PollutionCosts 20ALEF10 20Rabl

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					                         External Costs of Air Pollution
                                 Ari Rabl, ARMINES/Ecole des Mines de Paris
                                  ari.rabl@gmail.com and www.arirabl.org
                                                October 2010
                                           External Costs
                       = cost that are not taken into account by the market
                          e.g. damage costs of pollution, if polluter does not pay,
                                     = costs imposed on others

                 perspective of society  perspective of individual
  Need government regulations to internalize external costs
     (make polluter take into account the external cost,
       i.e. act as if polluter and victims were the same)
Part of the damage costs are already internalized by current regulations, and some economists define external cost as only that part of the damage cost that
still remains to be internalized (but that is difficult to determine and very uncertain). In practice most people now refer to the entire damage cost of pollution
as “external cost”.

                 Sources of Pollution
                           Most air pollution,
                   (and a large part of all pollution)
is directly or indirectly linked to energy (electricity, heat, transport)

                   Combustion of fossil fuels:

                   CO2 ( global warming)
        NOx ( acid rain, tropospheric O3, health impacts)
              SOx ( acid rain, health impacts)
          black smoke, particles ( health impacts)

                         nuclear waste
    CFCs (insulation, refrigeration) ( stratospheric O3 hole)
           land use (power plants, mines, wastes, ...)
               accidents (mines, Chernobyl, ...)
     thermal pollution ( effects on aquatic ecosystems)
                              etc …                                         2
     Pollution data France

Source: http://www.citepa.org/emissions/nationale
Pollution data France, cont’d

                                Mais le CO2

                How much is clean air worth?
Difficult choices(high costs):
         pay extra for clean energy?
         "zero emission" vehicles?
                   fuel cell car?
         improved flue gas treatment?
                   e.g. catalytic reduction of NOx
         close a factory with high pollution?
                   cancers or jobs?
Excessive spending for environmental protection takes money away
  from other worthy causes, such as education and public health
               Cost-benefit analysis (CBA)
      can help optimize allocation of scarce resources,
   i.e. compare costs and benefits of pollution abatement
              pollution abatement = measures to reduce pollution   5
              Cost-Effectiveness Analysis (CEA)
        = Ranking of abatement measures in terms of their result/cost ratio.
             Example: CO2 abatement in EU by 2020 (reference: IIASA, GAINS model)
Each segment of the curve represents marginal cost (€/tCO2) and contribution to abatement (GtCO2/yr)
of a particular abatement measure, e.g. replacement of incandescent lighting by fluorescent.

                                                                                CEA does
                                                                                 not tell us
                                                                               how far we
                                                                                for that we
                                                                                  need to
                                                                                know also
                                                                               the benefits
Criteria for Determining Optimal Level of Pollution
1) Zero pollution: Unrealistic, our economy could not function
2) Precautionary principle: no useful guidance
3) Stay below threshold of harmful impacts:
OK if there is such a threshold (often the case for ecosystem impacts)
but for many pollutants/impacts there is no such threshold,
e.g. greenhouse gases, health impacts of NOx, PM, SO2, O3,
carcinogens, …
4) Minimize the total social cost Ctot(E) = Cdamage(E) + Cabatement(E)
as function of pollution emission E
        Marginal damage cost = - marginal abatement cost
                      dCdamage      dCabatement
                         dE           dE

              The Precautionary Principle
  only a general guideline (“Think before you act!”),
           no advice for specific problems

    Must be used with a great deal of precaution,
         to avoid unexpected consequences
 e.g. Overestimating risks of nuclear implies increased global
             warming and conventional pollution
Overestimation of mortality costs of pollution implies increased
      mortality through indirect impacts (“poverty kills”)
                  Whose risks, whose precaution?
    We need expectation value of damage costs,
except for cases where valuation is very non-linear function of damage (e.g.
                very large accident, or irreversible damage)
                   Optimal level of pollution, cont’d
                        Example: costs of CO2
Costs [% of GWP]

                                                                          General case (almost always):
                    Cdam                                                   Marginal abatement cost
                    Cab                                                        decreases with E

1%                                                                        Typical case for classical air
                                                                        pollutants: Marginal damage cost
                                                                                    = constant
       0      5    10       15            20        25           30
 dC/dE                                             [Gt CO2/yr]           for CO2: Marginal damage cost
100    CO2]                                                                    increases with E

                                                                        At optimum

                                                                      dCdamage      dCabatement

   0                                                                    dE            dE
       0      5    10       15            20        25           30
                                               [Gt CO2/yr]
           Towards an answer:
the ExternE Project Series of the EC
          ExternE = “External Costs of Energy”
                  Series of research projects
   funded by European Commission DG Research, since 1991
                  (until 1995 with ORNL/RFF)
             >200 scientists in all countries of EU
              (A. Rabl is one of the key participants)
          Major publications 1995, 1998, 2000, 2004

    1) Life Cycle Analysis of fuel chain (LCA)
 2) Site specific Impact Pathway Analysis (IPA)

 Impact Pathway
 to calculate damage
of a pollutant emitted
      by a source

Impacts are summed
over entire region that is
affected (Europe)
and all damage types
that can be quantified:
•loss of agricultural
•damage to buildings
and materials
  €/kg of pollutant
 Multiply by kg/kWh
   to get €/kWh

     Pathways for Dioxins and Toxic Metals
   For many persistent pollutants (dioxins, As, Cd, Cr, Hg, Ni, Pb, etc)
ingestion dose is about two orders of magnitude higher than inhalation

                  Life cycle analysis (LCA)
Relation between impact pathway analysis and current practice of most LCA,
            illustrated for the example of electricity production.

LCA should include site-specific IPA with realistic exposure-response functions
  and monetary valuation - but that’s usually not done in current practice.
                          Comparison of tools
              for evaluating environmental policy options
                              Very limited and simplified list

Tool                                              Description                         Monet.
Life Cycle Assessment      Methodology for a standardised description of                   no
(LCA)                        systems and their environmental burdens;
                          LCA inventory accounts for all stages of a process
Cost-Effectiveness        Costs and results (quantity of pollution that is avoided)        no
Analysis (CEA)             of options are quantified and ranked according to
                                            ratio result/cost
Multi-Criteria Analysis   Stakeholder consultation to determine preferences                no
(MCA)                      among different results and choose best option.
                          MCA is particularly useful when quantification of
                                        costs is problematic
Impact Pathway             Analysis of the chain emission  dispersion                    yes
Analysis (IPA)                     dose-response function  cost
Cost-Benefit Analysis     Evaluate and compare costs and benefits of options               yes
               Monetary valuation
                 For non-market goods:
  based on Willingness-to-pay (WTP) to avoid a loss
           VSL = “Value of Statistical Life”
  (a better name VPF = value of prevented fatality)
= WTP to avoid risk of an anonymous premature death
         typical values used in EU and USA 1-5 M€
 Value of a Life Year (VOLY) due to air pollution = 50,000 €
        Cancers 2M€/cancer, based on VSL = 1 M€

 Methods for valuation of non-market goods:
 • Contingent valuation (survey of individuals)
 • analysis of consumer choices (e.g. lower rent for noisy
 apartments, travel cost, higher wage for higher risk, etc)    15
        Nonmonetary criteria (for multicriteria analysis)
  Some impacts cannot be quantified in monetary terms at the present time
               need other criteria for making decisions
                         Example: risk comparisons
 suppose a "100 year scenario" where nuclear is used for 100 years to produce all
             electricity, 2104 TWh/yr, for a world population of 1010.
                                                                      Days of life lost, per person per lifetime
                                                                    0.01     0.1         1        10        100    1000

 The "100 year                            Car accidents, France

scenario" would
                           Pedestrians killed by cars, France
increase exposure
by  0.1% of                                    Lightning, France
by  1% of                     Fatal hunting accidents, France

cosmic ray                    Deaths due to terrorism, France
background at sea
level               Air pollution in Paris, if increase by 10%

                             Radiation background 2.5mSv/yr

                          Nuclear pow er for w orld for 100 yr
          Information Needs of Policy Makers

Environmental policies need to target specific pollution sources
General policies, e.g. ambient air quality standards, are not sufficient

   Policy makers must tell each polluter how much to reduce the
emission of each pollutant (e.g, NOx from cars = precursor of O3 and
     They need to know impact of emitted pollutant

For some decisions the also need LCA results, e.g.
•choice between nuclear and coal,
•electric or fuel cell vehicle (“pollution elsewhere vehicles”),
•hydrogen economy

           Impact categories of concern
                              Due to pollution
•Global warming
•Health impacts
•Damage to buildings and materials
•Loss of agricultural production
•Acidification and eutrophication
•Reduction of visibility
•Storage of waste (no problem if done “correctly”)
                           Due to other burdens
•Visual intrusion
•Employment (already internalized?)
•Depletion of resources (is it an external cost?)
•Land use
•Nuclear proliferation and risks of terrorism (no cost estimate)   18
                           Comparison LCIA  ExternE
                           Impact 2002+                ExternE
Monetary valuation              no                        yes                  Impact 2002+ is the most
Pollutants considered       All for which   CO2,CH4,N2O,PM,SO2,NOx,VOC,            complete LCIA
                           emissions data        As, Cd, Cr, Hg, Ni, Pb,
                              available      dioxins, benzene, radionuclides      (life cycle impact
Impact categories                                                                     assessment)
Human toxicity                   X                         X
Global warming                   X                         X
                                                                                  Impact 2002+,
Ionizing radiation               X                         X
Photochemical oxidation          X                         X
                                                                                  like most LCA:
Terrestrial acid/eutroph         X                         X                   no monetary valuation,
Land use                         X                         X                     and tries to include
Ozone layer depletion            X                                             everything (even if the
Aquatic ecotoxicity              X
Terrestrial ecotoxicity          X
                                                                                DRFs are dubious)
Aquatic acidification            X
                                                                                   upper bound,
Aquatic eutrophication           X                                                whereas ExternE
Non-renewable energy             X                                             focuses on items with
Mineral extraction               X
Agricultural losses                                        X
                                                                                 the largest damage
Buildings and materials                                    X
                                                                                cost, trying to be as
Accidents                                                  X                    realistic as possible
Energy supply security                                     X                    expectation value.
Amenity impacts                                            X                                    19
Amenity (Visibility, Visual Impact, Noise, Recreation,…)
          No good data on monetary valuation in Europe
                    Quite important in USA
                          Visual impact
              Very local and extremely site-specific,
                          not quantified
              Very local and somewhat site-specific
          ExternE 1995: Some estimates for power plants
             ExternE 1998: Some estimates for wind
            ExternE 2004: first estimates for transport
                           To continue
                   Recreation (Hydro power)
 ExternE 1995 and 1998: quantified for sites in France and Norway,
                   but extremely site-specific

    Accidents, employment,
   resources, supply security
       ExternE 1995, 1998: Nuclear
      ExternE 2004: fossil fuel chains
            Already internalized?
Would need complicated analysis of entire economy
 So far not taken into account by ExternE
             Supply security:
         ExternE 2004: in progress
         Depletion of resources:
   To what extent already internalized?
 So far not taken into account by ExternE           21
                  Land use, waste storage
                                  Land use:
Serious impact on ecosystems and biodiversity
(biodiversity decreases if size of an ecosystem is reduced, e.g. if it is cut by a
Very site-specific.
           So far not taken into account by ExternE
              but new work in NEEDS project …

        Storage of waste (nuclear and conventional):
Difficulty: damage depends on future management of
with new technologies leakage during the operation of the
facility is negligible, but what will happen in the future?
                        need scenarios
 ExternE: assessment of waste storage for nuclear, but so far
                    not for fossil fuel chains
                           Nuclear power
       ExternE 1995 and 1998: Very low damage costs
        (lowest of all except wind, solar and for some sites hydro)
                                    but …
        Risks of nuclear proliferation and terrorism:
Temptation to increase profit and economies of scale by selling the technology to
                      countries that lack sufficient safeguards
                (the link nuclear power -> military is undeniable)

                 Risks of major nuclear accident:
   ExternE 1995: Extremely small with new technologies, but public

                    Long term storage of waste:
No problem as long as storage site is supervised. But is our society stable
                       enough in the long term?

              Risks imposed on future generations:
                      nuclear waste vs. CO2                                    23
          Health impacts of pollution
                PM, NOx, SO2, VOC, O3:
Quantified by ExternE, with continuing updates due to progress of

               As, Cd, Cr, Hg, Ni and Pb:
            ExternE 2004: dose, including food chain
               Cancers due to As, Cd, Cr, and Ni
                   Neurotoxic impact of Pb

                   Organic carcinogens:
 ExternE 2000: cancers due to dioxins, benzene, formaldehyde,
                  butadiene, benzo(a)pyrene

             Quantified by ExternE 1995 and 1998

       All updated by the NEEDS project [ExternE 2008]              24
       Air Pollutants and their effects on health
Primary Pollutant   Secondary                        Impacts
    particles                    Cardio-vascular and respiratory morbidity:
(BS, PM10, PM2.5)                 reduction of lung capacity, lung cancer,
                                             asthma, bronchitis
                                   (hospitalization, sick leave, doctor visits, …)

                                            Direct effects of SO2?
      SO2                                         Mortality
                                  Cardio-vascular and respiratory morbidity
      SO2            sulfates                     like particles?
      NO2                                  direct effects of NO2?
                                          Mortality and morbidity?
      NOx            nitrates                     like particles?

     Are the observed impacts due to particles or due to NO2 or SO2?
       Air Pollutants and their effects on health, cont’d
     Primary Pollutant            Secondary                   Impacts

         NOx+VOC                    ozone                   mortality
                                                      respiratory morbidity
            VOC                                 little or no direct effects at typical
 (volatile organic compounds)                  ambient concentrations (except PAC)

       Benzene, PAC                                           cancers
(polycyclic aromatic compounds)

             CO                                             mortality
                                                    cardio-vascular morbidity
           dioxins                                  Cancers, other morbidity
       As, Cd, Cr, Ni                               Cancers, other morbidity
           Hg, Pb                                 morbidity (neurotoxic, other)

                    Health effects of air pollution

Healthy individuals have sufficient reserve capacity not to notice effects of pollution,
but the effects become observable at times of low reserve (during extreme physical
                     stress, severe illness, or last period of life)

                                                       Pollution reduces reserve capacity

                                                        Mortality impact is not the loss
                                                        of a few months of misery at the
                                                       end but the shrinking of the entire
                                                       quality of life curve (“accelerated

                                                          In large population there are
                                                       always some individuals with very
                                                       low reserve  impacts observable

   Approaches to measure health impacts
1) Epidemiology:
   comparing populations with different exposures.
2) Laboratory experiments with humans:
    exposure in test chambers with controlled concentration of
    air pollutants (but this approach is very limited because of
    ethical constraints).
3) Toxicology:
a) Expose animals (usually rats or mice) to a pollutant; sample
    sizes are usually very small compared to epidemiological
    studies, and the animals are selected to be as homogenous
    as possible (unlike real populations). Extrapolation to
b) Expose tissue cultures to pollutants. Extrapolation to real
    organism???                                               28
Approaches to measure health impacts, cont’d
      Epidemiology: can measure impacts on real
        human populations, by observing correlations
     (“associations”) between exposure and impact. But
   in most cases the uncertainties are very large. Is the
    impact due to the pollutant or due to other variables
   that have not been taken into account (the problem of
            “confounders”, especially smoking)?

   Toxicology: can identify mechanisms of action of
   the pollutants. For many substance tests with animals
     are the only way to identify carcinogenic effects.
     Toxicology can also suggest new questions to be
               investigated by epidemiology.
         The two approaches are complementary.              29
   Dose-response functions (DRFs)
(for air pollutants also known as exposure-response or
           concentration response functions)
     Crucial for calculating impacts of a pollutant.
a) most epidemiological studies do not report explicit
DRFs but only a relative risk (= increase in
occurrence of a health impact due to increase of
exposure). To obtain DRF one also needs data on
background rates of occurrence.

b) Watch out for consistency of DRF with the
specification of exposure (calculated by dispersion
models) and with monetary valuation. E.g. is exposure
specified as hourly peak or as 24 hr average?            30
    Form of dose-response functions (DRF) at low doses

Possible functional forms at low
     Linearity without
is the most plausible assumption
      for NO2, PM, O3, SO2, and
         carcinogens (including

               Difference between DRFs for individuals and for populations
    Toxicology: small samples of identical individuals  threshold
    Epidemiology: real populations with large variations of sensitivity  often no threshold
          Importance of Mortality
 In terms of costs, the most important emitted pollutants
            (apart from greenhouse gases) are
           SO2 (precursor of sulfate aerosols),
           NOx and VOC (precursors of O3).

About 65% of their total damage cost is due to mortality!
          About 15% due to chronic bronchitis,
        About 15% due to other health impacts,
 Only a few % due to agricultural losses, and damage to
Loss of Life Expectancy due to Air Pollution

In EU and USA typical concentrations of PM2.5 around 20 - 30
               g/m3  LE loss 8 months
   Reasonable policy goal during coming decades:
              reduction by about 50%
     Life expectancy (LE) gain about 4 months
     Other countries, e.g. China: concentrations ~2 to 3higher
                    total LE loss ~2 to 4 years

   To put this in perspective with other public health risks:
        Smokers lose about 5 to 8 years on average
                            Rule of thumb:
     each cigarette reduces LE by about the duration of the smoke
    Air pollution (in EU and USA) equivalent to about 4
      How to measure the impacts and costs
             of air pollution mortality

 Key issue for environmental policy because most of total damage
                  cost of pollution is due to mortality

                   Loss of life expectancy  VOLY
                        VOLY = Value of a Life Year
???                             or                                             ???
                       Number of deaths  VPF
      VPF = Value of Prevented Fatality (=VSL = “Value of Statistical Life”)
      = “willingness-to-pay to avoid an anonymous premature death”

      VPF used for accidents, Loss of LE for public health
                     Number of deaths  VPF:
                      mediagenic but wrong
1) VPF based on accidents (large LE loss/death)  air pollution
 2) True number of air pollution deaths is not knowable (at current state of science):
• “air pollution death” = death advanced by air pollution
                              not a primary cause of death
• Cohort studies cannot distinguish if observed mortality due to everybody
    losing a little or a few a lot
           if everybody loses some LE, all deaths are “air pollution deaths”

•   The calculation of number of deaths from cohort studies is wrong because it
    does not take into account change in age structure during future years

•   Number of deaths from conventional time series studies includes only acute
    effects (very small LE loss compared to total)

3) Total LE loss due to pollution can be determined                            35
             Other Effects of Air Pollutants
Primary Pollutant     Secondary                Impacts
   NOx+VOC              ozone      Damage to plants and ecosystems,
                                      damage to some materials
      NOx                              Damage to ecosystems
                                    (Acidification, eutrophication)
       SO2            acid rain    Damage to plants and ecosystems
                                     damage to some materials
    particles                            Soiling of buildings
 CO2, CH4, N2O,                            Global warming
     CFCs                           Destruction of stratospheric O3

Global warming, causes

                  Global temperature and sea level, past

From: http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-ts.pdf
                                                                        Scenarios and
                                                                     temperature change

SRES = Special Report on Emission Scenarios
                                              From: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf
 in precipitation

   For the A1B scenario and
 comparing the period 2080 to
  2099 with the control period
         1980 to 1999

From: http://www.ipcc.ch/pdf/assessment-
report/ar4/wg1/ar4-wg1-chapter11.pdf       40
                Physical impacts of global warming
                CO2 concentration                    Global T          Sealevel rise
Date                  PPM                               C                   cm
1990                  354                                0                    0
2000                  367                               0.2                   2
2050                463-623                     0.8-2.6                     5-32
2100                  478-1099                         1.4-5.8              9-88

           Ref: http://www.ipcc.ch/pub/wg2TARtechsum.pdf (Table.TS-1)
                       Pre-industrial concentration = 280 ppm

  •Changes of heating and cooling
  •Changes of agricultural production
  •Increased incidence of tropical diseases (malaria, dengue fever, …)
  •Migrations of displaced populations
  •Extreme weather events (costs = ??)
  •Ecosystem impacts: species extinction, … (costs = ????)
  •Social and political problems, especially in poor countries (costs = ????)
  •Changes in ocean circulation (could be abrupt, ~years)

                          Some will gain but most will lose                             41
             Monetary valuation of global warming
                              Various estimates for 2xCO2
                 loss on the order of 1 to 2 % of gross world product

                                  Cost per ton of CO2
             depends on discount rate and other controversial assumptions
especially “value of life” in developing countries (where most of the damage will occur)

     For low discount rates the mainstream estimates are around of 10 €/t of CO2
                          (but is it agreement by imitation?)

                               Valuations by ExternE

                                  ExternE 1998:
                 Calculations by ExternE team: 3.8-139 €/tCO2
           18-46 €/tCO2 (“restricted range”, geometric mean 29 €/tCO2 )

                             ExternE 2000: 2.4 €/tCO2

                          ExternE 2003-2008: 19 €/tCO2                           42
Global warming cost, recent estimates by UK
                        Studies in 2004 and 2005
               (literature review and detailed modeling)
   dCdam /dE
                Upper bound

   150          central

                Low er
   100          Low er bound

    50                                      40

      2000        2010           2020      2030      2040   2050

                          Report by Stern et al in 2006
                          Damage cost around 85 €/tCO2             43
Current emissions and implications of a CO2 tax

                                                  Germany 10 tCO2/yr
                                                   France 6 tCO2/yr

                                                   If tax = 20 €/tCO2:
                   QuickTime™ and a
                                                       for 6 tCO2/yr
                  BMP decompressor
            are neede d to see this picture.         per per person
                                                    cost = 120 €/yr
                                                  per person (France)
                                                 Implication for electricity
                                                (note current average price
                                                     ~7 cents/kWh):
                                                  gas (combined cycle)
                                               0.4 kg/kWh0.8 cents/kWh

                                                   coal (steam turbine)
                                               0.9 kg/kWh1.8 cents/kWh
         Stabilization at 550 ppm                               44
       What do to about global warming?

Reduce emissions
   •Shift to renewables or nuclear
   •Increase efficiency of fossil energy use
   •carbon sequestration (storing CO2 in depleted reservoirs
   of natural gas or oil, in aquifers, deep ocean, …)

Adaptive measures to reduce impacts, e.g.
  •develop drought resistant crops
  •change crops
  •build dikes

Impacts and Technologies evaluated by ExternE
1) Global warming (CO2, CH4, N2O)
2) NOx, SO2, PM etc (primary & secondary pollutants)
    •Health (morbidity: ~ 30% of total cost
     mortality: ~65% of total cost, other than global warming)
    •Buildings & materials
    •Agricultural crops
    •Global warming
    •Beginnings of analysis for acidification & eutrophication
    Other burdens
    •Amenity (noise, visual impact, recreation)
    •supply security

•Energy: coal, lignite, oil, gas, biomass, PV, wind, hydro, nuclear
•Waste incineration
•Transport: cars, trucks, bus, rail, ship, (planes)                   46
          Key Assumptions of ExternE
               Local + regional dispersion models

  Linear dose-response functions for health (no threshold):
                        Mostly PM2.5, PM10, O3
                        A few for SO2 and CO
                             None for NO2
       Sulfates are assumed like PM10, Nitrates like 0.5  PM10
                    also As, Cd, Cr, Hg, Ni and Pb

 Mortality in terms of LLE (loss of life expectancy) rather than
                       number of deaths

Monetary valuation based on Willingness-to-pay (WTP) to avoid
                           a loss:
    Value of a Life Year (VOLY) due to air pollution = 50,000 €
            Cancers 2M€/cancer, based on VSL = 1 M€
(VSL = “Value of Statistical Life” = WTP to avoid risk of an anonymous
    premature death; typical values used in EU and USA 1-5 M€)
            Damage Cost per kg of Pollutant,
        and uncertainty (error bars and probability distribution)
                         0.1        1           10          100       1000        10000


     PM2.5, rural          21.5

     PM2.5, highway        159

     PM2.5, Paris          2191

    Power plants,h=100m

     PM10, rural           6.8

     PM10, urban           15.4

     PM10, Paris           65

     SO2, direct, urban 0.6

     SO2, via sulfates     10.2

                         0.1        1           10          100       1000        10000
Note: somewhat different numbers in different publications (due to progress in methodology)
                   Results for Power Plants
Typical numbers for Central Europe [ExternE 2004]. Market price ~7cents/kWh

                                                         Results for Cars
                                     Years Of Life Lost (YOLL) per million km
                               due to air pollution emitted by cars and due to accidents
                                                                            (old data ~ 2000)


From: JV Spadaro & A Rabl 2001. “Damage Costs due to Automotive Air Pollution and the Influence of Street Canyons”. Atmospheric Environment, vol.35 (28), 4763 – 4775.
                                             Results for Waste Treatment
                  Net impact very dependent on energy recovery. Some examples:
                                               Incineration, Baseload heat (H=g&o)                       €/t w aste

                 Direct emissions                                                                                             NOX

               Energy recovery                                                                                                SO2

            Materials recovery
                                                                                                                                      Energy recovery
  -25    -20          -15              -10     -5
                                                    Incineration, no energy recovery
                                                              0          5         10         15        20
                                                                                                             €/t w aste
                                                                                                                                      H = heat
                                                                                                                                      E = electricity
                                                                                                                                      g= gas
                                                                                                                                      o = oil
               Direct emissions

               Energy recovery                                                                                                SO2     c = coal
           Materials recovery                                                                                                 Trace


  -25    -20          -15              -10     -5            0           5          10        15        20            25

                                                    landfill, Baseload Electricity (E=c&o)                       €/t w aste                  Compare with
                                                                                                                                             private costs:
                   Direct emissions
                                                                                                                           SO2                Incineration
                  Energy recovery                                                                                          NOX               ~ 100€/twaste
               Materials recovery                                                                                          CO2+CH4
   -25     -20           -15             -10        -5           0           5           10        15         20           25
                                                                                                                                              ~ 50€/twaste
Other = toxic metals (mostly Hg and Pb) and dioxins (very small with current regulations)
Energy policy: e.g. nuclear, gas or coal?
Transport policy: e.g. how large is benefit of reducing
traffic in cities?
Fuel cell vehicles with H2?
Waste treatment: incineration or land fill?
                 How much recycling of what?
Regulations: optimal emission limits for power plants,
vehicles, factories, agriculture, …
Optimal level of pollution taxes
Optimal level of tradable permits

          How much is clean air worth?
            Do cost-benefit analysis!
     Atmospheric models for damage costs
There are many different models for atmospheric dispersion and chemistry, with
                             different objectives: e.g.
microscale models (street canyons),
local models (up to tens of km),
regional models (hundreds to thousands of km),
short term models for episodes,
long term models for long term (annual) averages.
   For damage costs of air pollution, note that the dose-response functions for
      health (dominant impact) are linear  only the long term average
                            concentration matters

For agricultural crops and buildings they are nonlinear, but can be characterized
     in terms of seasonal or annual averages  only the long term average
                             concentration is needed
Dispersion of most air pollutants is significant up to hundreds or thousands of km
 need local + regional models for long term average concentrations
            (they tend to be more accurate than models for episodes)

Dispersion of
Air Pollutants

     Depends on
    wind speed and
 atmospheric stability
 class (adiabatic lapse
 rate, see diagrams at

Gaussian plume model
   for atmospheric dispersion
    (in local range < ~50 km)

               Gaussian plume model,
                 concentration c at point (x,y,z)
 Underlying hypothesis: fluid with random fluctuations around a dominant
                    direction of motion (x-direction)

                                                         C=concentration, kg/m3
                                                         Q=emission, kg/s
                                                         v= wind speed, m/s,
                                                            in x-direction
                                                         y=horizontal plume width
                                                         z=vertical plume width
                                                         he=effective emission height

                                                         Source at x=0,y=0

                                     2               2
                  Q           1y         1 (z-he) 
   c(x,y,z) = 2 š y z v exp- 2 y  exp- 2  z  
                                                  

Plume width parameters y and z increase with x                             56
           Gaussian plume width parameters
         There are several models for estimating y and z as a function of
                               downwind distance x,
                        for example the Brookhaven model

        a  x                                  a  x
                        by                                        bz
         y       y                                z        z


     To use model one needs data for wind speed and direction,
     and for atmospheric stability (Pasquill class);
     the latter depends on solar radiation and on wind speed.

Gaussian plume                  virt ual
 with reflection
                                                                                               ref lect ion
                                                  X                                         at mixing layer

 When plume hits
 ground or top of
 mixing layer, it is
                                                          z          PLUME
                       PLUME                                        CENTERLINE
                                                               he =effective
                                           stack height        source height

                                                                         ref lect ion
                                                                         at ground
                                virt ual

      Gaussian plume with reflection terms, cont’d
The z exponential of gaussian plume is replaced according to

                                              1 (z - he) 
                                                          
                             S(z) =   exp -               2
                                              2  z  
                                                          

                 
                      1 (z + 2 j H - he)                            
                                                     1 (z + 2 j H + he)  
                                                                     
              exp -           z        2 + exp -         z       2  
                     2                          2                  

the sum going ov er j = 0, ±1, ±2, ...

for 1.08 < z/H (this is th e limit of large distances)
                         2 š z
       replace S(z)  H
this corresponds to uniform vertical mixi ng

                Effect of stack parameters

PLUME                                                       CENTERLINE

                 RELEASE                  he

   Plume rise:
   fairly complex, depends on velocity and temperature of flue gas, as well as
   on ambient atmospheric conditions

                  Effect of stack parameters, examples
            Influence of Emission Source Parameters and Meteorological Data on
               Damage Estimates. The Source is Located in a Suburb of Paris.
      Normalized Damage

                                                                    Reference State
                    Stack height                                    Stack height = 100 m
                                                                    Exit temp = 473 K
                                                                    Exit speed = 10 m/s
                                                                    Exit diameter = 2 m
                                                                    Meteo data are
                                                                    average values for
                                                                    the period 1987-92.
                                   Exit temperature
           Exit diameter


 1         Exit speed

                                               Weather data


      0                    0,5                        1       1,5         2                2,5
                                                                    Normalized Parameter   61
   Removal of pollutants from atmosphere
Mechanisms for removal of pollutants from atmosphere:
1) Dry deposition
    (uptake at the earth's surface by soil, water or vegetation)
2) Wet deposition
    (absorption into droplets followed by droplet removal by
3) Transformation
    (e.g. decay of radionuclides, or
    chemical transformation SO2 NH4)2SO4).
They can be characterized in terms of deposition velocities,
(also known as depletion or removal velocities)
vdep = rate at which pollutant is deposited on ground, m/s
(obvious intuitive interpretation for deposition)
vdep depends on pollutant
determines range of analysis: the smaller vdep the farther the pollutant travels)
                Typical values 0.2 to 2 cm/s for PM, SO2 and NOx

                 Gaussian plume model can be adapted to include
                             removal of pollutants
                Regional Dispersion, a simple model
    Far from source gaussian plume with reflections implies vertically uniform
    Therefore consider line source for regional dispersion
    (at large r point source and line source produce same distribution)
    f()  = fraction of time when wind in directions  to  + 


                                                    r        

        Simple model for regional dispersion
Consider emission of pollutant as a series of discrete "puffs"
travelling with velocity v() in directions  to  + 

c(r, ) = (annual) average concentration at (r, ) is  n(r, ) = number of
      puffs, per area per time, that cross shaded area r  H (averaged over year)
                               f ( ) f ( )
                   n(r,  )           
                                r H    rH
where f() = frequency of wind direction 
Each puff decays because of deposition or transformation of pollutant
                                   source


                                                  r        

                Simple model for regional dispersion, cont’d
Consider mass balance as puffs move from r to r+r
mass flow v c(r,) H r  across shaded surface at r
= mass flow v c(r+r,) H (r+r)  across shaded surface at r+r
+ mass vdep c(r +r/2,) r (r+r/2)  deposited on ground between r and r+r
Taylor expand c(r+r,) = c(r,) + c’(r, ) r and neglect higher order terms
 Differential equation c’(r, ) = - ( + 1/r) c(r,) with  = vdep/(v H)

    Solution c(r,) = c0 exp(- r)/r with constant c0 to be determined
     (c0 and 
    depend on )

           Simple model for regional dispersion, cont’d
     c0() is proportional to frequency f() of wind in direction ,
     hence set c0() = c0f f()
     Determination of c0f by considering integral of flux c(r,) v() over cylinder of
          height H and radius r in limit of r 0
     This integral must equal to emission rate Q [in kg/s].
     Hence                                          c f ( )exp( r)
                                                            
                 2                           2
     Qlim                  rHc(r,  )v( )d lim                    rH   0f
                                                                                                  v( )d
          r0       0                                  r0       0                       r
     Qc 0 f H                   f ( )v( )d
                          0

     Note normalization                  1       0
                                                       f ( ) d
     and relation with average wind speed                             v               f ( )v( )d
                                                                                  0

     Therefore final result
                 Q f ( ) exp( r)                                                 v dep
      c(r,  )                                                       with    
                  v H       r                                                    v( )H
          Simple model for regional dispersion, cont’d

     Special case: uniformity in all directions f() =1/(2)

                          Q exp( r)
                 c(r) 
                        2 v H  r

     This model can readily be generalized
     (i) To case where wind speeds in each direction are variable with a
     distribution f(v(), )
                                             
                                     2        
   with normalization      1
                                        d        f (v( ), )dv

 (ii) To case where trajectories of puffs meander instead of being straight
 lines: then exp(- r) is replaced by exp(- t(r)) where t(r) = transit time to r;
 all else remains the same.
                         Chemical Reactions
            Primary pollutants (emitted)  secondary pollutants
             aerosol formation from NO, SO2 and NH3 emissions.
            OH                   NH3           Sulfate
  SO2                    H2SO4                 aerosol
           H 2O 2

                                                         Note: NH3 background,
                                                         mostly from agriculture
Emission   Dry dep osition   Wet dep osition

                        Ozone formation
                              Very simplified:

                 light, NOx and VOC O3
                  (VOC = volatile organic compounds)
Really many complex nonlinear processes.
A few of the most important reactions
  NO2 + h  O + NO                and O + O2 + M  O3 + M
where M is a molecule such as N2 or O2 (participation is necessary because of
    the law of conservation of energy).

VOCs prevent the ozone formed from being immediately consumed by NO to
   produce NO2
                   NO + O3  O2 + NO2
VOCs enable the transformation of NO into NO2 without consuming ozone.

          Nonlinearity of ozone formation
   Approximately linear with VOC, but nonlinear with NOx

              Nonlinearity depends on VOC concentration
 optimal strategy for reducing O3 production depends on climate
and on existing levels of VOC and NOx
             UWM: a simple model for damage costs

  Product of a few factors (dose-response function, receptor density,
            unit cost, depletion velocity of pollutant, …),
      Exact for uniform distribution of sources or of receptors

      UWM (“Uniform World Model”) for inhalation
• verified by comparison with about 100 site-specific calculations by
EcoSense software (EU, Eastern Europe, China, Brazil, Thailand,
• recommended for typical values for emissions from tall stacks, more
than about 50 m (for specific sites the agreement is usually within a factor
of two to three; for ground level emissions damage much larger; apply
correction factors).
UWM for ingestion is even closer to exact calculation, because
food is transported over large distances average over all the areas
where the food is produced  effective distributions even more uniform.

 Most policy applications need typical values (people tend to use site
    specific results as if they were typical  precisely wrong rather than
                               approximately right)
                                   UWM: derivation
     total damage D = integral over all receptor sites x = (x,y)

              DsDR        (x)c(x) dxdy
               c(x) = c(x,Q) = concentration at surface due to emission Q Q
               (x) = density of receptors (e.g. population)
               sDR = slope of dose-response function
     Total depletion flux (due to deposition and/or transformation)
   F(x) = Fdry(x) + Fwet(x) + Ftrans(x)
     Define depletion velocity k(x) = F(x)/c(x) [units of m/s]
     Replace c(x) in integral by F(x)/k(x)
     If world were uniform with
     uniform density of receptors  and uniform depletion velocity k
             D(sDR  /k)  F(x) dxdy
                         By conservation of mass         F(x) dxdyQ
      “Uniform World Model” (UWM) for damage

                       Duni sDR  Q/k
                            UWM: example

Mortality (YOLL = year s of life los t) due to SO2, with
sDR = 5.34E-06 YOLL/(pers·yr·µg/m )
depletion ve locity k = 0.01 m/s for SO2
aver age population density = 1.05E-4 persons/m2
emission Q = 1 t/yr = 3.09 E04 g/s

         5.34E-06 YOLL/(pers·yr·µg/m3 ) 1.05E-4 person/ m2
Duni =                       0.01 m/s                       3.09E04 g/s

     = 1.78E-03 YOLL/yr

                  UWM and Site Dependence, example
      dependence on site and on height of source for a primary pollutant:
damage D from SO2 emissions with linear dose-response function, for five sites in France,
in units of Duni for uniform world model (the nearest big city, 25 to 50 km away, is indicated
in parentheses). The scale on the right indicates YOLL/yr (mortality) from a plant with
emission 1000 ton/yr. Plume rise for typical incinerator conditions is accounted for.
        D/Duni                                                                  YOLL/1000 t
                                                          Porcheville (Paris)           10

         5                                                Loire-sur-Rhone (Lyon)

                                                          Albi (Toulouse)

         4                                                Martigues (Marseille)
                                                          Cordemais (Nantes)
         3                                                Duni



         0                                                                               0
             0          50           100            150               200             250     74
                                      Stack Height [m]
                 Validation of UWM, for primary pollutants
       Comparison with detailed model (EcoSense = official model of ExternE)

           Damage costs in € 2000 per kg


           Factor of two


                                 Northern Europe   Central Europe        Sourthern Europe
                                 Southeast Asia    USA                   South America

    0.01                   0.1                1                     10             100
                                                                     Detailed model 75
                            UWM for secondary pollutants
     Same approach: add a subscript 2 to indicate that concentration, dose-response
                function and damage refer to the secondary pollutant
                       
     D2 = sDR2 dx dy (x) c2(x)

     Replace c2(x) by remov al flux F2(x) and removal velo city k2(x)

     c2(x) = F2(x)/k 2(x)

     In a unifo rm world with k2(x) = k2,uni and (x) = uni
          sDR 2 uni
     D2 
            k 2uni
                             dx  dy F (x)

          sDR 2  Q2
     D2 
     because surface int egral of r emoval flux F2(x) equal s the total quantity of
     secondary pollut ant Q2 that h as been created

   Q2 = dx dy F2(x)
                                                                                    76
                      UWM for secondary pollutants, cont’d
     Let us relate Q2 to the emission Q1 of the primary pollutant:
     define a creation flux F1-2(x) as mass of secondary pollutant created per s and per
     m2 of horizontal surface
     F1-2(x) = k1-2(x) c1(x)
     where k1-2(x) is a factor defined as local ratio of F1-2(x) and c1(x).
     Integral over the creation flux F1-2(x) is also equal to th e total quant ity of the
     secondary pollut ant

     Q2 = dx dy F1-2(x) = dx dy k1-2(x) F1(x)/k1(x)
                           

     If uni form atmo sphere with k1-2(x) = k1-2 and k 1(x) = k1 ind ependent of x
            k12                       k12
     Q2 
                    dx  dy F1(x)     k1

     Therefore UWM for secondary pollutants

           sDR2  Q1                                     k 2 k1
    D2                          with          k2eff 
             k2eff                                       k12
                                       Dependence on site and stack height
                                       for primary and secondary pollutants
                                    note: far less variation for secondary pollutants,
                          because created far from source (hence less sensitive to local detail)

                                                                                                              Cordemais (Nantes)
           Sulfates                                                                                           Albi (T oulouse)
                                                                                                              Loire-sur-Rhone (Lyon)
                                                          NO stack height                                     Porcheville (Paris)


        SO2 (x 10)

                                                                    Stack height       Stack height           Stack height
                                                                       250 m              100 m                   1m

Particulates (PM10)

                      0        10000      20000   30000     40000            50000   60000            70000    80000         90000          100000

                                                                                                                 ECU per ton of pollutant
                       Correction factors for UWM
                 for dependence on site and stack height

Pollutant                                         Correction factors
globally dispersing poll utants such as CO2;      1 for all sites
pollutants for which non -inhalation pathways     - 0.7 to 1.5
dominate (dioxin, Pb, As)
nitrates (due to NOx) and sulfates (due to SO2)   - 0.5 to 2.0 for site
                                                  (higher values i f larg e population near source)
Inhalation impacts o f primary pollutants         -0.5 to 6 for site
                                                  (higher values i f larg e city near source),
                                                  -0.6 to 15 for stack height
                                                  (higher values f or low stacks, especially in big

        For example, the cost/kg of PM2.5 emitted by a car in Paris is about 6 * 15
        = 90 times Duni (a factor 6 for variation with site and a factor 15 for
        variation with stack height).

                         Parameters for UWM
  UWM parameters for several countries and regions, based on fits to EcoSense
                   [Spadaro, personal communication].

                          Primary pollutants      Secondary pollutants
                                 k [cm/s]               k2eff [cm/s]
                  [per                             NO2          SO2 
                          PM10    SO2       NO2
Source location   km2]                             Nitrates      Sulfates
EU (central)       80     0.67    0.73      1.47    0.71          1.73
Scandinavia        20     0.67    0.73      1.47    0.71          1.73
Cyprus             54     0.64    0.77      1.27    0.84          1.36
Czech Rep.        111     0.89    0.87      1.04    1.26          2.15
Estonia            43     0.93    1.00      1.67    1.29          1.35
Hungar y          101     0.85    0.94      1.53    1.01          1.77
Latvia             55     0.93    1.00      1.67    1.29          1.35
Lithuania          62     0.93    1.00      1.67    1.29          1.35
Poland            100     0.86    0.89      1.05    1.29          1.98
Poland             89     0.86    0.90      0.96    1.23          2.00
Slovakia          101     0.85    0.94      1.53    1.01          1.77
Slovenia          105     0.85    0.94      1.53    1.01          1.77
Spain              55     0.67    0.73      1.47    0.71          1.73
China             200     0.74    0.66      0.96    0.97          0.90
                             Conclusions, 1

Methodology for calculation of external costs of pollution is well-established
(IPA + inventory of LCA)
In principle should be same as LCIA (life cycle impact assessment) but current
     practice of most LCIA is inconsistent with IPA of ExternE
Results for the most important air pollutants are available
with applications to almost all important technologies for
    • Electricity production
    • Transport
    • Waste treatment
External costs were very large;
now reduced thanks to new environmental directives,
but still significant, especially due to CO2
   Can be used for identifying the most cost-effective policies for reducing
                          Conclusions, 2
    External cost of classical air pollutants mostly due to mortality (~65%)
•   Valuation of air pollution mortality of adults must be based on LE change,
    not number of deaths
•   VOLY = 40,000 €
•   LE change can be determined with sufficient accuracy from long term
    studies ( >10 years)
     LE loss from permanent exposure to 10 g/m3 of PM2.5 ~ 0.4 year
     (in US and EU typically 15-25 g/m3 of PM2.5  like 4 cigarettes/day)

                       Uncertainties are large
factor of about 3 for the classical air pollutants
factor of about 4 for toxic metals
factor of about 5 for greenhouse gases

                       Major sources of uncertainty
Modeling of environmental fate
Dose-response functions for health
Monetary valuation of mortality                                          82
                        Conclusions, 3
 Some people think that the uncertainties of ExternE estimates are too
                           large to be useful
1) Better 1/3 x to 3 x than 0 to 
2) What matters is not the uncertainty itself, but the social
cost of a wrong choice:
a) Without cost estimates such costs can be very large, but with ExternE
they can be remarkably small in many if not most cases.
b) For many yes/no choices the uncertainty is small enough not to affect
the answer.

3) Uncertainties can be reduced by a) research and b)
guidelines by decision makers on monetary values
               (purpose of cost-benefit analysis:
              make public choices more consistent)                    83

1 ppb O3 = 2.00 g/m3 of O3, 1 ppb NO2 = 1.91 g/m3 of NO2, 1 ppb SO2 = 2.66 g/m3 of SO2, 1 ppm CO = 1.16 mg/m3
of CO (all at 20C)
BS = black smoke (fumées noires)
c = concentration
CBA = cost-benefit analysis
CFC = chlorofluorcarbon
CV = contingent valuation
DRF= dose-response function (also known as exposure-response function or concentration-response function CRF)
EC = European Commission
ECU = European currency unit (before 1999) = Euro (since 1999)
GWP = global warming potential (kg of substance with same radiative forcing as 1 kg of CO2)
IPA = impact pathway analysis
IPCC = international panel on climate change
LCA = life cycle assessment (ACV = analyse de cycle de vie)
LE = life expectancy (espérance de vie)
LLE = loss of life expectancy
Morbidity impacts = impacts on health
Mortality impacts = increased number of deaths
NMVOC = non-methane volatile organic compounds
NOx = unspecified mixture of NO and NO2
PMd = particulate matter, with subscript d indicating that only particles with aerodynamic diameter below d, in m, are
included (PSd = poussières en suspension)
rdis = discount rate (taux d’actualisation) = rate at which one is neutral between a payment P0 today
                 and a payment Pn = P0 (1+rdis)-n in n years from now
sDR = slope of DRF (also called sCR = slope of CR function)
UWM = uniform world model for simplified approximate calculation of typical impacts and damage costs
vdep = deposition velocity of pollutant (also called k = removal or depletion velocity) [m/s]
VOC = volatile organic compounds (COV = composantes organiques volatiles)
VOLY = value of a life year
VPF = value of prevented fatality (= VSL = “value of statistical life”)
YOLL = years of life lost                                                                                               84
•ExternE 2000. “External Costs of Energy Conversion – Improvement of the Externe Methodology And Assessment Of
Energy-Related Transport Externalities”. Final Report for Contract JOS3-CT97-0015, published as Environmental
External Costs of Transport. R. Friedrich & P. Bickel, editors. Springer Verlag Heidelberg 2001.
•ExternE 2004. Project NewExt “New Elements for the Assessment of External Costs from Energy Technologies”.
European Commission DG Research, Contract No. ENG1-CT2000-00129. Coordinated by R. Friedrich, IER, University
of Stuttgart. Final report. http://www.externe.info
•ExternE 2005. ExternE – Externalities Of Energy: Methodology 2005 Update. Available at http://www.externe.info
•Rabl A & JV Spadaro 2000. "Public Health Impact of Air Pollution and Implications for the Energy System". Annual
Review of Energy and the Environment, vol.25, 601-627.
•Rabl 2004. “Pathway Analysis for Population-Total Health Impacts of Toxic Metal Emissions”. Risk Analysis,
vol.24(5), 1121-1141.
•Rabl A, J. V. Spadaro & B. van der Zwaan 2005. “Uncertainty of Pollution Damage Cost Estimates: to What Extent
does it Matter?”. Environmental Science & Technology, vol.39(2), 399-408 (2005).
•Rabl A, Spadaro JV and Zoughaib A. 2008. “Environmental Impacts and Costs of Municipal Solid Waste: A
Comparison of Landfill and Incineration”. Waste Management & Research, vol.26, 147-162 (2008).
•Spadaro JV & A Rabl 2008. “Estimating the Uncertainty of Damage Costs of Pollution: a Simple Transparent Method
and Typical Results”. Environmental Impact Assessment Review, vol. 28 (2), 166–183.

 EcoSense = software            of   ExternE     for    detailed   site-specific    calculations.    Available     at
 RiskPoll = software for simplified calculation of typical impacts and damage costs. Available at


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