An evident trend emerges when examining the racial demographics of the 10 California counties with the highest and lowest AQI values.

Counties with lower AQI levels, indicating cleaner air and shown on the rightmost bar graph, tend to have predominantly white populations. Notably, 7 out of 10 of these counties have populations that are at least 70% white.

In contrast, counties with higher AQI levels, signifying poorer air quality and shown on the leftmost bar graph, have a greater presence of ethnic minorities, primarily Hispanic and Black populations. Strikingly, all 10 of the California counties with the highest AQI values have white populations below 45%, a stark difference from those with cleaner air.

A similar pattern emerges when examining the racial demographics of the 10 counties with the lowest PM2.5 levels, another indicator of having cleaner air. In these counties, shown on the rightmost bar graph, 7 out of 10 have populations that are more than 60% white.

Conversely, in counties with the highest PM2.5 levels, indicating prolonged exposure to fine particulate pollution and shown on the leftmost bar graph, there is significantly greater racial diversity. These areas have higher representations of Hispanic, Native Hawaiian and Pacific Islander, Black, and Asian populations. Notably, only 2 out of 10 of these counties have populations that are more than 60% white.

Overall, this data suggests a relationship between air quality and racial demographics in California counties. The trend indicates that counties with cleaner air (lower AQI and PM2.5 values) tend to have predominantly white populations, while counties with poorer air quality (higher AQI and PM2.5 values) have a greater proportion of minority populations, such as Hispanic and Black.

A possible explanation for this relationship could come from the fact that, historically, marginalized populations have been more likely to live in areas with higher pollution levels due to systemic factors such as redlining, industrial zoning, and economic barriers. These communities typically have less political influence to advocate for stricter environmental regulations, cleaner infrastructure, and pollution control measures.

These findings are extremely important and can be connected to other valuable studies. In Allegheny County, Pennsylvania, from 2010 to 2018, it was found that AQI was “associated with asthma exacerbations among children in Allegheny County… driven primarily by PM2.5, with Black and younger children particularly affected” (Rosser, 2022). This study highlights that Black children are especially vulnerable to the health effects of poor air quality. Our data shows that California’s Black populations are more concentrated in areas with the worst air quality. Given the established link between air pollution and respiratory illness, these disparities could lead to severe and disproportionate health consequences for these communities.