People of Color and Low-Income Communities in D.C. are Disproportionately Affected by Air Pollution

According to a new study, individuals of color and those with lower household income and educational attainment bear a disproportionate and inequitable share of the death and health burdens associated with air pollution in Washington, D.C.

Air pollution is the top environmental health risk factor, and recent efforts in the D.C. region have significantly reduced levels of fine particulate matter, or PM2.5, in the air. Air pollution is any chemical, physical, or biological factor that contaminates the indoor or outdoor environment and alters the natural properties of the atmosphere.

Air pollution is commonly caused by household combustion devices, motor vehicles, industrial operations, and forest fires. Particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide are all serious public health concerns. Air pollution, both outside and inside, is a leading cause of respiratory and other ailments, as well as a significant source of morbidity and mortality.

While PM2.5-related mortality and health burdens in the D.C. area halved between 2000 and 2018, inequities and spatial segregation in health consequences persist, according to the latest study. Air pollution is a huge hazard to health and the environment, from haze hanging over cities to smoke within the home.

People residing inwards five, seven, and eight in the District’s east and southeast districts are the most affected by PM2.5 air pollution. In comparison to northwest neighborhoods, researchers discovered that baseline disease rates for chronic obstructive pulmonary disease, lung cancer, and stroke are five times higher in southeastwards, up to nine times higher for all-cause mortality and coronary heart disease, and over 30 times higher for asthma emergency department visits.

Residents in these hardest-hit areas have 10% lower education and employment rates, 10% more people living in poverty, a median family income of $61,000 less than the rest of the city, and a life expectancy of around 10 years less than the rest of the city.

The top ten impacted communities have a 54 percent higher Black population and a 44 percent lower white population. This work emphasizes the value of detailed health and air quality data, and the authors believe that it will help guide future decisions to address environmental health inequities and serve as a model for air pollution health evaluations in other areas.

Example of air pollution

The findings were published in GeoHealth, an AGU publication dedicated to the interaction of human and planetary health in the pursuit of a sustainable future.

“We knew that concentrations were higher in the east of D.C., and we knew that people were getting sicker in the east, but I don’t know if we were able to tell before that they were getting sicker because of pollution,” said lead study-author Maria Castillo, a graduate student in City Planning at MIT.

“Now that we apply all these calculations, all these concentration-response functions, we’re able to tell people, ‘Air pollution is the cause of some of the morbidity outcomes that you are seeing in this area.’ Making that connection between pollution and health impact outcomes I think is very powerful.”

We knew that concentrations were higher in the east of D.C., and we knew that people were getting sicker in the east, but I don’t know if we were able to tell before that they were getting sicker because of pollution.

Maria Castillo

According to research co-author Susan Anenberg, an environmental health expert at George Washington University, unequal health outcomes can be traced to two key causes. For starters, air pollution levels vary by neighborhood. Highways and bus stations, for example, can send a lot of pollutants into a neighborhood, which is bad for the residents.

Independent of air pollution, the second driver is an individual’s health situation. Lower life expectancy and higher rates of asthma, health endpoints, and emergency visits are evident in D.C.’s southeastern communities, with lower life expectancy and higher rates of asthma, health endpoints, and emergency visits.

When inhabitants are exposed to pollutants, these underlying health concerns can make them more sensitive, resulting in increased levels of poor air pollutant-related health outcomes.

“You can’t think about air pollution in isolation. When it comes to health risks and environmental justice, we have to think of the total lived experiences that people are having,” Anenberg said.

“If folks don’t have adequate access to quality healthcare, that means when they are exposed and have health effects as a result of that air pollution exposure, they may have worse outcomes because they’re not getting the treatment that they need.”

Focusing on fine-resolution data

To analyze the effects of air pollution in the nation’s capital, researchers used novel exposure assessment technologies. Castillo and her co-authors used pollution estimate that integrated data from on-the-ground air monitors with satellite data to capture some of the regional variances in pollution levels across the city in order to assess air pollution.

They looked at data from the Centers for Illness Control as well as administrative disease rate statistics from the District of Columbia Department of Health, which gave more detailed health data on a local scale.

Researchers hope to use D.C.’s unique position as a city with thought leaders in environmental justice and policy, as well as more granular health data than other states, to develop scalable solutions that can be applied to other areas. They hope that this study might be used as a model for developing targeted policies rather than just reducing total air pollution.

“I think one of the strengths of the study is that it really laid out a road map that could be done other places,” said Jonathan Levy, an expert in Environmental Health at Boston University who was not involved in the study. “The air quality data they used, that’s universally available every place across the U.S. … there are real opportunities to take this kind of approach and do it much more widely.”

According to Kelly Crawford, study co-author and Associate Director of the D.C. Department of Energy and Environment, this study could be used as a model to ensure policymaking is driven by health data that accurately reflects racial diversity and health outcome disparity in populations, which has not always been the case.

“Doing further studies that at the very least acknowledge the disparity or lack of diversity in data sets… I think that is the role of government and research in addressing racism,” Crawford said.