Air pollution's connection to infant mortality

Date:
June 29, 2020
Source:
Stanford University
Summary:
The study of sub-Saharan Africa finds that a relatively small
increase in airborne particles significantly increase infant
mortality rates. A cost- effective solution may lie in an
exotic-sounding proposal.



FULL STORY ==========================================================================
Dust sweeping across the Southeast U.S. in recent days warns of a growing
risk to infants and children in many parts of the world. A Stanford-led
study focuses on this dust, which travels thousands of miles from
the Sahara Desert, to paint a clearer picture than ever before of air pollution's impact on infant mortality in sub-Saharan Africa. The paper, published June 29 in Nature Sustainability, reveals how a changing climate might intensify or mitigate the problem, and points to seemingly exotic solutions to reducing dust pollution that could be more effective and affordable than current health interventions in improving child health.


========================================================================== "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
study senior author 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, a known cause of poor health." Understanding airborne danger Children under 5 are particularly vulnerable to the
tiny particles, or particulate, in air pollution that can have 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.

Quantifying the health impacts of air pollution -- a crucial step for understanding global health burdens and evaluating policy choices
-- has been a challenge in the past. Researchers have struggled to
adequately separate out the health effects of air pollution from the
health effects of activities that generate the pollution. For example,
a booming economy can produce air pollution but also spur developments,
such as lower unemployment, that lead to better healthcare access and
improved health outcomes.

To isolate the effects of air pollution exposure, the Stanford-led study focuses on dust carried thousands of miles from the Bode'le' Depression
in Chad -- the largest source of dust emissions in the world. This dust
is a frequent presence in West Africa and, to a lesser extent, across
other African regions.

The researchers analyzed 15 years of household surveys from 30 countries
across Sub-Saharan Africa covering nearly 1 million births. Combining
birth data with satellite-detected changes in particulate levels driven
by the Bode'le' dust provided an increasingly clear picture of poor air quality's health impacts on children.

Sobering findings and surprising solutions The researchers found
that a roughly 25 percent increase in local annual mean particulate concentrations in West Africa causes an 18 percent increase in infant mortality. The results expand on a 2018 paper by the same researchers that found exposure to high particulate matter concentrations in sub-Saharan
Africa accounted for about 400,000 infant deaths in 2015 alone.

The new study, combined with previous findings from other regions, makes
clear that air pollution, even from natural sources, is a "critical
determining factor for child health around the world," the researchers
write. Emissions from natural sources could change dramatically in a
changing climate, but it's unclear how. For example, the concentration
of dust particulate matter across Sub-Saharan Africa is highly dependent
on the amount of rainfall in the Bode'le' Depression. Because future
changes in rainfall over the Bode'le' region due to climate change are
highly uncertain, the researchers calculated a range of possibilities
for sub-Saharan Africa that could result in anywhere from a 13-percent
decline in infant mortality to a 12-percent increase just due to changes
in rainfall over the desert. These impacts would be larger than any other published projections for climate change impact on health across Africa.

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 in the Bode'le' region to stop it from
going airborne -- an approach that has been successful at small scale
in California.

The researchers estimate that deploying solar-powered irrigation
systems in the desert area could avert 37,000 infant deaths per year
in West Africa at a cost of $24 per life, making it competitive with
many leading health interventions currently in use, including a range
of vaccines and water and sanitation projects.

"Standard policy instruments can't be counted on to reduce all forms of
air pollution," said study lead author Sam Heft-Neal, a research scholar
at Stanford's Center on Food Security and the Environment. "While our calculation doesn't consider logistical constraints to project deployment,
it highlights the possibility of a solution that targets natural pollution sources and yields enormous benefits at a modest cost."

========================================================================== Story Source: Materials provided by Stanford_University. Original written
by Rob Jordan.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Sam Heft-Neal, Jennifer Burney, Eran Bendavid, Kara K. Voss,
Marshall
Burke. Dust pollution from the Sahara and African infant mortality.

Nature Sustainability, 2020; DOI: 10.1038/s41893-020-0562-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200629120215.htm

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