Nitrogen Dioxide Air Pollution Plays Significant Role In Childhood Asthma: Study

Despite declining levels of nitrogen dioxide around the world due to the pandemic, levels remain high in urban areas where the poor and people of color live.

More than two million children have asthma that may be linked to traffic-related nitrogen dioxide air pollution, according to the findings of new research.

A study published this month in the medical journal The Lancet: Planetary Health indicates that more than two-thirds of new pediatric asthma cases appear to be associated with the air pollutant nitrogen dioxide in urban areas throughout the world.

Researchers from George Washington University evaluated rates of childhood asthma cases and the global surface nitrogen dioxide concentrations from air pollution, using data from the NASA Goddard Space Flight Center and data from the Global Burden of Disease study for 1990-2019 at a 1 km resolution. They estimated asthma incidence trends in more than 13,000 cities from 2000 to 2019.

Scaling the data set for 2010 to 2012, from a land use regression model based on more than 5,000 nitrogen dioxide monitors in 58 countries, researchers estimated 1.85 million new pediatric asthma cases around the globe were attributable to nitrogen dioxide in 2019, two-thirds of which occurred in urban areas. Overall, urban areas had two to four times higher concentrations of nitrogen dioxide compared to rural areas.

During the first lockdown of the COVID-19 pandemic, concentrations of nitrogen dioxide in the US decreased in urban areas but remained disproportionately high in areas with residents of color.

Concentrations decreased in high-income cities around the world by 38%, but increased in other parts of the world with more residents in a lower socio-economic status.

While the data indicated the proportion of pediatric asthma cases attributable to nitrogen dioxide in urban areas declined from 20% in 2000, to 16% in 2019, pediatric asthma cases increased in South Asia by 23%, sub-Saharan Africa by 11%, North Africa and the Middle east by 5%.

Prior studies have linked exposure to particulate matter from air pollution to increased risk of asthma in children. Children exposed to air pollution are not only more likely to experience asthma and persistent wheezing, but also more likely to suffer from heart disease, high blood pressure, and other health problems as adults.

Air pollution is a modifiable risk factor, the researchers noted. When policies to reduce air pollution and other environmental stressors are enacted, health improves for the residents living in the affected areas. When nitrogen dioxide is reduced there are fewer asthma cases, but often the reductions are not seen across all areas of the world and communities with people of color are often disproportionately affected.

“Despite improvements in some regions, combustion-related nitrogen dioxide pollution continues to be an important contributor to pediatric asthma incidence globally, particularly in cities,” the researchers noted. “Mitigating air pollution should be a crucial element of public health strategies for children.”