Nearly 2 million new cases of pediatric asthma each year can be caused by traffic-related air pollutants, a problem particularly important in major cities around the world, according to a new study published today. The study was the first to assess the severity of pediatric asthma cases caused by the pollutant in more than 13,000 cities from Los Angeles to Mumbai.
Our study found that nitrogen dioxide puts children at risk of developing asthma and the problem is particularly acute in urban areas. The results show that clean air must be a critical part of strategies aimed at maintaining children’s health. “
Susan Annenberg, co-author and professor of environment and occupational health, George Washington University
Annenberg and her colleagues studied ground-level concentrations of nitrogen dioxide or NO2, a pollutant that comes from exhaust emissions from vehicles, power plants and industrial sites. They are also tracking new cases of asthma that are developing in children from 2000 to 2019. Asthma is a chronic disease that causes inflammation of the airways in the lungs.
Here are some key findings from the study:
- Of the approximately 1.85 million new cases of pediatric asthma attributed to NO2 worldwide in 2019, two-thirds occurred in urban areas.
- The proportion of pediatric asthma-related cases of NO2 in urban areas has recently declined, probably due to tighter clean air regulations introduced by higher-income countries such as the United States.
- Despite improvements in air quality in Europe and the United States, polluted air and especially NO2 pollution are on the rise in South Asia, sub-Saharan Africa and the Middle East.
- Cases of pediatric asthma related to NO2 pollution pose a major public health burden for South Asia and sub-Saharan Africa.
A previous study by GW researchers found that NO2 is associated with about 13% of the global pediatric burden of asthma and up to 50% of asthma cases in the world’s 250 most populous cities.
Overall, the proportion of NO2-related cases of pediatric asthma has fallen from 20% in 2000 to 16% in 2019. This good news means that cleaner air in Europe and parts of the US has led to large health benefits for children, especially those living in neighborhoods close to busy roads and industrial sites.
Much more needs to be done, both in higher-income countries and in parts of the world that are still struggling to reduce emissions from vehicles and other sources of NO2, the researchers concluded.
A second study by Veronica Sutherland of GW, Anenberg and their colleagues found that 1.8 million deaths could be linked to urban air pollution in 2019. This modeling study shows that 86% of adults and children living in in cities around the world are exposed to a level of fine dust particles that exceeds the guidelines set by the World Health Organization.
“Reducing fossil fuel transport can help children and adults breathe easier and can pay big health dividends, such as fewer cases of pediatric asthma and excessive deaths,” Annenberg said. “At the same time, it will also reduce greenhouse gas emissions, which will lead to a healthier climate.
Both studies appear on January 5 in Lancet Planetary Health.
George Washington University