Pollution's impact on child health

Date:
October 14, 2021
Source:
Stanford University
Summary:
Air pollution is known to harm children's respiratory health, but
its specific impacts on infection rates have remained unclear. A new
analysis provides evidence of a link between the two in low-income
settings, and indicates one industry may play an outsized role in
the problem.



FULL STORY ========================================================================== Studies have shown air pollution is a major risk factor for respiratory infection -- the leading cause of death among children under five -- but
bad air's specific impacts on developing bodies have remained somewhat
of a mystery.


==========================================================================
A Stanford-led study reveals a link between tiny airborne particles and
child health in South Asia, a region beset with air pollution and more
than 40 percent of global pneumonia cases. The analysis, published in Environmental Pollution, estimates the effect of increased particulate
on child pneumonia hospitalizations is about twice as much as previously thought, and indicates a particular industry may play an outsized role
in the problem.

The findings could help public health officials and policymakers better
target emissions reduction programs to improve child health.

"Everybody wants to protect kids' health," said study lead author
Allison Sherris, a postdoctoral research fellow in Earth system science
at Stanford's School of Earth, Energy & Environmental Sciences. "Now,
we have evidence of a clear health benefit to children from reducing
ambient PM2.5 emissions in Dhaka." For many of the 21 million residents
of Dhaka, Bangladesh -- the study's focus area -- air pollution is an all-too-regular part of life, especially in winter, when coal-burning
brick kilns around the city operate. Of special concern is PM2.5, airborne particles 2.5 micrometers wide or smaller. The larger of these particles
are about one-thirtieth the width of a human hair, small enough to inhale
deep into the lungs.

Once inside the lungs, these particles can cause inflammation and impair
the body's ability to fight infection. But particles from different
sources can have different shape, size and chemical composition, and
it's not clear what specific components of PM2.5 might be most harmful.



==========================================================================
Few studies have evaluated the health effects of PM2.5 in infants and
young children, especially in low-income countries where children are
more than 60 times as likely to die from air pollution exposure as
children in high-income countries, according to the World Bank. Among
studies that have, most focused on the indoor environment, where the use
of biomass-burning cookstoves has been associated with child respiratory infection.

"Specifying the impact of industry-generated air pollution on child
health provides compelling evidence to support interventions to
reduce pollution," said study senior author Stephen Luby, a professor
of infectious diseases at Stanford University. "This is often more
salient to politicians than the marginal contribution of emissions to
global climate change." Sherris, Luby and their colleagues analyzed
long-term PM2.5 monitoring data alongside community health surveillance
of respiratory infections from the Atomic Energy Centre, Dhaka, and the International Centre for Diarrhoeal Disease Research, Bangladesh. They
found pneumonia incidence among children under 5 increased by 3.2 percent
for every PM2.5 increase of 10 micrograms per cubic meter of air --
a standard measure in air pollution analysis.

The mean PM2.5 level in Dhaka was on average over three times higher
than the World Health Organization standard. The association between
air pollution and child pneumonia suggests that air pollution is a major contributor to the leading cause of child death in Bangladesh and across
South Asia.

That difference equates to more than 200,000 additional child pneumonia
cases in Bangladesh each year, and nearly two million additional cases
across South Asia. The increase is also approximately double similar
prior estimates of pneumonia hospitalizations associated with increased
PM2.5 and about 10 times more than such estimates for outpatient visits.

The difference from previous findings may reflect the young age of the
study population -- most children in the study were two or younger --
the source composition of particulate matter in Dhaka, and the fact
that the study included nearly all community infection cases, rather
than just focusing on cases that made it to clinics and hospitals.

Prior studies by researchers at the Atomic Energy Centre, Dhaka found
that biomass burning contributed the most to outdoor PM2.5 levels,
followed by brick kiln emissions and soil dust. However, on days when
brick kilns contributed a heavier than-usual amount of PM2.5 to the mix
of bad air, the link between PM2.5 and child pneumonia was stronger.

The findings are among the first evidence that communities and
policymakers can point to that suggests a measurable impact of brick
kilns on child health.

Considering 9 out of 10 people live in areas with air pollution exceeding
World Health Organization guidelines, further investigation into whether particles from brick kilns and other sources have different health
impacts could inform health and environmental interventions around the
world. Luby leads a collaboration among public health experts, industry stakeholders, technology consultants and government agencies to improve
the industry. He received funding for related work focused on brick kilns
and other industries, funded by the Sustainability Initiative that gave
rise to Stanford's new school focused on climate and sustainability.

"We're still only looking at a small slice of the potential health
outcomes that might be linked to this kind of air pollution, and we
still lack perfect measurements of exposure to it," said Sherris. "The
true health burden is likely much greater.

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

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Allison R. Sherris, Bilkis A. Begum, Michael Baiocchi, Doli Goswami,
Philip K. Hopke, W. Abdullah Brooks, Stephen P. Luby. Associations
between ambient fine particulate matter and child respiratory
infection: The role of particulate matter source composition in
Dhaka, Bangladesh.

Environmental Pollution, 2021; 290: 118073 DOI: 10.1016/
j.envpol.2021.118073 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211014142021.htm

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