Appendix 4

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• Appendix 4
• Patrick H. Dyke Inventories for Persistent
  By-Products of Industrial and Combustion Processes

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Inventories for Persistent By-Products of
Industrial and Combustion Processes

• Patrick H Dyke
• Presentation for UNEP Chemicals Workshop Jan 1999

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Introduction

• What and Why
• How
• Available data
• Limitations and Conclusions

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Basic Concepts

• Inventories are estimates of releases of selected
  compounds or groups
• Without knowing the sources how can you control?
• Usually per year
• Used to focus emissions controls - identify the
  low hanging fruit
• Show trends

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Inventory Compilation

• Becoming well established
• However, no universally accepted approach
• Various limitations
• Assumptions make important differences -
  therefore hard to compare one against another
• Moving target!

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Basic approach

• Screen to identify processes of interest
• Generate emissions factors and activity
  statistics
• Annual emission Em factor x Activity statistic
• Compile list of sources

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Top down or bottom up?

• Sector average emissions and total production
• eg 5Mt of MSW incinerated with emission of 5
  micro g/ t 25 g/y
• Plant by plant annual emission summed for all
  plants
• eg a g/y b g/y ... Z g/y
• Will depend on circumstances

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Setting a baseline

• Emissions are changing rapidly
• Must have consistency
• Must recognise technological development
• up-grading of existing plants
• closure of polluting plants
• opening of new plants

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Data handling

• Mass emissions or toxic equivalent?
• Data quantity versus utility?
• Criteria for acceptance/rejection
• Handling of non-detected results
• How to handle categories that cannot be
  estimated?
• What is the end use?

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Data availability

• Most emission test data comes from limited
  countries Germany, Holland, UK, US
• Is it representative?
• Some will be but this cannot be assumed
• Need background information

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Dioxin inventories

• Heidi Fiedlers compilation of inventories
• 15 countries only
• fewer still for releases to land and water
• hard to compare

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1995 Air emissions (H Fiedler),g ITEQ/y
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UK PCDD/F Emissions to Air - 1993
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UK PCDD/F Emissions - future estimate (post 1996)
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contribution in Austria (PCDD/F)
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Germany air emissions PCDD/F g ITEQ/y
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Inventory of PCDD/F

• Some common points
• old MSW incinerators - large source
• metals industry not recognised initially
• Different patterns from country to country
• Rapid changes occurring
• Can be substantial releases to land and in
  products

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US EPA Inventory

• Substantial effort
• Still very uncertain
• Major amount in products

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US EPA PCDD/F (g ITEQ/y) 1998
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Poorly quantified sources

• Landfill fires - 1000 g ITEQ/y
• Backyard trash burning - 1000 g ITEQ/y
• Not included in inventories
• No estimate for several metal processes and in
  particular Magnesium manufacture

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Pointers

• Developed countries controlling emissions from
  MSWI
• Uncontrolled sources become more important
• eg domestic combustion, accidental fires
• Likely to be similar in developing countries
• Products and chemicals?

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Other chemicals

• Wide range
• Not so widely studied
• Some data on PAH, HCB and PCB
• Are they the same sources?
• Are the control techniques the same as for PCDD/F?

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UK PCB releases (1993 base)
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UK PAH emissions t/y
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Draft Canadian HCB emissions (1998 draft, average)
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Conclusions

• We have the tools
• But-
• we need a systematic approach
• we need more data
• we need to be aware of differences between
• countries
• technologies, sites
• year on year changes

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Conclusions (2)

• Resource intensive process to carry out full
  assessments
• Use screening methods
• these must be reflective of regional/local needs
• Be driven by hazard/risk assessment of the
  chemicals to be addressed