Goods Movement Map: Methods and Sources
We used data from South Coast Air Quality Management District, obtained by the People's Collective for Environmental Justice, to map warehouses throughout Los Angeles, Orange County, West San Bernardino and West Riverside. This data set contained warehouses over 100,000 square feet, as these facilities are subject to the agency’s Indirect Source Rule, which aims to reduce emissions from diesel trucks and tractor-trailers that run to and from warehouses.
Pollution percentile data comes from the California Office of Environmental Health Hazard (OEHHA). OEHHA calculates averages for ozone concentration and PM 2.5 concentration and yearly total Diesel PM emissions for every census tract in the state and ranks them to calculate a statewide percentile for each tract. In the sidebar on our map, we used these census tract percentiles to calculate the median percentiles for each pollution type for each city. The goal was to best represent cities with outlying census tracts.
Sources
California rail network, airport runways and highways from California Department of Transportation, 2021; City boundaries from California Department of Technology, 2019; County boundaries from California Department of Forestry and Fire Protection, 2021; Warehouse addresses from South Coast Air Quality Management District, 2020 (via People’s Collective for Environmental Justice); Air pollution percentile data from California Office of Environmental Health Hazard, 2021; Median household income and racial demographics from US. Census Bureau, 2020
