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Air Quality

Variable Definitions:
PM 2.5 Concentration: The average annual concentration of fine particulate matter (PM2.5) in the air, measured in micrograms per cubic meter (µg/m³) of air

Air Quality Percentile: The percentile of a given area’s PM2.5 concentration, compared to the rest of 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?

PM2.5 Concentration

PM2.5, also known as fine particle matter, refers to tiny particles in the air that are 2.5 micrometers or less in diameter, allowing them to penetrate the lungs. Particle matter can include a mixture of organical chemicals, wood, dust, soot, and metals; and can be released into the air from cars and trucks, factories, and wood burning and fires. Because PM2.5 can penetrate the lungs and bloodstream, it may cause many adverse health effects including lung and heart disease. Children, the elderly, and persons suffering from cardiopulmonary disease, asthma, and chronic illness are the most susceptible to health complications from PM2.5. As such, it is important for communities and policymakers to understand air quality levels in order to anticipate adverse health outcomes as a result of air pollution, which can frequently be a direct result of local infrastructure and other structural decisions. 

The California Air Resources Board measures PM2.5 concentrations in the air from air monitoring stations around the state of California. The U.S. Environmental Protection Agency (EPA) has set a standard of 12 micrograms of PM2.5 per cubic meter of air (12 µg/m3) as an acceptable average annual concentration.

Faust, John et al. “Update to the California Communities Environmental Health Screening Tool: CalEnviroScreen 3.0.” Office of Environmental Health Hazard Assessment & California Environmental Protection Agency, January 2017. Link

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