Environment Drives Respiratory Health Disparities

In 2016, Brady Scott was in his parents’ home in Garrett, Kentucky, scrolling his Facebook feed when a post from a local newspaper caught his attention. “The article said that if you grew up in the region I grew up in, compared to the richer Central Kentucky region, the life expectancy differed by about 9 years,” he recalled.

The respiratory therapist, then a PhD student at Rush University, Chicago, was struck and began “Googling” to find out why this was the case. Initially, he thought diabetes, smoking, and economic distress — all prevalent problems in the area — were the culprits. However, he soon found that respiratory disease was particularly common in his region.

Now a professor and program director of the Respiratory Care Program at Rush University, Scott has spent several years trying to understand why people in certain regions experience respiratory illness at higher rates than in other places.

The Environment as a Determinant of Health

When Scott began his PhD, the prevalence of asthma in Southeast Kentucky, part of the Appalachian region, was already well-documented. He focused his research on uncontrolled asthma and the triggers that drove asthma exacerbations.

Housing quality emerged as an important factor. He found that exposure to mold, mildew, dust mites, pests, and rodents increased the risk for asthma and exacerbated existing cases. Lower-income families, more likely to live in poor-quality housing, were significantly affected, even in single-family homes.

Wanda Phipatanakul, MD, MS, director of the Division of Immunology Research Center at Boston Children’s Hospital and S. Jean Emans professor of Pediatrics at Harvard Medical School, Boston, has found similar results in urban environments. She said cockroach and mouse allergen exposure is disproportionately prevalent in urban, low-income neighborhoods. These exposures, closely tied to housing conditions, contribute to worse asthma and respiratory problems, particularly in children.

Scott and Phipatanakul agreed that the environment surrounding people’s homes can also exacerbate respiratory disease.

Rural areas present unique risks, such as agricultural activities that release pesticides and other particulates into the air, said Scott. In mountainous areas like Appalachia, mining operations are another significant contributor. For example, blasting mountains with dynamite creates large clouds of dust and pollutants that settle in valleys. Coal-hauling roads contribute to air quality issues, too. And houses near these roads may be exposed to increased levels of particulate matter, he said.

In the city, Phipatanakul has found that historical practices like redlining have systematically denied certain neighborhoods access to resources and investment, leaving a legacy of poor infrastructure, limited resources, and higher exposure to environmental risks. Today, these areas have more highways and fewer green spaces and are disproportionately linked with a higher incidence of respiratory illnesses.

The findings of both Scott and Phipatanakul underscore a critical bottom line: Health disparities are deeply influenced by environmental factors, which are themselves shaped by socioeconomic conditions and historical inequities. Poor housing quality, exposure to allergens, and proximity to environmental hazards disproportionately affect underserved and minority communities, whether in rural or urban settings.

The Role of Green Spaces in Improving Respiratory Health

Restoring and increasing tree cover and green spaces in urban areas can significantly improve respiratory health by addressing environmental challenges and reducing triggers for respiratory issues. Areas with greater greenness tend to have lower levels of pollutants and fewer environmental infestations, such as mice and cockroaches, explained Phipatanakul. Her research highlights that schools in greener areas have fewer airborne pollutants and particles than those in more urbanized, less green areas, which are usually in poorer suburbs.

Trees absorb pollutants such as particulate matter and sulfur dioxide through dry deposition and stomatal uptake, improving air quality. “The question is whether we can use trees as a public health tool, and this is being done in many cities,” said Alessandro Marcon, PhD, a professor of epidemiology and medical statistics at the University of Verona, Verona, Italy, while speaking at the European Respiratory Society conference held in Vienna last September.

A US analysis showed that existing natural vegetation, such as forests and grasslands, absorbs a large portion of emissions. By restoring land cover, pollution from harmful substances like sulfur dioxide and particulate matter could be reduced by about 30%. This approach is often more cost-effective than technological solutions for managing emissions.

Moreover, tree cover contributes to a healthier air microbiome. Research indicates that urban forest areas have lower pathogenic bacteria and fungi concentrations than nearby urban zones.

Another major advantage is the mitigation of the urban heat island effect. A study conducted in Paris found that municipalities with higher tree coverage experienced 20%-30% lower heat-related mortality than those with less greenery. Increasing tree coverage to 30% could reduce up to 40% of excess mortality associated with urban heat islands. Trees achieve this by providing shade and facilitating evapotranspiration, which cools the surrounding air.

Urban environments, unsurprisingly, often have higher levels of air pollution due to increased traffic and industrial activity. However, despite appearing greener, rural environments may harbor less obvious but significant sources of air pollution. “I live in an urban environment now, but I grew up in a rural environment,” Scott said. “Each has its own issues that affect air quality and health.”

Scott, Phipatanakul, and Marcon reported no relevant financial relationships.

Manuela Callari is a freelance science journalist specializing in human and planetary health. Her words have been published in The Medical Republic, Rare Disease Advisor, The Guardian, MIT Technology Review, and others.