Emission inventories from onroad mobile sources

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Emission inventories from on-road mobile sources

• UMESAM WORKSHOP
• IAI-SGPII
• 29-31/03/2004
• Santiago, Chile

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The problem and why it is urgent
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• Urban air pollution poses a significant threat to
  human health and the environment throughout both
  the developed and developing world.
• The issue of urban air quality is receiving more
  attention as an increasing share of the worlds
  population are now living in urban centers and
  are demanding a cleaner urban environment.
• In the majority of the megacities, air quality is
  getting worse as the population, traffic,
  industrialization and energy use are increasing
  and there is much urgency in instituting control
  and preventive measures (Khan, 1997).

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• Preventing pollution problems before they occur
  is usually the most cost-effective method for
  dealing with air pollution.
• From a review of the trends in air quality in
  different cities it is quite evident that
  "history repeats itself. The experience of the
  current megacities in the developed countries is
  now being repeated in the developing countries.
  (UNEP/WHO, 1992)
• The study concludes that there is an immediate
  need to improve the monitoring and emissions
  inventory capabilities in cities.
• These are prerequisites for sound air pollution
  management strategies with the main aim of
  protecting public health (Mage et al, 1996).

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• UMESAMs research efforts will focus on mobile
  sources because motor vehicle traffic is a major
  source of air pollution in urban areas.
• In half of the megacities of the world it is the
  single most important source (UNEP/WHO, 1992).
• It is a major source of four of the six major air
  pollutants (CO, NOx, HC, PM) and also contributes
  to CO2 emissions.
• Road traffic contribution to emissions with
  global air quality effects is not yet clear,
  specially when considering future developments in
  automotive emission standards and technologies
  (Elsom, 1992 Lenz, 1999 MacKenzie, 1994
  Pearson, 2001).

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• Therefore, it is necessary to quantify mobile
  emission levels as accurately as possible with
  appropriate spatial and temporal resolution, for
  both local and global pollutants, and taking into
  consideration future trends in urbanization and
  vehicle technologies.
• Future emission reduction scenarios need to be
  analyzed considering differences between cities,
  by means of flexible and sophisticated tools.

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• There are several models available for mobile
  source emission calculation, designed for
  specific use in US and Europe.
• However, existing emission models are inaccurate
  or inapplicable when applied to most situations
  outside of their intended use areas.

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AIR QUALITY EMISSIONS
Reliable air quality simulation and
ambient concentration predictions with
reasonable accuracy
Spatially and temporally disagregated emission
inventory
Stationary sources
Mobile sources
Biogenic sources
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ON-ROAD EMISSIONS ESTIMATES
Two different approaches can be distinguished in
order to create a refined motor vehicle emission
inventory, in particular for urban areas that
face serious air quality problems
?
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TRAFFIC, EMISSION AND DISPERSION MODELS
Emission inventory for mobile sources
Emission inventory for mobile, stationary
and biogenic sources
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MOTOR VEHICLE EMISSIONS
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What has already been done
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MODEM - Chile

• Go to MODEM presentation

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International Vehicle Emissions Modeling

• Design And Measurements

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IVE Wide world
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The Improved Air Quality Management Process
The above process operates on a 3-year cycle.
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The Improved Air Quality Management Process
The above process operates on a 3-year cycle in
Los Angeles.
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Emissions Inventory

• A critical tool to understand sources of air
  quality problems.
• Needed to develop cost-effective air quality
  improvement plans.
• Motor vehicles are one of the most difficult of
  the emission source to quantify temporally and
  spatially.

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Emission Models

• Designed to estimate vehicle emissions for air
  quality planning
• Models were developed by US EPA, California, and
  Europe
• Inaccurate when applied to most situations
  outside of their intended use areas.
• These models were based on driving factors
  observed in the US, California, and Europe
• These models were not designed to accommodate
  new, significantly different, driving factors
• US EPA funded a new model that allows
  consideration of different driving factors to be
  used in countries outside of USAIVE model

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IVE Modeling Goals

• Define low-cost, easy to use methodologies for
  developing key motor vehicle related data.
• Provide a sophisticated model that is
• Flexible and easy to use.
• Adaptable to multiple international locations.
• Useful for analyzing policy decisions and vehicle
  growth impacts.
• Provides a broad range of criteria, toxic, and
  global warming pollutant data.

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Results

• Have developed data collection methodologies to
  supplement local data that can be completed in
  2-3 weeks using about 12-15 participants.
• Have completed development of a computer based
  emissions model that allows consideration of
  local geographic information, fleet technologies,
  and driving patterns.
• Criteria pollutants, toxic pollutants, and global
  warming gases can be estimated.

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IVE Model

• Can be downloaded from www.issrc.org along with
  users manual and input files for cities studied
  to date.
• There is no cost for the model
• Model requires two key sets of data
• Location file (contains driving pattern,
  start-up, and local data such as altitude and
  such)
• Technology file (describes the technology
  distribution of vehicles operating on the roads
  of interest
• Files from similar cities can be borrowed at
  first until local data can be collected

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Vehicle Starts Produce Significant Emissions

• Start emissions are the extra emissions that
  occur when a vehicle is first started (300 sec).
• Vehicles are started 7-10 times per day depending
  on the country
• These starts represent 20 - 50 of daily
  emissions

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Vehicle in First 300 Seconds
Gasoline LEV Technology
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At 1000-1300 Seconds
Gasoline LEV Technology
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Vehicle in First 300 Seconds
Gasoline LEV Technology
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At 1000-1300 Seconds
Gasoline LEV Technology
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Estimating Vehicle Start Emissions

• Best indicator is vehicle technology and the
  amount of time the vehicle engine has been turned
  off
• A base emission factor is established for each
  vehicle technology and multiplied by a correction
  factor that depends on the time the vehicle
  engine has been turned off.
• The time the engine has been turned off is called
  soak time.
• To estimate average start emissions over a day,
  the number of starts at different soak times must
  be determined.

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Voltage Based Start-Up Monitor
Voltage monitored in cigarette lighter.
VOCE Unit records second by second voltage that
is used to determine driving times and start-up
information.
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Example of Start-Up Results From Santiago, Chile
Soak Period
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Comparison of Santiago and US Start Patterns
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Running Emissions

• Running emissions are emissions that occur while
  a vehicle is being operated and the engine is
  warm (running emissions also occur in the first
  300 seconds, but are accompanied by start-up
  emissions.)
• Vehicles operate on average from 18-30
  kilometers/day
• Emissions depend on the driving pattern of the
  vehicle over the day

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Examples of Average Driving
US24,000 km/yr
Nairobi17,000 km/yr
Santiago16,000 km/yr
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Estimating Running Emissions

• The best indicator of the variance in running
  emissions is vehicle power demand per unit
  vehicle mass
• Power demand/unit mass is the energy required to
  overcome wheel and air friction, air resistance,
  and to handle accelerations divided by vehicle
  mass
• Power demand is not a perfect predictor but
  accounts for about 70 of emission variance
• Engine RPM and average power demand account for
  about 5 of emission variance (we call this
  engine stress).

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Estimating Running Emissions

• A base emission factor is established for each
  vehicle technology and multiplied by a correction
  factor depending upon the driving pattern
• To estimate average emissions, the fraction of
  time that cars operate in different driving modes
  must be determined.

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CGPS Unit for Measuring Driving Patterns
CGPS Antenna
Unit easily carried and used to collect passenger
car, bus, truck, and taxi driving patterns.
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Results Velocity Trace for Santiago, Chile
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Results Velocity Trace for Nairobi, Kenya
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Results Velocity Trace for Los Angeles,
California
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Typical Bus Data (Santiago)
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Vehicle Technology Distribution

• Must understand the distribution of technologies
  that operate on urban streets
• Vehicle registration data can be faulty
• One approach is to collect data directly using
  video cameras coupled with a study of specific
  passenger vehicle, bus, taxi, and truck
  technologies by surveying parked vehicles
• Another approach is to use data collected in the
  I/M program rather than a parking lot survey

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Video Taping of Traffic
Vehicle Count Camera
Occupancy Count Camera
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Parking Lot Survey in Nairobi
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IVE Santiago, Lima

• Go to IVE presentation

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IVE START IAI
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