Development of Spatial Allocation Factors for the SCOS97 Domain Prepared by: Tami H. Funk Lyle R. Chinkin Sonoma 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

2 Overview Introduction Acquisition of surrogate data New approach to developing surrogates Development of spatial allocation factors Display and discussion of gridded spatial allocation factors

3 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

4 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

5 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

6 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

7 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

8 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

9 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

10 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)

11 Polygon Point Line Grid Overlay area/grid cell number/grid cell length/grid cell

12 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 = % of the county total population resides in grid cell (x) X

13 Spatial Allocation Factor Population

14 Spatial Allocation Factor Population

15 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 No. structures 1997) Assuming 30% expenditure on repair and maintenance (U.S. Census Bureau, 1998) (Existing Structures)(New Structures)

16 Calculated Surrogates Residential Construction (1997)

17 Calculated Surrogates Residential Construction (2020)

18 Calculated Surrogates Residential Construction 1997 and 2020

19 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.

20 Summary New methodologies were used to better characterize “real-world” spatial emissions patterns and densities. All surrogates can be viewed at: