Indicators Overview

Learn more about the indicators that make up CalEnviroScreen

What is an indicator?

An indicator is a measure of either environmental conditions, in the case of pollution burden indicators, or health and vulnerability factors for population characteristic indicators.

CalEnviroScreen indicators fall into four broad groups—exposures, environmental effects, sensitive populations, and socioeconomic factors.

  • Exposure indicators are based on measurements of different types of pollution that people may come into contact with.
  • Environmental effects indicators are based on the locations of toxic chemicals in or near communities.
  • Sensitive population indicators measure the number of people in a community who may be more severely affected by pollution because of their age or health.
  • Socioeconomic factor indicators are conditions that may increase people’s stress or make healthy living difficult and cause them to be more sensitive to pollution’s effects.

Each indicator is scored separately. Information on how they are scored and how the combined CalEnviroScreen score is produced can be found in the CalEnviroScreen 3.0 report.

How were the indicators selected? 

Each indicator is based on data from a federal, state, regional or local public agency that:

  • Provides a measure of pollution burden or population characteristics.
  • Is accurate and up-to-date.
  • Is available for the entire state.
  • Tells where the measurement was taken so that a score can be calculated for each census tract in California.

How are communities represented geographically?

  • Census tracts are used to represent the locations of communities across California.
  • Census tracts are geographic units that do not often change and are useful for combining, organizing, and mapping data.
  • CalEnviroScreen 3.0 uses census tract boundaries from the 2010 census.
  • Boundaries often follow visible features or landmarks, such as roads or rivers.
  • Census tracts usually contain between 1,200 and 8,000 people.
  • There are about 8,000 census tracts in California.

State Map of 2010 Census Tracts