Millions of Cases of Asthma may be Caused by Chemicals in Air Pollution: New study

A new study has found that nearly 2 million new cases of pediatric asthma every year may be caused by a traffic-related air pollutant, a problem particularly important in big cities.  The study is the first to estimate the burden of pediatric asthma cases caused by this pollutant in more than 13,000 cities from Los Angeles to Mumbai.  Equally disturbing, a second study by the same research team finds that 1.8 million excess deaths around the world are linked to urban air pollution.

Study overview

Researchers studied “ground concentrations of nitrogen dioxide, or NO2, a pollutant that comes from tailpipe vehicle emissions, power plants and industrial sites. They also tracked new cases of asthma that developed in children from 2000 until 2019. Asthma is a chronic illness that causes inflammation of the lung’s airways.

Research findings overview

Out of the estimated 1.85 million new pediatric asthma cases attributed to NO2 globally in 2019, two-thirds occurred in urban areas.

The fraction of pediatric asthma cases linked to NO2 in urban areas dropped recently, probably due to tougher clean air regulations put in place by higher income countries like the United States.


Despite the improvements in air quality in Europe and the U.S., dirty air, and particularly NO2 pollution, has been rising in South Asia, Sub-Saharan African and the Middle East.

Pediatric asthma cases linked to NO2 pollution represent a large public health burden for South Asia and Sub-Saharan Africa.”

Additionally scientific findings

“A previous study by the GW researchers found that NO2 was linked with about 13% of the global pediatric burden of asthma and up to 50% of the asthma cases in the most populated 250 cities worldwide.

A second study by this research team found that 1.8 million excess deaths can be linked to urban air pollution in 2019 alone. This modeling study shows that 86% of adults and children living in cities around the world are exposed to a level of fine particulate matter that exceeds the guidelines set by the World Health Organization.”

Journal Reference:  Veronica A Southerland, Michael Brauer, Arash Mohegh, Melanie S Hammer, Aaron van Donkelaar, Randall V Martin, Joshua S Apte, Susan C Anenberg. Global urban temporal trends in fine particulate matter (PM2·5) and attributable health burdens: estimates from global datasets. The Lancet Planetary Health, 2022; DOI: 10.1016/S2542-5196(21)00350-8

Journal Reference: Susan C Anenberg, Arash Mohegh, Daniel L Goldberg, Gaige H Kerr, Michael Brauer, Katrin Burkart, Perry Hystad, Andrew Larkin, Sarah Wozniak, Lok Lamsal. Long-term trends in urban NO2 concentrations and associated paediatric asthma incidence: estimates from global datasets. The Lancet Planetary Health, 2022; 6 (1): e49 DOI: 10.1016/S2542-5196(21)00255-2