Ethnoracial Disparities in Nitrogen Dioxide Pollution in the United States: Comparing Data Sets from Satellites, Models, and Monitors
This study has significant implications for addressing environmental justice issues related to NO₂ pollution, advocating for better monitoring and data integration, informing targeted interventions, and influencing policy to protect and improve the health of ethnoracial minorities disproportionately affected by air pollution.
College of Health researcher(s)
College unit(s)
Highlights
Key Findings
Ethnoracial Disparities
The study found that in 2019, Black, Hispanic, Asian, and multiracial populations were exposed to NO₂ levels 15-50% higher than the national average. In contrast, non-Hispanic White populations experienced exposure levels 5-15% lower than the national average.
Limitations of In Situ Monitors
Despite being a traditional method for measuring NO₂ levels, in situ monitors have limited geographical coverage, leaving 66% of urban areas unmonitored. The study also notes that these monitors tend to be located in areas with demographic compositions similar to the overall urban or rural demographics, but with a slight tendency to be placed in areas with a higher percentage of ethnoracial minorities.
Advantages of Integrating Multiple Data Sets
By integrating data from various sources, the study was able to provide a more complete and high-resolution picture of NO₂ pollution. This approach allows for a better understanding of spatial variations in pollution levels and the ability to track exposure and inequality more effectively.
Environmental Justice Concerns
The findings highlight significant environmental justice issues, with the highest NO₂ levels found in marginalized, racialized, and minoritized communities. The study points to historical practices such as redlining and racist zoning as root causes of these disparities.
Abstract
In the United States (U.S.), studies on nitrogen dioxide (NO2) trends and pollution-attributable health effects have historically used measurements from in situ monitors, which have limited geographical coverage and leave 66% of urban areas unmonitored. Novel tools, including remotely sensed NO2 measurements and estimates of NO2 estimates from land-use regression and photochemical models, can aid in assessing NO2 exposure gradients, leveraging their complete spatial coverage. Using these data sets, we find that Black, Hispanic, Asian, and multiracial populations experience NO2 levels 15–50% higher than the national average in 2019, whereas the non-Hispanic White population is consistently exposed to levels that are 5–15% lower than the national average. By contrast, the in situ monitoring network indicates more moderate ethnoracial NO2 disparities and different rankings of the least- to most-exposed ethnoracial population subgroup. Validating these spatially complete data sets against in situ observations reveals similar performance, indicating that all these data sets can be used to understand spatial variations in NO2. Integrating in situ monitoring, satellite data, statistical models, and photochemical models can provide a semiobservational record, complete geospatial coverage, and increasingly high spatial resolution, enhancing future efforts to characterize, map, and track exposure and inequality for highly spatially heterogeneous pollutants like NO2.