Table 2.
Population size and baseline health outcome and exposure estimates used to evaluate the burden of asthma due to air pollution in LAC in 2007.
| Variable | Value | Description (reference) | ||
|---|---|---|---|---|
| Target population | ||||
| Total population of children, age 0–17 years | 2,549,722 | LAC, ages 0–17 population, 2007 (U.S. Census Bureau 2011) | ||
| Background level | ||||
| Asthma prevalence in children | 0.1257 | CHS (McConnell et al. 2006) | ||
| Fraction reporting bronchitis symptoms (per year) | 0.387 | CHS (McConnell et al. 2003) | ||
| Fraction reporting doctor visits for asthma (per year) | 0.751 | CHS, personal communication, McConnell R, 2011a | ||
| No. of yearly emergency department visits for asthma (ICD-9: 493) | 18,658 | California breathing, Los Angeles County, 2007, personal communication, Milet M, 2011, based on California Office of Statewide Health Planning and Development, 2007 | ||
| No. of yearly hospital admissions for asthma per year (ICD-9: 493) | 3,131 | California breathing, Los Angeles County, 2007, personal communication, Milet M, 2007, based on California Office of Statewide Health Planning and Development | ||
| Average daily school absence rate for respiratory illness among children with asthma | 0.0158 | CHS (Gilliland et al. 2001) | ||
| Population exposure (baseline)b | ||||
| Proximity (75 m) to major roads (%) | 17.8 | Percent of LAC 2009 parcel population living within 75 m of nearest major roadc | ||
| Annual dispersion-modeled near-roadway NOx population-weighted concentration (ppb) | 2.56 | CALINE4, 2007, functional arterial classification code FCC3 (state highways) | ||
| Annual NO2 population-weighted concentration (ppb) | 23.3 | 2007 U.S. EPA Air Quality System and CHS | ||
| 8-hr maximum O3 population-weighted concentration (ppb) | 39.3 | 2007 U.S. EPA Air Quality System and CHS | ||
| Abbreviations: CHS, Children Health Study; EPA, Environmental Protection Agency; ICD-9, International Classification of Diseases, 9th Revision (World Health Organization 1975). aFrom the CHS question “Ever been to doctor for wheezing?” among those that have ever had wheezing. This question was not restricted to the previous year. bRepresented by block group population-weighted concentration except for traffic proximity, which was represented by the average centroid parcel distance to busy roads. cDefined as functional road class (FRC) 01, FRC03, or FRC04 from TeleAtlas MultiNet roads network. | ||||