Around 40,000 infant deaths in Africa might have been avoided by reducing air pollution by 5 micrograms per cubic metre in 2015, suggests a modelling study published online this week in Nature.

Poor air quality is associated with death, disability and ill health, with exposure to ambient, breathable particulate matter of diameters less than 2.5 micrometres (referred to as PM2.5) having been linked to around 3-4 million deaths worldwide each year. However, these estimates are predominantly based on data from developed countries, which host the majority of air-pollution monitoring stations. By contrast, air pollution in sub-Saharan Africa is typically much higher, leaving an incomplete understanding on which to base policy decisions.

Marshall Burke and colleagues combined satellite-based data estimating the concentration of air pollutant particles with household health survey data on the location and timing of almost 1 million infant births (and any subsequent mortalities) from across sub-Saharan Africa between 2001 and 2015. They estimate that every 10-microgram-per-cubic-metre increase in PM2.5 concentration is associated with around a 9% increase in infant mortalities - an effect consistent over the 15-year study period. Furthermore, contrary to common expectations, the authors found that wealthier households were no better isolated from the negative effects of air pollution.

Using a risk model, the authors also estimate that a decrease in air pollution of 5 micrograms per cubic metre across Africa - a reduction equivalent to that achieved by the US Clean Air Act - might have averted around 40,000 infant deaths in 2015. The findings, the authors conclude, highlight the benefits of even modest reductions in air pollution in Africa to infant health.