Uncertainties of heavy metal pollution assessment

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Uncertainties of heavy metal pollution assessment

• Oleg Travnikov
• EMEP/MSC-E

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Outline

• Sensitivity and uncertainty analysis
• Models intercomparison
• Model results vs. measurements
• Back trajectory analysis
• Emission reporting for model application

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Model sensitivity analysis
Hg total deposition
Pb and Cd total deposition
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Model uncertainty
Model intrinsic uncertainty without effect of
emissions
Lead and cadmium
Mercury
Uncertainty 20-50
Uncertainty 30-40
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Review of MSC-E models Workshop on review of
MSC-E models on HMs and POPs (Moscow, 2005)
Purpose to establish whether MSC-E models on HMs
and POPs are state of the art and fit for the
purpose of evaluating long-range transport of HMs
and POPs.

• Conclusions ECE/EB.AIR/GE.1/2006/4
• The model parameterization is appropriate for
  operational modelling of heavy metal
  concentration and deposition in Europe
• HM depositions, concentrations and transboundary
  fluxes of HMs calculated by MSC-E model
  corresponded well with other transport models
• Other models, such as the MSC-E model,
  underestimated air and precipitation
  concentrations of Pb and Cd when using official
  emission data

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Model intercomparison
Comparison of MSCE-HM and CMAQ models for Pb and
Cd
CMAQ (Community Multi-scale Air Quality model)
3D chemical transport model developed in US
EPA www.cmaq-model.org

• Conditions of comparison
• Anthropogenic emissions based on official and
  ESPREME data
• Identical meteorological data for 2000
• Similar initial and boundary conditions

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Model intercomparison
Annual mean Cd concentration in precipitation
(2000)
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Wind re-suspension of HMs

• HM re-suspension scheme
• Parameterization of mineral dust suspension
• Marticorena and Bergametti, 1995 Alfaro
  and Gomes, 2001 Gomes et al., 2003
• Parameterization of sea salt aerosol production
• Monahan et al., 1986 Gong, 2003
• Detailed soil properties data
• ISLSCP (Initiative II), http//islscp2.sesd
  a.com
• Measured HM content in soil
• FOREGS, Salminen et al., 2005

Contribution of Pb re-suspension 20 in 1990,
60 in 2005
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Evaluation vs. observations
Annual mean concentration in precipitation based
on official emissions data (2005)
Lead
Cadmium
Mod 0.45 Obs Corr 0.51
Mod 0.70 Obs Corr 0.57
Pb
Cd
20-30 underestimation
30-50 underestimation
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Analysis of discrepancies
Daily mean Cd concentration in air (2005)
Svratouch, Czech Republic (CZ1)
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Analysis of discrepancies
Monthly mean Cd concentration in precipitation
(2005)
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Analysis of discrepancies
Monthly mean Cd concentration in precipitation
(2005)
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Evaluation vs. observations
Hg concentration in air (2005)
Mod 0.94 Obs
Hg
Hg concentration in precipitation (2005)
Mod 0.78 Obs
Hg
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HM emissions reporting
According to submission 2007
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HM emissions by sectors
Cd emissions in large European countries (2005)
According to submission 2007
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Non-Party emission estimates
Comparison of official data with non-Party
estimates of Pb emissions in 2000 (TNO, ESPREME)
Germany
Germany
According to submission 2007
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Emission uncertainty
Emissions data uncertainties reported by
countries (Pb)
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Gaps of HM officially reported emissions data

• Incomplete data on emission totals
• Limited data on spatial distribution
• No data on temporal variation
• Scarce data on emission uncertainty

What data should be used to fill the gaps?
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Summary (1)

• Estimated intrinsic model uncertainty is 30-40
  for Pb and Cd and 20-50 for Hg
• Modelling results are highly sensitive to
  emissions data for Pb and Cd and to boundary
  conditions for Hg
• MSCE-HM and CMAQ models agree in underestimation
  of measurements (up to 70) when officially
  reported emissions data is used
• Assessment of wind re-suspension allows improve
  agreement between modelling results and
  measurements
• Current model-to-measurement comparison
  demonstrates 20-30 underestimation for Pb and
  30-50 underestimation for Cd. Modelling results
  for Hg well agree with observations

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Summary (2)

• Reported emission inventories for heavy metals
  are incomplete and of limited value in terms of
  model applications
• Procedure of the reported emission gaps filling
  is to be elaborated