UIGIMAGES
Recently, there were reports of gaseous air pollution in Lagos. Twenty five pupils of a secondary school had fainted after inhaling fumes from an industrial plant.
Up
till now, the authorities are still “looking” for the responsible “gas”.
Over
the years, when it comes to air pollution, its deleterious effect has centred
on the effect of gases on the lungs and respiratory diseases.
But
that has changed.
Last
month, the specialised cancer agency of the World Health Organisation, the
International Agency for Research on Cancer, classified outdoor air pollution
as carcinogenic to humans (Group 1).
The
major cancers are those of the lungs and bladder.
Sadly,
there’s more.
There
is now mounting evidence that air pollution also plays a role in heart attacks
and strokes. In fact, new research does not only say it worsens cardiovascular
disease, but it causes it.
Sara
Adar, a professor of epidemiology at the University of Michigan, said, “We’ve
known for about 20 years that we see increased risk of heart attack and stroke
in association with increased levels of air pollution,” adding that the most
recent data show that “air pollution does more than just make you worse.”
The
culprits are fine particulates that mix with dangerous gases in the air. They
measure 2.5 microns or less and act by penetrating deep into the lungs, and
embedding in tissue and starting off a cascade of inflammatory reactions. It is
believed that the inflammation also spreads into the circulatory system,
changing the way blood vessels function.
Deborah
Blum, a columnist on the environment, said that although air pollution is a
long-known and regulated health hazard, only gradually have researchers come to
appreciate the threat of particulates. She said in 1989, C. Arden Pope III, a
professor of economics at Brigham Young University, published a paper based on
the temporary shutdown of a nearby steel mill, showing a linear relationship
between emissions and hospitalisation. He traced the illnesses to particulates
in the air.
Blum
went further to say that Pope had initially focused on air pollution’s effects
on the lungs, but over the years he kept turning up increases in cardiovascular
disease. She said by 2002, Pope had given up on the idea that this was just
some anomaly in the study design. Eventually, he identified the culprit: fine
particles, far smaller than those tracked in his original steel mill study.
“The deeper you dive into the data, the more clearly you see the effect on
cardiovascular disease,” Pope had said.
Adar
and her colleagues have been studying the damage at the microscopic level in
the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), where
they followed more than 5,000 people in six states for more than a decade.
Adar
and co-researchers have shown that increased exposure to pollutants, after
other factors are factored out, can be directly linked to narrowing of blood
vessels and to a gradual thickening of artery walls.
Their
current study, published this year in PLoS Medicine,
expressed a near-linear relationship: As air pollution levels dropped, the
thickening slowed. But when exposure to air pollutants increased, signs of
damage increased.
Furthermore,
many researchers believe that vehicle pollution leads to changes in heart rate.
A study published this year in Environmental Health found support of “acute changes” in heartbeats
in people, aged 22 to 56, who were driving in Mexico City traffic. Another
recent study, of bicyclists in Ottawa, Canada, found that their heart rhythms
seemed to be altered for hours after they had got home in ways unconnected to
exertion.
What’s
more, air pollution, even at low levels, is associated with a significant
increase in the risk for low-birth-weight babies. This was following a report
published online in The Lancet Respiratory
Medicine.
European
researchers gathered data from 14 studies that had more than 74,000
mother-child pairs in 12 countries. The scientists also estimated
concentrations of airborne particulate matter at the mothers’ home addresses
during their pregnancies.
Concentrations
of particulate matter even as low as 20 micrograms per cubic metre were linked
to an increased risk of giving birth to a full-term low-birth-weight baby, the
researchers discovered. After controlling for a variety of factors, the
researchers estimated that each five microgram per cubic metre increase in
particulate matter was associated with an 18 per cent increase in the risk for
low birth weight.
Moreover,
researchers have even added appendicitis as a further risk of air pollution.
The
researchers studied 35,811 patients hospitalised for appendicitis in 12 Canadian cities between 2004 and 2008. They used air
pollution data they got from monitors in each city to calculate daily maximum
concentrations of ozone, a normal component of the earth’s upper atmosphere
that becomes a danger when concentrated at ground level.
It
was found that high ozone levels were linked with an increased number of
hospitalisation for appendicitis and were even more strongly associated with
cases of burst appendix. For each 16 parts per billion increase in ozone
concentration, the scientists found an 11 to 22 per cent increase in ruptured
appendix cases. The study was published in the Environmental Health Perspectives.
Not
forgetting the effect of air pollution on the brain, particularly cognitive
deterioration.
We
may not have to look further for causes of “unexplained” stroke and sudden
death attributed to “enemies”.
Now
that we know, Nigerians must begin to demand more from government.
We
must find better ways of identifying and controlling air emissions.
But
perhaps the most effective way of preventing the problems associated with air
pollution, is through effective environmental regulation.
Dr Cosmas Odoemena
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