Air pollution contributed to 1.8 million excess deaths in urban areas around the world in 2019, new research has suggested.

The two studies, published in The Lancet Planetary Health, aimed to explore the health impacts of ambient air pollution (particularly nitrogen dioxide and fine particulate pollution). 

The first paper, by Veronica Southerland and co-authors, looked at PM2.5 concentrations and mortality trends in more than 13,000 cities over a decade until 2019. While the particulate matter levels had declined in some parts of the world, it still continued to be an important public health risk factor in urban areas.

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The decreasing concentrations, for instance, did not always translate to a proportionate decrease in the mortality attributed to PM2.5, “revealing that other demographic factors, such as an ageing population and poor general health, are influential drivers of pollution-related mortality burdens,” an editorial in The Lancet wrote.

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The second study, also by researchers in the US, looked at the link between NO2 concentrations and paediatric asthma rates over the same time period.

The findings were alarming. In 2019, there were 1.85 million new paediatric asthma cases associated with NO2; 8.5% of all new paediatric asthma cases reported that year. In urban areas, NO2 was responsible for 16% of all new paediatric asthma cases in 2019.

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“Over the course of the study period the number of paediatric asthma cases in urban areas that could be attributed to NO2 pollution remained steady but the rate per 100 000 children decreased by 11% as the urban population grew. Despite effective air quality management benefiting children’s respiratory health in many regions, current NO2 levels contribute substantially to paediatric asthma incidence,” the editorial said. 

Dr Audrey de Nazelle, co-director of the Centre for Environmental Policy at Imperial College London, told Sky News that air pollution is dangerous because “it really attacks every organ in our body, it comes deep into our lungs, in some cases the very fine particles into the bloodstream and affects pretty much anything.”