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Toxic Releases

Variable Definitions:
Toxic Releases Percentile: The percentile of a given area’s average annual exposure to EPA-flagged toxic releases from industrial plants across LA County

Methodology Note
The original CalEnviroScreen dataset provides percentiles across all California census tract. However, these percentiles are recalculated exclusively within Los Angeles County census tracts to fit NDSC’s geography.

For more information on the California Office of Environmental Health Hazard Assessment’s methodology, visit the CalEnviroScreen homepage.

California Office of Environmental Health Hazard Assessment – CalEnviroScreen 2.0 (2014), CalEnviroScreen 3.0 (2017), CalEnviroScreen 4.0 (2021)

Years Available:

CalEnviroScreen 2.0: 

Data collected from 2009-2011 and published in 2014

CalEnviroScreen 3.0: 

Data collected from 2012-2014 and published in 2017

CalEnviroScreen 4.0: 

Data collected from 2017-2019 and published in 2021

Why are these variables important to measure?

The United States’ Environmental Protection Agency and Mexico’s Registry of Emissions and Pollutant Transfer track emissions of 329 toxic chemicals from industrial facilities. The Toxic Releases percentile accounts for wind patterns, weather, geography, and the toxicity of each chemical to determine the risk posed to residents of different communities. The higher the percentile, the higher the likelihood of residents experiencing negative health impacts caused by the toxic chemicals. This percentile can be higher either through a greater likelihood of exposure or through poorer expected health outcomes as a result of exposure to particular chemicals. 
Analyzing the risk from these chemicals is particularly important for public health, as the tracked chemicals have been linked to brain cancer in children, higher infant mortality rates, low birth weight, cardiovascular disease, and higher overall mortality rates. Further, the dangers of toxic releases contribute to environmental injustice. Multiple studies have shown that low-income areas and people of color are more likely to be affected by toxic releases. Racial and ethnic disparities are even stronger in neighborhoods with median incomes below $25,000. 


August, Laura, et al. “CalEnviroScreen 4.0.” Oehha.ca.gov, Oct. 2021, https://oehha.ca.gov/calenviroscreen/report/calenviroscreen-40.
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Hendryx M, Fedorko E (2011). The relationship between toxics release inventory discharges and mortality rates in rural and urban areas of the United States. The Journal of Rural Health 27(4):358- 66. 
Morello-Frosch R, Pastor M, Jr., Porras C, Sadd J (2002). Environmental justice and regional inequality in southern California: implications for future research. Environ Health Perspect 110 Suppl 2:149-54.
Sadd JL, Pastor Jr M, Boer JT, Snyder LD (1999). “Every Breath You Take…”: The Demographics of Toxic Air Releases in Southern California. Economic Development Quarterly 13(2):107-23. 
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