Table 1.
List of variables.
| Variables | Definitions | Descriptions | Sources |
|---|---|---|---|
| Dependent Variable | |||
| Asthma | The emergency department visits for asthma per 10,000 people by census tract (patients’ residential location basis, 3-year averages between 2011 and 2013) | CalEnviroScreen 3.0 | |
| Tree Variables | |||
| TreeCov | Areas covered by trees | The percent of census tract areas covered by tree canopy (%) | Los Angeles Regional Imagery Acquisition Consortium |
| TreeClus | The size of tree patch | The median size of the clustered tree patch (square feet) | |
| TreeAgr | Nearest neighbor index (NNI) | The level of cluster (or dispersion) of tree patches | |
| Green/Open Space Variables | |||
| PrvtGrn | Private urban greenspace | The percent of census tract areas occupied by garden/landscape space of urban land use types including residential, commercial, office, and industrial (%) | Los Angeles Regional Imagery Acquisition Consortium (LARIAC) |
| GrnRec | Greenspace in recreational areas | The percent of census tract areas occupied by greenspace, which is largely accessible by the public, including parks and recreational areas (%) | |
| SemiGrn | Semi-public greenspace | The percent of census tract areas occupied by greenspace, which is not accessible by the public, including golf courses, educational facilities, and cemeteries, as well as agricultural lands (%) | |
| Socio-Demographic Variables | |||
| PovRt | Poverty rate | The percent of households whose income in the past 12 months was below the poverty level (%) | The American Community Survey (2016; 5-year estimates) |
| EduAtn | Education attainment | The percent of population with high school degree or lower (%) | |
| EtnGrp | Ethnical background | The percent of the African American population (%) | |
| ChldPop | Children population | The percent of children population whose age is 10 or under (%) | |
| SnrPop | Elderly population | The percent of the elderly population whose age is 65 or above (%) | |
| Air Quality Variables | |||
| PM2.5 | Particulate matter 2.5 | The average of particulate matter 2.5 concentration from the years 2011 to 2013 | CalEnviroScreen 3.0 |
| Ozone | Level of ozone | The average daily maximum ozone concentration for the years 2011 to 2013 | |