Air pollution from traffic and industrial activities has come up again, but a new Stanford-led study highlighted that air pollution, even from natural sources e.g. dust which travels thousands of miles from sub-Saharan Africa, is critical in determining infant mortality and overall child health around the world.

The Stanford researchers found that a roughly 25% increase in mean dust particulate concentrations in West Africa caused an 18% increase in infant mortality – the results echo past findings that found exposure to high particulate matter concentrations in sub-Saharan Africa accounted for about 400,000 infant deaths in 2015 alone.

Children under 5 are particularly vulnerable to the tiny particulates in air pollution. It can cause a range of negative health impacts, including lower birth weight and impaired growth in the first year of life. In developing regions, exposure to high levels of air pollution during childhood is estimated to reduce overall life expectancy by 4-5 years on average.

“Africa and other developing regions have made remarkable strides overall in improving child health in recent decades, but key negative outcomes such as infant mortality remain stubbornly high in some places,” said Marshall Burke, an associate professor of Earth system science in Stanford’s School of Earth, Energy & Environmental Sciences. “We wanted to understand why that was, and whether there was a connection to air pollution.”

The research community has struggled to adequately separate out the health effects of air pollution from the health effects of activities that generate it. For example, a booming economy can produce air pollution but also spur developments that lead to better healthcare access and improved health outcomes.

However, safeguarding children against air pollution is nearly impossible in many developing regions because many homes have open windows or permeable roofs and walls, and infants and young children are unlikely to wear masks.

Instead, the researchers suggest exploring the possibility of dampening sand with groundwater to stop it from going airborne – the researchers calculated a range of possibilities for sub-Saharan Africa that could result in anywhere from a 13% decline in infant mortality to a 12% increase just due to changes in rainfall over the desert.

These impacts would be more significant than any other published projections for climate change impact on health across Africa, including the use of a range of vaccines and water and sanitation projects.