conducted a screening level assessment of contaminants in blue crabs (Callinectes sapidus) and oysters (Crassostrea virginica) from bays and bayous in the Pensacola, FL area. Tissue samples were analyzed for 17 dioxins/furans, 12 dioxin-like PCB (DL-PCBs) congeners, mercury, and various metals. Contaminant levels were compared to screening values (SV) calculated using U.S. EPA recommendations for establishing consumption advisories. All sampling locations exceeded the SV (0.098pgg(-1)) for dioxins/furans/DL-PCBs, based on a Florida-specific consumption rate (46gday(-1)). Arsenic (inorganic), mercury, cadmium, and zinc levels exceeded SVs in samples from select locations, and with the exception of mercury, these locations were generally downstream of known contaminated areas. We also assessed potential human health risks from consumption of these species. Risks to human health were greatest from consumption of crab hepatopancreas, suggesting that consumption of hepatopancreas, whether directly or indirectly, from crabs collected anywhere in the Pensacola Bay region should be avoided.     

Correlation and toxicological inference of trace elements in tissues from stranded and free-ranging bottlenose dolphins (Tursiops truncatus)

The significance of metal concentrations in marine mammals is not well understood and relating concentrations between stranded and free-ranging populations has been difficult. In order to predict liver concentrations in free-ranging dolphins, we examined concentrations of trace elements (Al, As, Ba, Be, Cd, Co, Cu, Fe, Li, Mn, Ni, Pb, Sb, Se, Sn, total Hg (THg), V, Zn) in skin and liver of stranded bottlenose dolphins (Tursiops truncatus) from the South Carolina (SC) coast and the Indian River Lagoon, Florida (FL) during 2000-2008. Significantly higher concentrations of Zn, Fe, Se, Al, Cu and THg were found in skin while liver exhibited significantly higher Cu, Fe, Mn and THg concentrations for both study sites. Mean skin concentrations of Cu and Mn were significantly higher in SC dolphins while higher concentrations of THg and V were found in FL dolphins. In addition, liver tissues in SC dolphins exhibited significantly higher As concentrations while higher Fe, Pb, Se, THg, and V levels were found in FL dolphins. Two elements (Cu and THg) showed significant age-related correlations with skin concentration while five elements (Cu, Se, THg, Zn and V) showed age-related correlations with liver concentrations. Geographic location influenced age-related accumulation of several trace elements and age-related accumulation of THg in hepatic tissue was observed for both sites to have the highest correlations (r² = 0.90SC; r² = 0.69FL). Mean THg concentration in liver was about 10 times higher in FL dolphins (330 μg g⁻¹ dw) than those samples from SC dolphins (34.3 μg g⁻¹ dw). The mean molar ratio of Hg to Se was 0.93 ± 0.32 and 1.08 ± 0.38 for SC and FL dolphins, respectively. However, the Hg:Se ratio varied with age as much lower ratios (0.2-0.4) were found in younger animals. Of the 18 measured elements, only THg was significantly correlated in skin and liver of stranded dolphins and skin of free-ranging dolphins from both sites suggesting that skin may be useful in predicting Hg concentrations in liver tissue of free-ranging dolphins. Results indicate that 33% of the stranded and 15% of the free-ranging dolphins from FL exceed the minimum 100 μg g⁻¹ wet weight (ww) (∼400 dw) Hg threshold for hepatic damage while none from SC reached this level. Hepatic concentrations of As in SC dolphins and V in FL dolphins were also highly correlated with skin concentrations which may have some regional specificity predictive value. The present study provides the first application of trace element concentrations derived from stranded bottlenose dolphins to predict liver concentrations in free-ranging populations.     

The Southeastern Aerosol Research and Characterization Study: Part 1—Overview

Abstract

This paper presents an overview of a major, long-term program for tropospheric gas and aerosol research in the southeastern United States. Building on three existing ozone (O₃)-focused research sites begun in mid-1992, the Southeastern Aerosol Research and Characterization Study (SEARCH) was initiated in mid-1998 as a 7-year observation and research program with a broader focus including aerosols and an expanded geographical coverage in the Southeast. The monitoring network comprises four urban-rural (or urban-suburban) site pairs at locations along the coast of the Gulf of Mexico and inland, including two moderately sized and two major urban areas (Pensacola, FL; Gulfport, MS; Atlanta, GA; and Birmingham, AL). The sites are equipped with an extensive suite of instruments for measuring particulate matter (PM), gases relevant to secondary O₃ and the production of secondary aerosol particles, and surface meteorology. The measurements taken to date have added substantially to the knowledge about the temporal behavior and geographic variability of tropospheric aerosols in the Southeast. Details are presented in four papers to follow.     

Fluoranthene, but not benzo[a]pyrene, interacts with hypoxia resulting in pericardial effusion and lordosis in developing zebrafish

Previous research has documented several PAHs that interact synergistically, causing severe teratogenicity in developing fish embryos. The coexposure of CYP1A inhibitors (e.g. FL or ANF) with AHR agonists (e.g. BaP or BNF) results in a synergistic increase in toxicity. As with chemical CYP1A inhibitors, it has also been shown that CYP1A morpholinos exacerbate BNF-induced embryotoxicity. We hypothesized that a hypoxia-induced reduction in CYP1A activity in BNF or BaP-exposed zebrafish embryos would similarly enhance pericardial effusion and other developmental abnormalities. BaP, BNF, ANF, and FL exposures, both individually and as BaP+FL or BNF+ANF combinations, were performed under hypoxia and normoxia. CYP1A activity in the BaP+hypoxia and BNF+hypoxia embryos was reduced by approximately 60% relative to normoxia embryos. Although CYP1A activity was significantly reduced, we did not observe any increase in pericardial effusion in either group. An unexpected yet particularly interesting result of these experiments was the observed interaction of both FL and ANF with hypoxia. Relatively high, yet environmentally relevant concentrations of FL (100-500 microg L(-1)) interact with moderate hypoxia (7.3% DO) through an unknown mechanism, resulting in pericardial effusion and severe lordosis. Additionally, ANF exposures (100 microg L(-1)) which are not normally teratogenic caused dramatic pericardial effusion, but not lordosis, when embryos were coexposed to hypoxia. These results suggest that reduced CYP1A activity may not exclusively underlie observed developmental toxicity, and that hypoxia may exacerbate the developmental toxicity of some PAH mixtures.     

The Use of Health Risk Assessment to Estimate Desirable Sampling Detection Limits

Abstract

The inclusion of non-detected chemicals in a health risk assessment may lead, in some cases, to estimated risks that exceed regulatory thresholds, because one must use the detection limit or half of the detection limit. This study presents a methodology which will allow one to estimate appropriate detection limits by conducting a health risk assessment prior to the source sampling program. The advantages and shortcomings of various levels of detail in the risk assessment to determine those detection limits are discussed. The application of the methodology is demonstrated with a case study of the potential health effects of power plant stack emissions.     

Biomonitoring and environmental specimen banking

The environmental specimen banking program (ESB) of the Federal Republic of Germany implies a collection of specimens from representative areas of Germany, stored under stable conditions for deferred analysis. It is an important part of the ecological assessment program. The ecological concept is presented as the frame of the entire ESB program. It is based on the selection of representative sampling areas and specimens. Standard operating procedures (SOP’s) for sampling and characterization of specimens, as well as sampling designs specific to the areas, are presented as further important parts of the quality assurance system in relation to the correct sampling of specimens.     

Environmental hazard — Assessment of chemicals and products

Part III: The Limits to Single Compound Assessment The principles and basic assumptions of single compound assessment are briefly reviewed. Limitations to this approach are shown, especially with regard to complex mixtures of similar substances, substitution products, and complicated (final) products containing chemicals and materials produced by the chemical industry. A new thinking in product lines and life cycles is emerging, leading to new assessment methods. In some cases, substitution has not improved the environmental performance of products, since very similar chemicals were used as substitutes.     

Effects of forest management on soil carbon: results of some long-term resampling studies

The effects of harvest intensity (sawlog, SAW; whole tree, WTH; and complete tree, CTH) on biomass and soil C were studied in four forested sites in the southeastern US (mixed deciduous forests at Oak Ridge, TN and Coweeta, NC; Pinus taeda at Clemson, SC: and P. eliottii at Bradford, FL). In general, harvesting had no lasting effects on soil C. However, intensive temporal sampling at the NC and SC sites revealed short-term changes in soil C during the first few years after harvesting, and large, long-term increases in soil C were noted at the TN site in all treatments. Thus, changes in soil C were found even though lasting effects of harvest treatment were not. There were substantial differences in growth and biomass C responses to harvest treatments among sites. At the TN site, there were no differences in biomass at 15 years after harvest. At the SC site, greater biomass was found in the SAW than in the WTH treatment 16 years after harvest, and this effect is attributed to be due to both the N left on site in foliar residues and to the enhancement of soil physical and chemical properties by residues. At the FL site, greater biomass was found in the CTH than in the WTH treatment 15 years after harvest, and this effect is attributed to be due to differences in understory competition. Biomass data were not reported for NC. The effects of harvest treatment on ecosystem C are expected to magnify over time at the SC and FL sites as live biomass increases, whereas the current differences in ecosystem C at the TN site (which are due to the presence of undecomposed residues) are expected to lessen with time.     

Thermoluminescence as a tool for monitoring ozone-stressed plants

The effect of ozone (6 h, various concentrations from 0 to 350 ppb) on barley (Hordeum vulgare L., cv. Bomi) and tomato (Lycopersicon esculentum L., cv. Yellow Cherry) leaves was investigated in parallel by thermoluminescence (TL) and fluorescence (FL) methods. Several significant changes were found in TL glow curves measured after excitation by one single turnover flash at +2 degree C in the temperature range from 2 to 170 degree C immediately after ozone exposure. Contrary to TL, ozone induced only negligible changes in FL parameters F0, FM and Fv/FM. Measurements done 24 h after ozone exposure showed partial recovery of ozone-induced changes. The extent of recovery was not the same in different parts of TL curves. Fluorescence parameters were not significantly changed. The results demonstrate that TL parameters are more sensitive to ozone than conventially used FL parameters F0, FM and Fv/FM. Moreover, TL measurements seem to give information not only about the PSII electron transport, but also about the extent of oxidative damage and membrane lipid peroxidation. It is concluded, that TL can be a highly informative tool for monitoring the impact of ozone on plants.     

Water-related problems of central Asia: some results of the (GIWA) International Water Assessment Program

This paper presents results of the research under the program Global International Waters Assessment (GIWA) for the Aral Sea basin (Subregion 24 of the GIWA program). These results show that the detemining factor for the region is freshwater shortage and the main issue is modification of stream flow. According to GIWA assessment estimations, freshwater shortage is responsible for about 70% of the developmental problems in the region. The current economy is developing under conditions of increasing water deficiency. In spite of increasing efforts by the governments of the countries in the region, and by the international community, the situation in regard to water supply and economic objectives in the countries of central Asia remains tense and shows clear tendencies towards aggravation and conflict. The main causes for this sharpening of ecological and socioeconomic conditions in the region are analyzed, and measures to mitigate stress in transboundary water-resources use are presented.     

Treatment of hydrocarbon contamination under flow through conditions by using magnetite catalyzed chemical oxidation

Soil pollution by hydrocarbons (aromatic and aliphatic hydrocarbons) is a major environmental issue. Various treatments have been used to remove them from contaminated soils. In our previous studies, the ability of magnetite has been successfully explored to catalyze chemical oxidation for hydrocarbon remediation in batch slurry system. In the present laboratory study, column experiments were performed to evaluate the efficiency of magnetite catalyzed Fenton-like (FL) and activated persulfate (AP) oxidation for hydrocarbon degradation. Flow-through column experiments are intended to provide a better representation of field conditions. Organic extracts isolated from three different soils (an oil-contaminated soil from petrochemical industrial site and two soils polluted by polycyclic aromatic hydrocarbon (PAH) originating from coking plant sites) were spiked on sand. After solvent evaporation, spiked sand was packed in column and was subjected to oxidation using magnetite as catalyst. Oxidant solution was injected at a flow rate of 0.1 mL min^?1 under water-saturated conditions. Organic analyses were performed by GC–mass spectrometry, GC–flame ionization detector, and micro-Fourier transform infrared spectroscopy. Significant abatement of both types of hydrocarbons (60–70 %) was achieved after chemical oxidation (FL and AP) of organic extracts. No significant by-products were formed during oxidation experiment, underscoring the complete degradation of hydrocarbons. No selective degradation was observed for FL with almost similar efficiency towards all hydrocarbons. However, AP showed less reactivity towards higher molecular weight PAHs and aromatic oxygenated compounds. Results of this study demonstrated that magnetite-catalyzed chemical oxidation can effectively degrade both aromatic and aliphatic hydrocarbons (enhanced available contaminants) under flow-through conditions.     

Life cycle and economic assessment of source-separated MSW collection with regard to greenhouse gas emissions: a case study in China

In China, the continuously increasing amount of municipal solid waste (MSW) has resulted in an urgent need for changing the current municipal solid waste management (MSWM) system based on mixed collection. A pilot program focusing on source-separated MSW collection was thus launched (2010) in Hangzhou, China, to lessen the related environmental loads. And greenhouse gas (GHG) emissions (Kyoto Protocol) are singled out in particular. This paper uses life cycle assessment modeling to evaluate the potential environmental improvement with regard to GHG emissions. The pre-existing MSWM system is assessed as baseline, while the source separation scenario is compared internally. Results show that 23 % GHG emissions can be decreased by source-separated collection compared with the base scenario. In addition, the use of composting and anaerobic digestion (AD) is suggested for further optimizing the management of food waste. 260.79, 82.21, and ?86.21 thousand tonnes of GHG emissions are emitted from food waste landfill, composting, and AD, respectively, proving the emission reduction potential brought by advanced food waste treatment technologies. Realizing the fact, a modified MSWM system is proposed by taking AD as food waste substitution option, with additional 44 % GHG emissions saved than current source separation scenario. Moreover, a preliminary economic assessment is implemented. It is demonstrated that both source separation scenarios have a good cost reduction potential than mixed collection, with the proposed new system the most cost-effective one.     

Adapting a geographical information system-based water resource management to the needs of the Romanian water authorities

Background, aim, and scope

The need for global and integrated approaches to water resources management, both from the quantitative and the qualitative point of view, has long been recognized. Water quality management is a major issue for sustainable development and a mandatory task with respect to the implementation of the European Water Framework Directive as well as the Swiss legislation. However, data modelling to develop relational databases and subsequent geographic information system (GIS)-based water management instruments are a rather recent and not that widespread trend. The publication of overall guidelines for data modelling along with the EU Water Framework Directive is an important milestone in this area. Improving overall water quality requires better and more easily accessible data, but also the possibility to link data to simulation models. Models are to be used to derive indicators that will in turn support decision-making processes. For this whole chain to become effective at a river basin scale, all its components have to become part of the current daily practice of the local water administration. Any system, tool, or instrument that is not designed to meet, first of all, the fundamental needs of its primary end-users has almost no chance to be successful in the longer term.

Materials and methods

Although based on a pre-existing water resources management system developed in Switzerland, the methodological approach applied to develop a GIS-based water quality management system adapted to the Romanian context followed a set of well-defined steps: the first and very important step is the assessment of needs (on the basis of a careful analysis of the various activities and missions of the water administration and other relevant stakeholders in water management related issues). On that basis, a conceptual data model (CDM) can be developed, to be later on turned into a physical database. Finally, the specifically requested additional functionalities (i.e. functionalities not provided by classical commercial GIS software), also identified during the assessment of needs, are developed. This methodology was applied, on an experimental basin, in the Ialomita River basin.

Results

The results obtained from this action-research project consist of a set of tangible elements, among which (1) a conceptual data model adapted to the Romanian specificities regarding water resources management (needs, data availability, etc.), (2) a related spatial relational database (objects and attributes in tables, links, etc.), that can be used to store the data collected, among others, by the water administration, and later on exploited with geographical information systems, (3) a toolbar (in the ESRI environment) offering the requested data processing and visualizing functionalities. Lessons learned from this whole process can be considered as additional, although less tangible, results.

Discussion

The applied methodology is fairly classical and did not come up with revolutionary results. Actually, the interesting aspects of this work are, on the one hand, and obviously, the fact that it produced tools matching the needs of the local (if not national) water administration (i.e. with a good chance of being effectively used in the day-to-day practice), and, on the other hand, the adaptations and adjustments that were needed both at the staff level and in technical terms.

Conclusions

This research showed that a GIS-based water management system needs to be backed by some basic data management tools that form the necessary support upon which a GIS can be deployed. The main lesson gained is that technology transfer has to pay much attention to the differences in existing situations and backgrounds in general, and therefore must be able to show much flexibility. The fact that the original objectives could be adapted to meet the real needs of the local end-users is considered as a major aspect in achieving a successful adaptation and development of water resources management tools. Time needed to setup things in real life was probably the most underestimated aspect in this technology transfer process.

Recommendations and perspectives

The whole material produced (conceptual data model, database and GIS tools) was disseminated among all river basin authorities in Romania on the behalf of the national water administration (ANAR). The fact that further developments, for example, to address water quantity issues more precisely, as envisaged by ANAR, can be seen as an indication that this project succeeded in providing an appropriate input to improve water quality in Romania on the long term.

     

Air toxics in Canada measured by the National Air Pollution Surveillance (NAPS) program and their relation to ambient air quality guidelines

This study reports ambient concentrations of 63 air toxics that were measured in Canada by the National Air Pollution Surveillance (NAPS) program over the period 2009–2013. Measured concentrations are compared with ambient air quality guidelines from Canadian jurisdictions, and compounds that exceeded guidelines are identified and discussed. Although this study does not assess risk or cumulative effects, air toxics that approached guidelines are also identified so that their potential contribution to ambient air toxics pollution can be considered. Eleven air toxics exceeded at least one guideline, and an additional 16 approached guidelines during the study period. Four compounds were measured using methods whose detection limits exceeded a guideline value, three of which could not be compared with guidelines, since they were not detected in any samples. The assessment of several metal(loid) concentrations is tentative, since they were measured only in fine particulate matter (PM) but compared with guidelines based on coarse or total PM. Improvements to sampling and analysis techniques for the latter compounds as well as for those whose methods are subject to known uncertainties would improve confidence in reported concentrations and their relation to applicable guidelines. Analysis of sampling strategies for all compounds found to exceed or approach guidelines would contribute to ensuring that their spatiotemporal coverage is adequate. Examination of the air toxics not measured by NAPS but having guidelines in Canadian jurisdictions or being included in other programs such as the U.S. National-Scale Air Toxics Assessment (NATA) would contribute to ensuring that the full suite of pollutants relevant to ambient air quality in Canada is subject to adequate study. The results of this study can be applied to evaluating the effectiveness of toxic substances management in Canada.

Implications: Recent measurements of 63 air toxics in Canada by the National Air Pollution Surveillance (NAPS) program showed that 11 compounds exceeded daily or annual ambient air quality guidelines and that an additional 16 compounds approached such guidelines within an order of magnitude. The results of this study can be applied to evaluating the effectiveness of toxic substances management in Canada and to identifying compounds that merit further investigation.     

Hazardous Waste Minimization: Part X The Waste Minimization Assessment: A Useful Tool for the Reduction of Industrial Hazardous Wastes

This article describes the “nuts and bolts” of implementing a waste minimization program at an industrial facility which has made a commitment to carry out such a program for waste reduction and/or elimination. Under EPA sponsorship, a waste minimization assessment methodology has been developed and applied in a total often such assessments at industrial and DOD facilities. The article reviews the eleven distinct steps that represent the preferred procedure for carrying out a waste minimization assessment at an industrial site. This procedure is presented in detail in the recently published “The EPA Manual for Waste Minimization Opportunity Assessments.” Two case studies are presented which have employed this methodology to develop waste reduction options in the areas of source reduction and recycle/reuse. Lessons learned during the development and application of this methodology are also presented.     

Role of extractable and residual organic matter fractions on sorption of phenanthrene in sediments

Two sediments were demineralized and sequentially fractionated into extracted fractions [free lipid (FL), bound lipid (BL) and lignin (LG)] and residual fractions [free lipid free (FLF), bound lipid free (BLF) and lignin free (LGF)]. The sorption isotherms of phenanthrene (Phen) were examined to evaluate the importance of various fractions on sorption. A lignin extraction procedure was for the first time applied to separate the lignin or degraded lignin fraction from sediment organic matter (SOM). The extracted LG was similar to model lignin in terms of elemental ratios and sorption behavior. FL and LG fractions were quite important, as their contents were much higher than reported values. Phen sorption for the extracted fractions was almost linear, whereas that for the residual fractions was nonlinear, especially for LGF with n 0.56–0.63. As the different organic fractions were removed sequentially, sorption energy distribution on the residual sediment organic matter (SOM) became more heterogeneous. In addition, increasing sorption capacity for the residual fractions, except for BLF with its high polarity, suggested that more sorption sites on the SOM matrix became accessible to Phen. The sorption capacity for LGF was comparable to that of condensed SOM. The residual fraction LGF generally controlled the overall sorption at low Phen concentration, but the extractable fraction FL surpassed the former fraction at high Phen concentration, demonstrating the importance of condensed SOM in the sorption of hydrophobic organic compounds (HOCs) in sediments.     

Environmental risk assessment of existing chemicals

Most of the existing chemicals of high priority have been released into the environment for many years. Risk assessments for existing chemicals are now conducted within the framework of the German Existing Chemicals Program and by the EC Regulation on Existing Substances. The environmental assessment of a chemical involves:

1. exposure assessment leading to the derivation of a predicted environmental concentration (PEC) of a chemical from releases due to its production, processing, use, and disposal. The calculation of a PEC takes into account the dispersion of a chemical into different environmental compartments, elimination and dilution processes, as well as degradation. Monitoring data are also considered.
2. effects assessment. Data obtained from acute or long-term toxicity tests are used for extrapolation on environmental conditions. In order to calculate the concentration with expectedly no adverse effect on organisms (Predicted No Effect Concentration, PNEC) the effect values are divided by an assessment factor. This assessment factor depends on the quantity and quality of toxicity data available.

In the last step of the initial risk assessment, the measured or estimated PEC is compared with the PNEC. This “risk characterization” is conducted for each compartment separately (water, sediment, soil, and atmosphere). In case PEC > PNEC an attempt should be made to revise data of exposure and/or effects to conduct a refined risk characterization. In case PEC is again larger than PNEC risk reduction measures have to be considered.     

Fine urban and precursor emissions control for diesel urban transit buses

Particulate emission from diesel engines is one of the most important pollutants in urban areas. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled "Clean Diesel Air Quality Demonstration Program" has been initiated by the New York City Metropolitan Transit Authority (MTA) under the supervision of New York State Department of Environmental Conservation and with active participation from Johnson Matthey, Corning, Equilon, Environment Canada and RAD Energy. Under this program, several MTA transit buses with DDC Series 50 engines were equipped with Continuously Regenerating Technology (CRTTM) particulate filter systems and have been operated with ultra low sulfur diesel (<30 ppm S) in transit service in Manhattan since February 2000. These buses were evaluated over a 9-month period for durability and maintainability of the particulate filter. In addition, an extensive emissions testing program was carried out using transient cycles on a chassis dynamometer to evaluate the emissions reductions obtained with the particle filter. In this paper, the emissions testing data from the Clean Diesel Air Quality Demonstration Program are discussed in detail.