CalEnviroScreen 4.0 and Race/Ethnicity Analysis

CalEnviroScreen scores represent a combined measure of pollution and the potential vulnerability of a population to the effects of pollution. Like the previous versions, CalEnviroScreen 4.0 does not include indicators of race/ethnicity or age. However, the distribution of the CalEnviroScreen 4.0 cumulative impact scores by race or ethnicity is important. This information can be used to better understand issues related to environmental justice and racial equity in California. CalEPAs racial equity team has released a  StoryMap  using CalEnviroScreen 3.0 data that examines the connection between racist land use practices of the 1930s and the persistence of environmental injustice. The CalEPA StoryMap, along with this analysis, are examples of information that can be used to better understand issues related to environmental justice and racial equity in California.

This StoryMap, along with a report, provides an analysis of the relationship between CalEnviroScreen 4.0 results and race/ethnicity and shows clear disparities with respect to the racial makeup of the communities with the highest pollution burdens and vulnerabilities. People of color, especially Latino and Black people, disproportionately reside in highly impacted communities in California. The results using CalEnviroScreen 4.0 scores are consistent with earlier versions of the tool, and reflect racial disparities, with the highest percentages of people of color living in the most highly impacted communities. OEHHA plans to release a more extensive analysis of race/ethnicity and age using the CalEnviroScreen 4.0 results in the future.

We evaluated potential associations between race/ethnicity and CalEnviroScreen 4.0 scores released in February 2021. We used race/ethnicity data from the 2015-2019 American Community Survey of the census and the results from CalEnviroScreen 4.0 available here for public comment. In preparing this report, OEHHA staff used the same methods as our previous analysis of  CalEnviroScreen 3.0 scores and race/ethnicity .

Figure 1 the shows the range of CalEnviroScreen 4.0 scores as represented by percentiles experienced by Californians of different races and ethnicities. We assigned all Californians a CalEnviroScreen 4.0 percentile score based on the census tract they live in and then grouped them by race/ethnicity. The dark horizontal lines in each box and the numbers above them indicate the median (50th percentile) CalEnviroScreen score for each group. The shaded boxes correspond to the “Interquartile Range” (IQR), or the range of values between the 25th to 75th percentile. The dashed vertical lines show the range of the extreme values experienced by the groups. 

The dashed vertical lines show that all racial/ethnic groups have some members living in communities with the lowest and highest CalEnviroScreen scores. However, the chart also shows that the average CalEnviroScreen percentile score is lowest for whites and much higher for Latinos, Blacks and Pacific Islanders than for other groups. This indicates that Latinos, Blacks and Pacific Islanders tend to live in communities with higher pollution burdens and vulnerabilities than the other racial/ethnic groups analyzed.

Figure 2 below shows the percentage of people of color and white populations living in the least and most impacted communities identified in CalEnviroScreen 4.0. Census tracts across the state were ranked into ten categories (deciles) with equal numbers of census tracts in each. The circle chart on the left represents the least impacted 10% of census tracts (first decile) while the circle chart on the right represents the most impacted 10% of census tracts (10th decile) by percentage people of color and white. These figures demonstrate significant differences in the in racial makeup between the least and most impacted neighborhoods.

Figure 3 examines in greater detail how communities grouped by their CalEnviroScreen score vary by race/ethnicity. The top-most horizontal bar (first decile) shows the race/ethnic makeup of the least impacted census tracts (1-10th percentile of CES score), while 10th decile toward the bottom of the chart shows the race/ethnic makeup of the most impacted census tracts (91-100th percentile). The overall demographic makeup of the California population using the 2015-2019 ACS data is shown at the very bottom of the chart. (Note: Due to their small numbers relative to other racial/ethnic groups, Native Americans and Pacific Islanders were grouped into the “Other” category in this figure.)

If impacts were distributed equally across the California population, the proportion of each racial/ethnic group in each decile would be equal to its overall proportion in the California population. That is, an even distribution of pollution burden and population vulnerability across racial and ethnic groups would mean that all the bars would resemble the bottom bar in Figure 3. However, it is clear from the chart that this is not the case. Instead, Latinos and African Americans disproportionately reside in highly impacted communities while other groups tend to reside disproportionately in less impacted communities. Previous versions of CalEnviroScreen data and race/ethnicity data would yield similar findings.

Another way to visualize disproportionate impacts by race/ethnicity is through analyzing CalEnviroScreen scores with information on race/ethnicity by census tract. The most prevalent race or ethnicity for each census tract was determined by the race/ethnicity with the highest population in each census tract as reported in the  2015-2019 American Community Survey .

Figure 4 shows the breakdown of the most prevalent race within the 10% most impacted census tracts for four racial/ethnic groups. Similar to the findings shown in Figure 3, Latinos are over-represented in the 10% most impacted census tracts, representing 23% of the group’s total tracts (in which Latinos are most prevalent). Although only 21 census tracts that are predominantly Black are in the 10% most impacted census tracts, this represents 18% of the group’s total tracts.