Figure 1'1 de Nevers

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Figure 1.1 de Nevers

• Sources - Atmospheric phenomena - Receptor Effects

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HEALTH EFFECTS OF AIR POLLUTANTS

• Short-term, high concentration exposures leading
  to acute effects
• Long-term, low concentration exposures leading to
  chronic effects
• Dose-response relationship
• Threshold type
• No-threshold type

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Figure 2.1 de Nevers

• Types of dose-response relationship

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POLLUTANTS AND EFFECTS

• Relation between elevated concentrations of motor
  vehicle related pollutants and respiratory
  problems, morbidity
• Relation between elevated concentrations of motor
  vehicle related pollutants and daily deaths,
  mortality
• Relation between elevated concentrations of motor
  vehicle related pollutants and lifetime cancer
  risk
• Populations at risk

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Health Effects Pyramid
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Trends in Air Pollution (Toronto, 1980-1994)
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So why has air quality become a priority?

• Effects occurring at ambient levels
• Involuntary nature of exposure
• No threshold for effects
• Magnitude of the health effect
• Sensitive groups affected
• Suspect air pollution creates disease
• Knowledge gaps affect controls

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CONCENTRATION, DOSE, EXPOSURE

• Dose C V
• C concentration of pollutant, mass /volume
• usually a function of time
• V volume of inhaled air
• dV/dt, rate of inhalation is a function of
  bodily activity
• Integrated Dose ? C (dV/dt) dt
• Exposure ? C dt

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HEALTH EFFECTS ASSESSMENT

• Animal studies
• expose animals (mice, rats) to the pollutant of
  concern under controlled conditions and observe
  effects, extrapolate results to humans
• Epidemiology
• observe effects in populations of similar
  characteristics except for exposure to the
  pollutant of concern

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PROTECTION OF HUMAN HEALTH

• Occupational health and safety
• Short Term Exposure Limits (STEL)
• Time Weighted Averages (TWA)
• National Ambient Air Quality Objectives (NAAQO)

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MOTOR VEHICLE EMISSIONS OF CONCERN FOR HUMAN
HEALTH

• The pollutants regulated on the basis of human
  health criteria CO, NOx, NMHC, PM10 (PM2.5)
• Non-regulated pollutants, (or aspects) of recent
  (and/or increasing) concern, e.g.
• benzene
• formaldehyde
• acetaldehyde
• 1,3 butadiene
• MMT
• number and chemical composition of PM10

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SOME COMMON TERMINOLOGY

• AIR TOXICS A general term used for VOCs and
  PAHs
• POM Polycyclic Organic Matter, includes PAH but
  not limited to HC
• Inhalable Particles, particles that get past our
  nose and throat, PM10
• Respirable Particles, particles that get past the
  trachea and bronchi, into the lung, PM2.5

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Air Toxics

• Mobile sources are a significant contributor to
  national inventories of several key air toxics
  that are also considered to be urban hazardous
  air pollutants as identified in EPAs Integrated
  Urban Air Toxics Strategy.
• These include 1,3-butadiene, acetaldehyde,
  acrolein, benzene, and formaldehyde.
• In addition, DPMDEOG is emitted virtually only
  from mobile sources.

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What Are Mobile Source Air Toxics?

• Mobile source air toxics are compounds emitted
  from highway vehicles and nonroad equipment which
  are known to cause cancer or other serious health
  and environmental effects. In a 2001 rulemaking,
  EPA identified 21 air toxic compounds emitted
  from mobile sources.

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PARTICULATE MATTER CHARACTERIZATION

• Size
• PM10, PM2.5, PM1.0
• Regulation currently based on mass
• PM emissions from motor vehicles mostly in the
  ultrafine range
• 1000 particles of 0.1 ?m have same mass as a 1 ?m
  particle
• Concern that engine modifications aimed at
  reducing mass of emissions may be increasing
  number of particles

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• Particulate Matter in Air
• PM
• PM10
• PM2.5
• PM1.0
• Ultrafine particles
• The smaller the particles, the deeper they can
  get into our lungs

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Figure 8.9 (8.11) de Nevers

• Atmospheric PM size distribution

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PARTICULATE MATTER CHARACTERIZATION

• Chemical composition
• Elemental carbon, EC, soot
• Organic carbon, OC, adsorbed HCs, PAH etc.
• Soluble Organic Fraction, SOF
• Metals, (from fuel, engine wear, brakes,
  catalyst)
• How do we distinguish the health effects of
  particulate matter due to different aspects ?

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Case Studies

• U.S. EPA Motor Vehicle Related Air Toxics Study
• Canadian Council of Environment Ministers (CCME)
  Sulfur in Gasoline regulation development
• CCME Study on Health Benefits of Motor Vehicle
  Emission Control
• MMT

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EXPOSURE METHODOLOGYU.S. EPA Air Toxics Study

• Types of neighborhood
• Urban residential
• Urban commercial
• Urban industrial
• Suburban residential
• Suburban commercial
• Suburban industrial

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EXPOSURE METHODOLOGYU.S. EPA Air Toxics Study

• Microenvironments
• Indoors, work or school
• Indoors, home or other
• Inside a transport vehicle
• Roadside, street canyons, tunnels, parking
  garages
• Outdoors
• Kitchen

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EXPOSURE METHODOLOGYU.S. EPA Air Toxics Study

• Ambient air quality monitors in urban areas are
  usually placed to avoid undue influence from
  nearby sources, i.e. they attempt to quantify
  overall air quality
• Scaling factors for CO, relative to ambient
  monitoring station data (NAAQS Exposure Model,
  NEM)
• Indoors 0.85
• Transport vehicle 2.10
• Roadside 1.20
• Outdoors 0.95

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CANCER INCIDENCE OR DEATHU.S. EPA Air Toxics
Study

• (EXP C UR C POP ) 70 CAN
• EXP annual average exposure ?g/m3
• UR Unit risk, extra risk of cancer due to
  exposure to a particular pollutant, per ?g/m3
• e.g. 8.3 X 10-6 (?g/m3)-1 quoted for benzene
• POP population
• 70 average life expectancy
• CAN number of cancer incidences or deaths per
  year

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Sulphur-in-GasolineWhat was the issue?

• naturally occurring in crude.
• poisons catalytic converter.
• emissions linked to adverse health effects.
• regulation was called for.
• No Canadian regulations.
• Highest levels in western world.

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Canadian Sulphur Levels - 1998Highest in
Ontario, highly variable between refineries,
independents generally lower
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Sulphur-in-Gasoline (cont.)

• Scientific Panels were established.
• Atmospheric
• Health
• Cost
• Competitiveness
• Panels chosen by all parties
• Panels were independent
• Panels presented findings to multi-stakeholder
  working group

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Atmospheric Panel Findings
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Health Effects Panel
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HEALTH BENEFITS OF MOTOR VEHICLE EMISSION
CONTROL CCME, Hagler-Bailey Study

• Attempt to quantify health benefits (in )
  associated with reduced emissions from motor
  vehicles
• PM10
• Ground-level O3
• (from reduced emissions of NOx and VOCs from
  motor vehicle )
• Air Toxics
• Benzene
• Acetaldehyde
• Formaldehyde
• 1,3 Butadiene

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HEALTH BENEFITS OF MOTOR VEHICLE EMISSION
CONTROL CCME, Hagler-Bailey Study

• Modelling of emission reductions from motor
  vehicles
• PM10 - PART5
• NOx and VOC - MOBILE5
• Air Toxics - COMPLEX MOBILE5

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HEALTH BENEFITS OF MOTOR VEHICLE EMISSION
CONTROL CCME, Hagler-Bailey Study

• Modelling of ambient concentration reductions
• PM10
• Climatological Regional Dispersion Model (CRDM)
• Geographical resolution, USA County, Canada
  Province
• Receptor modelling to estimate fraction of
  ambient PM10 contributed by motor vehicles
• Rollback method assume ambient concentrations
  are proportional to emissions
• Air Toxics
• Rollback method

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HEALTH BENEFITS OF MOTOR VEHICLE EMISSION
CONTROL CCME, Hagler-Bailey Study

• Modelling of ambient concentration reductions
• Ozone
• Regional box model
• Results from UAM modelling in three U.S.A
  regions scaled to predict effect of NOx/VOC
  emission reductions on O3

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• There are many potential economic and social
  consequences associated with adverse health
  effects that result from air pollution,
  including 
• Medical costs. These include personal
  out-of-pocket expenses of the affected individual
  (or family), plus costs paid by medicare or
  insurance, for example.
• Work loss. This includes lost personal income,
  plus lost productivity, whether the individual is
  compensated for the time or not. For example,
  some individuals may perceive no income loss
  because they received sick pay, but sick pay is a
  cost of business and reflects lost productivity.
  Typically, lost income is used as the work loss
  proxy.

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• potential economic and social consequences
  (contd)
• Increased costs for chores and caregiving. These
  include special caregiving and services that are
  not reflected in medical costs. These costs may
  occur because some health effects reduce the
  affected individuals ability to undertake some
  or all normal chores, and because he or she may
  require caregiving.
• Other social and economic costs. These include
  restrictions on or reduced enjoyment of leisure
  activities, discomfort or inconvenience (pain and
  suffering), anxiety about the future, and concern
  and inconvenience to family members and others.

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Economic Measures of the Value of Health Effects

• Cost-of-illness (COI)
• COI measures include only medical costs and lost
  income as a proxy for work loss (consequences 1
  and 2 above)
• Willingness to pay (WTP)
• Total social WTP is the summation of (1) the
  affected individuals WTP to avoid the adverse
  consequences, (2) the WTP of friends and family
  who expend time, effort, and monies caring for
  the affected individual, and (3) the medical and
  work loss costs paid by society rather than by
  the affected individual, family, and friends.
  Because there are few literature values for (2),
  these values are excluded and result in a
  potential understatement of air pollution control
  benefits.

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MMT, methyl cyclopentadienyl Manganese tricarbonyl

• Antiknock fuel additive replacing lead
• Health concerns raised but effects not
  demonstrated
• Motor vehicle manufacturers claim it degrades
  performance of emission control technology (i.e.
  they would not be able to meet new emission
  regulations)
• Ethyl Corp. (sole manufacturer and distributor in
  Canada) disputes both health and engine/emission
  performance concerns
• Both U.S. and Canada (more recently) have had to
  rescind effective bans because they were not
  based on demonstrable health effects

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MMT Issues

• Impact on pollution control technology
• evidence equivocal (EC, EPA)
• Mn as an emission
• phosphate, sulphate, oxide
• Manganese
• essential element at low dose (dietary)
• neurotoxin at high doses

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Manganese toxicity
Exposure
Concentration ng/m3
Group
Health Endpoint
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Mn (MMT) Risk Assessment

• Do Mn air concentrations in Canada represent a
  health threat?
• If so, what is the contribution of MMT use to
  these levels?

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Risk Assessment Protocol(standard)
Risk
Effects
Exposure
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Mn (MMT) Risk Assessment (cont.)

• Toxicity Assessment
• bioavailability, transport, reversibility, age,
  susceptible subgroups
• Exposure Assessment
• multi-media
• ambient and estimated personal exposure levels
  (Mean, 90th, 99th)
• Montreal (high traffic), Hamilton (industrial),
  St. John (small city)

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Mn Reference Value Derivation

• Study with lowest exposure having effect on
  adverse health outcome
• HC, US EPA, WHO used Roels et al. 1992
• Calculation
• extract NOAEL 102 ug/m3 (264 ug/m3yrs /2.6yrs)
• convert to lifetime exposure (x 5/7 x 10/23
  m3/day)
• apply uncertainty factors
• 10 for intraspecies variation
• 10 for less than lifetime exposure
• 100.5 for database limitations
• RfC 0.11 ug Mn/m3

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Risk Assessment Conclusionexposure vs. toxicity

• current levels of airborne manganese to which
  the population of large Canadian urban centres
  are exposed are below the level at which adverse
  effects are expected
• for cities in which there are major
  manganese-emitting industries, average manganese
  exposure is at or above the level at which the
  risk of adverse effects may begin to increase.

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• In April 1996, the Canadian Environment Ministry
  began the process of introducing legislation that
  would ban the import and inter-state transport of
  MMT. In September 1996, Ethyl Corp., which has a
  manufacturing facility in Canada, served notice
  that it would lodge a complaint under the North
  American Free Trade Agreement (NAFTA) for 200
  million damages if the law was passed. Undeterred
  by this threat, the Canadian Parliament voted for
  a ban in April 1997, causing Ethyl to sue for
  251 million of compensation under the NAFTA.

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• In July 1998 however, the Canadian Government,
  perhaps sensing it had a weak case, reached an
  'out-of- court' settlement with Ethyl. The
  Canadian Government agreed to allow Ethyl to
  resume selling MMT in Canada, pay Ethyl 13
  million in compensation and repair any potential
  damage to Ethyl's reputation by stating that,
  MMT poses no health risk.