Xun Jin and Karen A. High School of Chemical Engineering Oklahoma State University

1. AICHE 2003 Annual Meeting Nov. 16-23, San Francisco Towards the Best Practice Environmental Sustainability Metrics for Chemical Engineers:Using a Hierarchical Life Cycle Impact Assessment Xun JinandKaren A. High School of Chemical Engineering Oklahoma State University

2. SusCAD

3. Sustainability Concept • Definitions: - Inter/intra-generation equity view - Critical limits view - Competing objective view • Basic characteristics: - Vagueness - Complexity - Transdiscipinarity - Flexibility

4. Difficulties for Chemical Engineers • Conceptual intricacy • Perspective diversity • Knowledge deficiency • Relevancy emphasis ? ? ?

5. Conventional Environmental Performance Metrics Desired Environmental Sustainability Metrics Load Impact Short-term, local Long-term, global (regional) Physical and chemical Biological and ecological impact Discrete Systemic Static Dynamic Nature Science Social science Metric Transformations • Paradigm shift: “Greening” to “Sustaining” - NAE & NRC (1999)

6. Best Practice Metrics • Is there a set of best practice metrics in general ? - Impossible “no-size-fits-all” - Trade-offs between desired features, cost and feasibility - Lack of systematization • What will help? - Identified endpoint(s) and the pertinence to the endpoint(s) - A well-defined assessment framework that allows operational diversity - A scientifically sound classification

7. ? Human welfare (Sustainability) CO2 SO2 NOx HCFC VOC Acrylonitrile Environment Air Concentration increment Water Soil Plant Endpoint and Causality • Causality represents the relevancy to sustainability • Traditional isolated endpoints ignored the integration of the environment • Extended endpoint

8. Endpoint = “Human Welfare” ? • Bad • - Still Fuzzy • - Less defendable environmental relevancy • Good • - Independent to the subsystems • - Endpoint reflects maximum relevance, provide an important criterion to evaluate alternatives • - A universal endpoint, “Canary in coal mine” or common currency

9. Assessment Framework • LCA is the best candidate - Well-developed theoretical framework - Prosperous resources and applications • Provides no default metric • Variety in metric selection

10. Handling Variety • A multi-level hierarchy could potentially tackle the inconsistency and classify the metrics • Existing frameworks include:

11. Well-being Integrality Effect Immune system suppression Marine life damage Crop damage Material damage Global warming Skin Cancer Cataracts Increased UVB Destroyed ozone Status Released Cl-, Br- A SSEIW Hierarchy • Stressor: The discharges associating with a given human activity • Status: The induced state change of the exact environmental compartment that the stressors are directly exerted on • Effect: The resulting environmental impacts that embody certain aspect of societal concern • Integrality: Component completeness, structural rationality and functionality of the environment as a whole • Well-being: The damages caused by all the prior aspects to human welfare Impact CFCs emission Stressor

12. I Define impact category II Identify category indicator III Select characterization model VI Classification V Characterization VI Normalization VII Grouping VIII Weighting Impact assessment LCA Framework I Define impact category II Identify category indicator III Select characterization model VI Classification V Characterization VI Normalization VII Grouping VIII Weighting

13. Well-being Integrality Effect Immune system suppression Marine life damage Crop damage Material damage Global warming Skin Cancer Cataracts Increased UVB Destroyed ozone Status Released Cl-, Br- Operational Issues • Bottom-up vs. Top-down - Bottom-up The target problem is analyzed first without a concrete goal. This approach may not be adequate for the achievement of specific goals, mostly adopted by scientists, engineers and other people who is interested in the performance of the particular system - Top-down The top-down scheme starts with defining the assessment goals and aims to evaluate the accomplishment of specific goals. The limitation of this approach is that pre-defined goals sometime have to be compromised with indicator availability. Mostly applied by managers, environmentalists, policy-makers Top-down Bottom-up CFCs emission Stressor

14. (categorized by environmental mechanisms) Radiative forcing increase Photochemical ozone formation …… Ozone layer depletion (categorized by direct societal interests) Respiratory system effect Sea level increase Marine life effect …… (categorized by ecosystem concern) Biodiversity Ecosystem health …… Ecosystem resilience Operational Issues (cont.) • Two-dimensional Impact Categorization Across the causal chains Status Effect Along the causal chains Integrality

15. Operational Issues (cont.) • Indicator and characterization model selection - Compatibility of the indicators across multiple levels depends on how to utilize them in decision-making - Develop a characterization model

16. Example • Ground level ozone formation

17. Example (cont.) • Different metrics of measuring environmental sustainability

18. Conclusion • Keep an open mind • “Best practice” is: - Goal satisfaction at allowable cost with available resources - Apply Life Cycle Assessment theoretical framework - Maximize sustainability relevancy in a valid manner - Customize metrics according to the proposed hierarchy - Effective decision-making paradigm • The future research: - Case study - Human welfare indicator - decision-making using pareto optimality concept

19. Acknowledgement • Environmental Institute @ OSU

20. Questions……