concept mv by linfengfengfz

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									Estimating On-Road Vehicle Emissions Using CONCEPT




                                        Alison K. Pollack
                                            Ralph Morris
                       ENVIRON International Corporation

                                                   .        1
                    Overview

• WRAP On-Road Emissions Estimates for
    Regional Haze Modeling
•   CONCEPT Overview
•   CONCEPT MV Inputs Required
•   CONCEPT MV Emissions Approach & Steps
•   Summary of Key Differences Between SMOKE
    and CONCEPT MV
•   Denver Example Application and comparison of
    SMOKE vs CONCEPT approaches


                                                   2
On-Road Mobile Emissions Estimates -
         General Approach
      Local Parameters
             Temperature
          Fuel Specifications                  MOBILE6.2
          Control Programs
                                               Generates g/mi
       Vehicle Registration                   Emission Factors




                    Local Travel Data
               Vehicle Miles Traveled (VMT)
      X        and Speed by Roadway Type
                                              =    Emissions
                     VMT Growth Rates


                                                                 3
   WRAP On-Road Emissions Estimates
                    (2002, 2008, 2013, 2018)
• Regionally consistent estimation methods
• Surveyed State/Local Agencies for Most Up-to-Date
  Detailed Inputs
  – 2002 Base year inputs and VMT
  – Future year inputs, VMT growth
  – Unpaved road VMT
  – Responses were received from all state agencies and key local
    agencies
• Estimated County-level Emissions
• Emissions Were Processed Using SMOKE
  – Spatial allocation using Census TIGER roadway mileage
  – Temporal allocation of emissions using temporal profiles for
    activity data
                                                                    4
CONCEPT vs. SMOKE for On-Road Mobile

• SMOKE
  – Emissions are estimated using county-level activity data
  – Can use day/hour-specific county average
  – Useful for areas where detailed link data are not available

• CONCEPT MV
  – Estimates emissions based on detailed link-based activity
    data (VMT and speed) from a Traffic Demand Model
  – Uses day-specific, grid cell-specific meteorological data
  – Highly resolved temporal and spatial variation of VMT and
    fleet mix


                                                                  5
               CONCEPT Overview
•   Consolidated Community Emissions Processing Tool
     – Open Source
     – Freely Available
     – Database Management System
     – Community Support & Enhancements
     – Balances Transparency/QA and Performance/Integration
       with GIS/Spatial Tools
     – Quality Assurance – Intermediate Tables Output
•   Includes all Emissions Source Categories
     – Point, Area, On/Off-Road Mobile, Biogenics
•   Performs same emissions processing as SMOKE
     – Temporal and Spatial Allocation, CEM Emissions
       Processing, Speciation, Growth & Control
•   Motor Vehicle (MV) Module Estimates Highly Detailed On-
    Road Vehicle Emissions

                                                              6
             CONCEPT MV

• Uses output from transportation demand
  models (TDM)
• Generates gridded, hourly link-level
  emissions by vehicle class
• Uses 8 MOBILE5 vehicle classes
• Detailed temporal resolution of traffic
  volume, speeds, and VMT mix
• Uses day/hour-specific gridded met data
• Stores many intermediate emissions
  tables for QA and data review
                                            7
    TDM Link Inputs to CONCEPT MV

• Endpoint coordinates and projection definition
• Volume and capacity
   – Typically provided for multi-hour periods for typical
     weekday, e.g. am peak, midday, pm peak, overnight
• Speeds
   – Generally free flow speeds are provided
   – Congested speed is calculated from free flow speed
     and volume/capacity ratio for each hour
• Roadway type
   – MOBILE6 has different emission factors by roadway
     type


                                                             8
    CONCEPT Temporal Allocation

• CONCEPT disaggregates link data
  (volume, capacities) for multi-hour periods
  into hourly volumes and capacities
• Requires hourly total volume profiles by
  roadway type, month, day of week
• Total volume temporal profiles are
  developed from analysis of local area
  automated traffic recorder (ATR) data
  (available from State DOTs)

                                                9
Denver Example Total Volume Temporal Profiles
                                                                    Denver Hourly Profiles for Urban Interstates                                                                                                                                       Denver Hourly Profiles for Urban Principal Arterials
                                                                                                                                                                                                                             0.1
                                     0.08

                                                                                                                                                        Jun
                                                                                                                                                        Jul
                                                                                                                                                                                                                                                                                                                                                Jun
                                                                                                                                                                                                                                                                                                                                                Jul
                                                                                                                                                                                                                         0.08

                                     0.06




                                                                                                                                                                                    Fraction of Total Traffic
Fraction of Total Traffic




                                                                                                                                                                                                                         0.06


                                     0.04


                                                                                                                                                                                                                         0.04




                                     0.02
                                                                                                                                                                                                                         0.02




                                       0                                                                                                                                                                                      0
                                             1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21                                                      1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21

                                                                                                              Hour                                                                                                                                                                                      Hour



                                                              Denver Day of Week Profiles for Urban Interstates                                                                                                                                   Denver Day of Week Profiles for Urban Principal Arterials
                                     0.18                                                                                                                                                                                    0.18



                                     0.16                                                                                                                                                                                    0.16



                                     0.14                                                                                                                                                                                    0.14
                                                                                                                                                                                                 Fraction of Total Traffic
         Fraction of Total Traffic




                                     0.12                                                                                                                                                                                    0.12

                                                                                                                                                       Jun                                                                                                                                                                                         Jun
                                       0.1                                                                                                                                                                                    0.1
                                                                                                                                                       Jul                                                                                                                                                                                         Jul


                                     0.08                                                                                                                                                                                    0.08



                                     0.06                                                                                                                                                                                    0.06



                                     0.04                                                                                                                                                                                    0.04



                                     0.02                                                                                                                                                                                    0.02



                                        0                                                                                                                                                                                          0
                                                      Sun                Mon                Tue                Wed                Thu                 Fri                Sat                                                                     Sun                Mon                Tue                Wed                Thu                 Fri               Sat
                                                                                                               Day                                                                                                                                                                                       Day


                                                                                                                                                                                                                                                                                                                                                                              10
CONCEPT Vehicle Mix Disaggregation
• TDM link volumes are generally total
  across all vehicle classes
• CONCEPT disaggregates total volume into
  eight MOBILE5 vehicle classes
• Requires hourly VMT mix profiles by
  roadway type, month, day of week, hour of
  day
• VMT mix temporal profiles are developed
  from analysis of local area vehicle
  classification recorder data
                                              11
Denver Example Vehicle Mix Temporal Profile
                  Denver Hourly Class Fractions (Sun-Sat) for Interstates, July
  0.6




  0.5




  0.4




  0.3




  0.2




  0.1




   0
        1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21 1   5   9 13 17 21

                      HDDV           HDGV             LDDT      LDDV           LDGT1           LDGT2           LDGV           MC

            HDDV VMT fraction is lower during am and pm peak traffic hours                                                                     12
      CONCEPT MV Steps in Estimation of
       On-Road Motor Vehicle Emissions

• Temporally allocate VMT to hours
• Adjust free flow speeds for congestion
• Spatially allocate links to grid cells
• Allocate total VMT to 8 MOBILE5 vehicle classes
• Run MOBILE6 with grid-specific meteorology
• Apply MOBILE6 emission factors using county
  inputs for fuel parameters and control programs
• Speciate emissions for air quality modeling



                                                    13
           Summary of CONCEPT vs. SMOKE Methods
               for On-Road Mobile Emissions

                                       SMOKE                                         CONCEPT MV
VMT                   County-level, by roadway type, by season        Link-level, hour-specific, from Transportation
                                                                      Demand Model (TDM), adjusted using
                                                                      hour/day/month temporal profiles from traffic
                                                                      counter data

Speeds                EPA national defaults by roadway type and       Link-specific speeds from TDM, adjusted for
                      vehicle class if data not submitted by States   congestion using hourly volume/capacity ratio


VMT mix               Uniform across all hours, days. Uses EPA        Detailed temporal profiles by hour/day/month
                      national defaults where data not submitted      from traffic classification monitoring data
                      by States

Temperature and       Calculates hourly average across all grid       Hour- and grid cell-specific temperatures
humidity              cells in each county

Temporal allocation   Emissions are temporally allocated using        Link-level hourly VMT estimated from link-
                      EPA default national-level profiles based on    specific inputs and hour/day/month temporal
                      activity data                                   profiles from local traffic counter data
Spatial allocation    County-level emissions are allocated to grid    Link-based emissions are allocated to grid cells
                      cells using Census TIGER files, smaller         based on link coordinates
                      roads not included




                                                                                                                         14
            Spatial Distribution of VMT for Grid Modeling is
                Very Different When Link VMT is Used




                         Max VMT                             Max VMT
                         = 301                               = 89




County-level VMT gridded to km     Link VMT gridded to 1km
Allocation based on Census TIGER   VMT distributed across more roads
roadway surrogates; creates VMT    – more detailed spatial coverage
“hot spots”
                                                                       15
Denver O3 SIP CONCEPT MV Application




                                       16
   Improved Denver Ozone Performance
using CONCEPT MV Link-Based Emissions

• Denver 8-hour ozone Early Action Compact (EAC)
  SIP (2002-2003) allocated county-level mobile
  emissions using Census TIGER roadways
  surrogates
  – Ozone suppressed in Denver metropolitan area every
    day of the episode leading to underprediction bias
• New Denver 8-hour ozone SIP modeling using
  CONCEPT MV to generate spatially and
  temporally highly resolved inventory does not
  exhibit such a large ozone hole
  – Better distinguishes weekend effect when high ozone
    occurs in metropolitan Denver


                                                          17
•   Example 8-h ozone model
    performance from Denver 8-
    h ozone EAC SIP modeling
•   Ozone “hole” occurs every
    day
•   Modeled ozone “hole” in
    metropolitan Denver of 55-60
    ppb ozone where some
    observed values > 70 ppb




                                   18
•   Example 8-h ozone
    model performance
    for new Denver SIP
    modeling using
    CONCEPT MV
    (Saturday)
•   Model now able to
    reproduce high
    ozone in
    metropolitan Denver




                    19
     CONCEPT MV Regional Application:
22 State and Local Networks in LADCO Domain




                                              20

								
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