The importance of the evaluation of PM102'5 emissions with respect to meeting forthcoming legislatio

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The importance of the evaluation of PM10/2.5
emissions with respect to meeting forthcoming
legislation

• Dr Lesley Sloss
• Senior Environmental Consultant

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First air pollution regulation

• Be it known to all within the sound of my voice,
  whosoever shall be found guilty of the burning of
  coal shall suffer the loss of his head.
• King Edward I, ca 1300

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The solutionParticulate control devices.

• Removal efficiency of particulate systems,
• ESP gt99-99.99
• Fabric filter (baghouse) 99-99.9999
• Wet particulate scrubber 90-99.9
• Cyclones multicyclones 75-99

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Particulate emissions in Germany Poland
Power stations
Mobile
Poland
Germany
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Bonus trace element removal for free.Overall
partitioning of trace elements in a power plant
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Were on a roll what next?

• Fine particulates
• PM10 (under 10 microns in diameter)
• PM coarse (PM10-PM2.5)
• PM2.5 (under 2.5 microns in diameter)
• PM fine (PM2.5)
• PM ultra-fine (below PM1.0)

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Representation of portions of the mass particle
size distribution. (Source Watson. J.G.
(2002))
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• Emission sources of atmospheric particulate
  matter.

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Why?

• Over 20 major studies around the world since 1973
  have indicated a link between fine particulates
  and early mortality.
• Legislation was a foregone conclusion.

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Three main particle deposition mechanisms
occurring within the respiratory tract
(source Yeh et al., 1976.)
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Cause of the health problem?

• Could be any or none of the following
• Size effect
• Morphology
• Chemical effect
• Acidity
• Toxin
• Transition metals
• If we knew, we could refine the legislation
  appropriately.

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For the first time ever

• Ambient air quality legislation has been set for
  a pollutant
• For which the causality is unknown and
• Without a strict chemical definition.

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Impending legislation Europe

• Stage 1 applies from 1st Jan 2005
• 24 hour average 50 Fg/m3
• not to be exceeded more than 25 times/year
• annual average 30 Fg/m3
• Stage 2 applies from 1st Jan 2020
• 24 hour average 50 Fg/m3
• not to be exceeded more than 7 times/year
• annual average 20 Fg/m3

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Impending legislation USA

• PM10 (current)
• 24 hour average 150 Fg/m3
• not to be exceeded more than once/year
• 99th percentile of 24 hour values in a year
• averaged over three years
• annual average 50 Fg/m3
• averaged over 3 years
• PM2.5 (impending)
• 24 hour average 65 Fg/m3
• 98th percentile of 24 hour values in a year (at
  highest monitor) averaged over three years
• annual average 15 Fg/m3
• 3 year average and spacial averaging

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Not really particles at all

• Three main species within PM2.5
• Primary particles
• Secondary particles (aerosols, agglomerates)
• Precursor species (SO2, NOx, VOC)

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The majority of PM2.5 matter in developed
countries is secondary particulates
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Measurement

• Primary particles
• Impactors
• Filters
• Cyclones
• Secondary particles
• Dilution methods and simulation
• Precursors
• Standard methods and simulation
• Dilution methods and simulation

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Modelling

• Atmospheric models must
• Predict the movement and spread of primary and
  secondary particulates and precursors
• Take into account source position, wind direction
  and speed and ambient conditions such as
  temperature and air pressure
• Take into account emissions from all other
  sources - human activities and natural sources

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Global sources of aerosol particulates
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Breakdown of PM2.5 composition in SCAB
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Average contribution to PM2.5 from sources in the
USA
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What sources do we target?

• Each source is contributing to a mix. The mixture
  is reactive and varies with
• location
• temperature
• other species present
• measurement method.
• Legislation against a reactive mix has major
  limitations and problems.

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Complications

• the emissions which lead to elevated
  concentrations of PM2.5 in the Pittsburgh urban
  area originate from Ohio River Valley sources (or
  beyond), far to the west and southwest of the
  city.
• Control of emission sources only within the city
  would not be expected to eliminated many of the
  high PM2.5 episodes seen in Pittsburgh

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So how do we reduce ambient concentrations?

• Most sources of PM2.5 and precursors are natural,
  unavoidable or untouchable

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Control of primary particles?

• We cannot control emissions from natural sources.
• It will be years before we can reduce emissions
  of particles from the transport sector.
• .the majority of the PM2.5 in ambient air is
  secondary material reaction products.

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Control of secondary particles

• Would include control of
• Sulphates
• Nitrates
• ammonia
• Organic species
• Halogens
• Trace elements
• everything.

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Control of secondary particles and precursors at
large sources is possible.

• Improved capture of SO2, NOx and VOC
• Multi-pollutant approaches eg
• - advanced particulate systems
• - activated carbon with advanced ESP or
  baghouses
• - electrostatic gas cleaning systems.

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But will it reduce localised PM2.5
concentrations?

• Not necessarily

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Will it reduce the health effects seen?

• Not necessarily

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Conclusions

• Legislation has been set ahead of scientific
  understanding
• A reduction in health effects will only be
  achieved if the causative agent is identified
• PM2.5 legislation may lead to expensive source
  emission controls which may not achieve the
  desired effects
• Much more work is required in the health studies
  to identify the true culprit