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Air Pollution May Cause Lifelong Lung Deficits
By:
Per Elvingson
By
the age of 18, the lungs of
many children who grow up in
the polluted areas are underdeveloped
and are unlikely
ever to recover,
according to the results of the Southern California
Children’s Health Study, the longest investigation ever
into air pollution and children’s
health.
The study
provides the most
definitive
evidence yet that routine
exposure to
dirty air during childhood
actually harms
lung development,
leading to a
permanently reduced ability to breathe. Underpowered
lungs are
known to cause a wide range
of
health problems.
Between
1993
and 2001,
scientists
have tracked levels of major
pollutants in
twelve Southern
California
communities
while monitoring the pulmonary
health of1,759 children as they
progressed from 4th grade to
12th grade (10 to 18
years
old).
The twelve
communities included some of the most polluted areas in the greater Los
Angeles basin, as well as several low-pollution sites outside the area.
Children
breathing dirty air were
nearly five
times more likely than
children in
less polluted communities
to grow up
with weak lungs, they
found. In the
highest pollution areas
7.9 per cent of
the 18-year-olds had
lung
capacities that were less than
80% of what
they should have been.
Among teenagers
subjected to the
least-polluted
air, only 1.6 per cent
had
underperforming lungs. This is
some of the
most convincing evidence
that air
pollution has chronic effects.
The pollutants for
which a correlation was found between
concentration and deficits in
lung development were nitrogen
dioxide, acid vapour,
particulate matter with a
diameter of less than 2.5 microns and
elemental carbon. The strongest
correlation was observed with
small particulates. These are
pollutants that all derive from
vehicle emissions and
the combustion of fossil fuels.
The definition
of clinically low
lung function
is when a person has
less than 80
per cent of the lung
function
expected for his or her age.
This is viewed
as a significant deficit
with
both short and long-term
implications.
If a child or young adult with low
lung function were to have a cold, they might have more severe lung
symptoms, or wheezing. They may
have a longer disease course, while a
child with better lung function may
weather it much better.
Potential
long-term effects are
more alarming.
Low lung function has
been shown to
be second only to
smoking as a
risk factor for all-cause
mortality.
Lung function increases steadily as
children grow, peaking at about age
18 in women and sometime in the
early twenties in men. Lung
function stays steady for a
short time and then declines by 1 per cent a year
throughout adulthood. As lung
function decreases to low levels in
later adulthood, the
risk of respiratory
diseases and
heart attacks increases.
Researchers
are unsure how air
pollution
may
retard
lung
development. Chronic inflamma-tion
may play a
role, with air pollutants
irritating
small air ways on a daily
basis.
Scientists also suspect that
pollutants
might inhibit the growth of
alveoli, the
tiny air sacs within the
lungs where the
exchange of oxygen
and carbon
dioxide takes place.
The research team will continue
to follow the
study participants into
their early
twenties, when their lungs
will mature and
stop developing
entirely. The
team aims to find out if
the
participants begin to experience
respiratory
symptoms and if those who
moved away
from a
polluted
environment show benefits.
The Swedish NGO secretariat on Acid
Rain, Box 7005, 402 31 Goteborg,
Sweden
(Source: Acid News, Sweden) |
