Development of Spatial Allocation Factors for the SCOS97 Domain

Prepared by:Tami H. Funk

Lyle R. ChinkinSonoma Technology, Inc.

Petaluma, CA

Under contract to:California Air Resources Board

Paul Allen, Project Manager

SCOS97-NARSTO DATA ANALYSIS CONFERENCE February 14, 2001

STI-2053

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Overview

• Introduction

• Acquisition of surrogate data

• New approach to developing surrogates

• Development of spatial allocation factors

• Display and discussion of gridded spatial allocation factors

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Introduction

• Spatial allocation factors are used to geographically distribute county total emissions over a gridded domain.

• Spatial allocation factors are developed using spatial surrogate data:

– Demographic and socioeconomic data• population, housing, employment

– Land cover and land use data• lakes, railroads, roadways, agriculture

– Facility location data• dry cleaners, gas stations, airports, military bases

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Acquisition of Surrogate Data (1 of 2)

• Demographic and socioeconomic data

– Demographic and socioeconomic data from local transportation planning agencies and Caltrans for 1997, 2005, 2010, and 2020

• Land cover and land use data

– USGS, ESRI/MapInfo TIGER files (e.g., railroads, lakes)

– Road networks from DTIM inputs

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Acquisition of Surrogate Data (2 of 2)

• Facility location data

– Area source facility locations from the Electronic Yellow Pages

– Oil well locations from California Department of Oil and Gas.

– Bulk plant locations from CEIDARS.

• New calculated surrogates

– Based on demographic and socioeconomic data

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List of Spatial Allocation Factors (1 of 4)

Demographic and Socioeconomic Surrogates• Total population

• Total employment

• Non-retail employment

• Other employment

• Retail employment

• Retail & other employment

• Basic employment

• Total housing

• Multiple-dwelling units and retail employment

• Group quarters/retail employment

• Proportional to construction, population, and employment densities

• Proportional to housing density and total employment

• Single-dwelling units

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List of Spatial Allocation Factors (2 of 4)

Land Cover and Land Use Surrogates• Agricultural land cover

• Agricultural land cover - cropland

• Agricultural land cover - feedlot

• Coastline distributions

• National forest >5000 feet

• Rural land cover - forest

• Rural land cover - range land

• Rural land cover

• Roadway density

• VMT - collectors

• VMT - freeways

• VMT - local streets

• VMT - major streets

• VMT

• Railroad length

• Rail yards

• Lakes, reservoirs, and coastline

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List of Spatial Allocation Factors (3 of 4)

Facility Location Surrogates• Commercial airports

• Non-commercial airports

• Military bases

• Oil wells

• Harbors

• Autobody & repair shops

• Restaurants & bakeries

• Dry cleaners

• Golf courses

• Schools, parks, and hospitals

• Service stations

• Wineries

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List of Spatial Allocation Factors (4 of 4)

Calculated Surrogates• Total housing and total employment/area per person

• Proportional to % maintenance construction and housing densities

• Proportional to % maintenance construction and non-retail densities

• Proportional to % maintenance construction and retail densities

• Proportional to % maintenance construction and basic employment density

• Proportional to % maintenance construction and residential population density

• Proportional to % maintenance construction and other employment density

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Development of Spatial Allocation Factors

• Use Geographical Information Software (GIS) to spatially disaggregate geographical data into 2-km grid cells using overlay functions.

• Calculate the spatial allocation factor (SAF):

SAF = (grid cell value / county total)

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Polygon

Point

Line

Grid Overlay

area/grid cell

number/grid cell

length/grid cell

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Example Calculation: Population

Pop. of TAZ = 5,000

Total County Pop. = 50,000

Pop. of Grid Cell (x) = 500

SAF = Population of Grid Cell / Population of County = 500 / 50,000 = 0.01 1% of the county total population resides in grid cell (x)

X

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Spatial Allocation Factor - 1997 Population

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Spatial Allocation Factor - 2020 Population

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New Approach - Calculated Surrogates

• Use demographic and socioeconomic data to develop calculated surrogates.

Example: Residential construction emissions

1997

TAZ

Existing Structures

2020

New Structures

Surrogate = [(No. structures 1997)*(0.30)] + (No. structures 2020 - No. structures 1997)

Assuming 30% expenditure on repair and maintenance(U.S. Census Bureau, 1998)

(Existing Structures) (New Structures)

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Calculated SurrogatesResidential Construction (1997)

Lancaster

Palmdale

Santa Clarita

Glendora

Los Angeles

Long Beach

Los Angeles - 19970.00001 - 0.0000120.000012 - 0.000360.00036 - 0.000870.00087 - 0.00205

City BoundariesCounty Boundaries

30 0 30 60 Miles

N

EW

S

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Calculated SurrogatesResidential Construction (2020)

Lancaster

Palmdale

Santa Clarita

Glendora

Los Angeles

Long Beach

Los Angeles - 20200.00001 - 0.0000120.000012 - 0.000360.00036 - 0.000870.00087 - 0.00205

City BoundariesCounty Boundaries

30 0 30 60 Miles

N

EW

S

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Calculated SurrogatesResidential Construction 1997 and 2020

Lancaster

Palmdale

Santa Clarita

Glendora

Los Angeles

Long Beach

Los Angeles - 20200.00001 - 0.0000120.000012 - 0.000360.00036 - 0.000870.00087 - 0.00205

Los Angeles - 19970.00001 - 0.0000120.000012 - 0.000360.00036 - 0.000870.00087 - 0.00205

City BoundariesCounty Boundaries

30 0 30 60 Miles

N

EW

S

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Summary

• Approximately 50 different gridded spatial allocation factors were developed for 1997, 2005, 2010, and 2020 at a 2-km grid resolution.

• New and improved geographical data are rapidly becoming available with the widespread use of GIS technology.

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Summary

• New methodologies were used to better characterize “real-world” spatial emissions patterns and densities.

• All surrogates can be viewed at: http://www.arb.ca.gov/eos/scos97/gei.html