Good
up High, Bad Nearby
Ozone
is a highly reactive form of oxygen. Stratospheric ozone
or "good"
ozone occurs 10 to 30 miles above the Earth’s surface
and shields us from the sun’s ultraviolet rays. When
people talk about wearing extra sunscreen to protect them
from sun damage due to the hole in the ozone, they are speaking
of upper stratospheric ozone. Ground level ozone, or "bad" ozone,
is created in the lower atmosphere when pollutants cook on
hot sunny days. In North Carolina, ozone is our most
widespread air quality problem and the main component in
urban smog.
Ozone is a colorless, odorless gas. Don’t depend on
the horizon line to indicate whether it is a high ozone day.
When ozone mixes with other pollutants it can create a visible
smog layer but because it is a colorless gas, a high-level
ozone day could be sunny, clear and damaging to your health.
The peak time for ozone is between May and September, the
hot weather months, and levels escalate as the outside temperature
heats up.
Where does Ozone come from?
Ozone is created when
VOCs, (Volatile Organic Compounds), mix with NOx, (Nitrogen
Oxides), and cook in the presence
of hot sunlight. VOCs come from many things with strong odors,
such as paint thinner, furniture lacquer, gas fumes, dry
cleaners,
cleaning products and natural sources such as trees. The
biggest producer of VOCs are the pine, oak and other trees
growing
abundantly across North Carolina.
Cutting down trees to reduce VOCs and
combat ozone is not a solution so we have to look at the
other
half of the equation – NOx. NOx is created by fuel
burning combustion in motor vehicles, power/industrial plants,
lawn
care equipment, motorboats and other water sports equipment,
and construction equipment. Statewide, over 50% of our NOx
come from point sources, which are power plants and other
smokestack sources. However, in our urban areas, 54 % of
NOx
emissions come from highway mobile, meaning cars and trucks
on the highways. Another 40% comes from non-highway mobile,
meaning construction vehicles, lawn care equipment, and water
sports equipment.
Ozone levels are generally higher in urban areas, which contain
more cars, industry and other emissions sources. However,
winds can carry ozone from cities to surrounding rural area
and even to other states.
Ozone and your Health
People
might not be able to see it, but ozone irritates their lungs.
The American Lung Association
recently published it’s
2002 State of the Air report listing people at risk in America’s
25 most ozone polluted cities. Charlotte was ranked 9th,
The
Triangle 13th and the Triad 21st in the nation. We have serious
reason to be concerned about our air quality and the health
ramifications of living in such a polluted environment.
Roughly one out every three people in the United States is
at a higher risk of experiencing ozone-related health effects.
Active children are the most high-risk group for ozone exposure
because they spend a large part of the summer playing outdoors,
they breath more air per pound of body weight, their lungs
are still developing and they are more likely to have asthma
and other respiratory illnesses. Children make up 40% of all
asthma cases but only 25% of the population. Recent studies
indicate that children who are active in high ozone environments
have diminished lung capacity and are at risk of developing
asthma and other respiratory illnesses or exacerbating pre-existing
respiratory problems.
Though scientists don’t yet know why, some healthy people
experience health effects at more moderate levels of outdoor
exertion or at lower ozone levels than the average person.
Ozone can irritate the respiratory system causing coughing,
throat irritation and/or an uncomfortable sensation in the
chest. It can inflame and damage the lining of the lungs,
much like sunburn on the inside of the lungs. Studies suggest
that if this happens repeatedly over months or years, the
lung tissue may become permanently scarred, resulting in less
lung elasticity, reduced or permanent loss of lung function,
and a lower quality of life. Ozone can aggravate asthma and
other respiratory diseases and reduce the immune system’s
ability to fight off bacterial infections in the respiratory
system. Exposure to higher levels of ozone can accelerate
the natural decline in lung function that occurs as part
of
the normal aging process.
Ozone damage can occur without any noticeable signs. People
who live in high ozone areas may find that their initial
symptoms
go away over time but lung damage can continue to occur even
when the symptoms have disappeared. The best way to protect
your health and the health of your family is to KNOW THE
CODE.
Familiarize yourself with the AQI and the ozone forecast
and take simple precautions to minimize exposure even when
you
don’t feel obvious symptoms.
Environmental Effects of Air Pollution
The
pollution we create doesn’t just cause air quality
problems, it can also contaminate our water systems. SO2 (Sulfur
dioxide) and NOx (nitrogen oxide) are created when fossil
fuels are burned. These pollutants rise into the air where
they are absorbed into clouds, transported by wind, and deposited
into streams, lakes and ground water by rain and fog in a
process known as acid deposition. This acid deposition or
acidification of lakes, streams, and soils negatively impacts
aquatic and terrestrial habitats and causes reproductive problems
or failure in native fish. Studies have measured certain rain
clouds with acidic concentrations close to that of vinegar.
In addition, airborne NOx, deposited by rain into waterways,
contributes to nutrient pollution or eutrophication, resulting
in low oxygen levels, fish kills and other effects. It’s
estimated that a third of nitrogen pollution in Albemarle
and Pamlico sounds comes from airborne sources.
Ground level ozone has caused an estimated 3 billion dollars
a year in reduced crop production in the United States, affecting
such crops as soybeans, wheat, kidney beans, and cotton. Ozone
interferes with the ability of plants to produce and store
food and makes them more susceptible to disease, insect infestation,
environmental stresses and other pollutants.
The burning of fossil fuels creates sulfate particles, which
contribute to the haze we see in the summer. These tiny airborne
particles scatter white light resulting in a white haze that
degrades visibility. During the summer, on the Appalachian
Trail in the Smokies, pollution can be worse than in most
cities in the East – including New York City. Over
the years, visibility in the Smokey Mountains has been reduced
from 93 miles to 22 miles. The Smoky Mountains did not get
their name from this man-made pollutant haze. Rather, the
name comes from the blue color of the mountains when seen
from afar. Naturally occurring VOCs from the trees give the
air a bluish cast without reducing visibility. During some
particularly bad man made pollutant haze episodes, visibility
in the Smokies can shrink to one mile.
For more information, visit the N.C.
Division of Air Quality and EPA's
AIRNow
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