Breathing Inequality: Does Darker Skin Mean Worse Air Quality?

What is it about?

Researchers concerned with environmental justice have found, often using data from the United States and Western Europe, that marginalized communities tend to face higher levels of environmental degradation. While one might expect these disparities to be even more pronounced in developing countries, measuring them presents two key challenges. The first problem is adequate measurement of pollution. In Colombia, for instance, the scarcity of land-based air quality monitors makes it difficult to assess pollution levels across most of the country. Second, racial and ethnic classifications (e.g., "Black vs. white") may not fully capture environmental inequality in regions where population divides are less clear-cut. Our research takes a different approach. Rather than relying on broad racial or ethnic labels, we examine whether skin tone influences pollution exposure. Using data from a large household survey and satellite-based pollution measurements, we find that skin tone plays a critical role in determining pollution exposure in Colombia. The differences in environmental outcomes across skin tones are striking. In 2010, people with lighter skin were exposed to higher levels of fine particulate matter (PM2.5). However, in the following years, pollution levels rose much faster for darker-skinned individuals. By 2016, the trend had fully reversed: darker-skinned Colombians were significantly more exposed to air pollution than their lighter-skinned counterparts. This pattern persists even when accounting for income, migration, and racial self-identification categories. One major driver of the shift is fires, which have disproportionately affected darker-skinned communities. Economic disparities and local community responses also play a role, but nearly one-third of this gap remains unexplained. In economics, the presence of an unexplained portion in racial or gender disparities is often interpreted as evidence of systemic discrimination, as it suggests that no measurable characteristic fully accounts for the observed gaps.

Featured Image

Photo by Malachi Brooks on Unsplash

Photo by Malachi Brooks on Unsplash

Why is it important?

Every year, outdoor air pollution generates three million premature deaths worldwide. In Colombia, pollution levels often surpass the limits recommended by the World Health Organization, posing severe health risks for the population. But not everyone breathes the same air. Our research reveals a shift in environmental disparities over time, placing a growing burden on darker-skinned individuals. By 2016, they were exposed to significantly higher levels of air pollution than their lighter-skinned counterparts. Satellite geolocation data points to fires as a key driver. Fires contribute heavily to air pollution and are increasingly concentrated in areas where darker-skinned communities live. With climate change fueling more frequent and intense fires, the health risks for vulnerable communities will only worsen unless targeted policies are put in place to address these disparities. Our findings suggrest that along with socioeconomic and geographic factors, fires explain two-thirds of the pollution gap. Strikingly, one-third remains unexplained, suggesting more research is needed to understand and fix structural inequalities.

Perspectives