Docstoc

rasp

Document Sample
rasp Powered By Docstoc
					      Toxic Air Pollution --- Current status of Air
                 Pollution in Sydney:
We all "know" that air pollution is bad for our health and have accepted a whole
series initiatives imposed by the Government aimed at reducing it. We have
accepted the banning of backyard burning. We have accepted the introduction of
unleaded petrol and catalytic converters on our cars and many other engine
design changes, even though they increased the cost of our cars. We have been
grateful to find that these actions have actually resulted in some reductions of air
pollution levels with both carbon monoxide and lead levels in the air falling to
roughly one third their previous levels. They are continuing to fall but at a slower
rate. Although this fall is thought to have had a measurable effect on general
health, it is still the sad fact that our air is continuing to make us sick. The main
cause of this is thought to be the increasing levels of ozone, volatile organic
chemicals, nitrous oxide and particulate matter present in the air we breathe.
The component of most concern appears to be fine particulate matter (PM2.5). A
major source of fine particulate matter in city air is diesel exhaust which contains
carbon particles carrying toxic and carcinogenic organic materials such as
benzene, complex sulphur and nitrate containing organic materials and reactive
ozone type compounds formed under the action of sunlight.
Particulate matter is known to cause increases in death rates and hospital
admissions round the world. What is lacking is an understanding of the
mechanism by which this happens and the Clinton administration provided $500-
600 million per year over ten years to find out what is causing 15,000 premature
deaths a year in the US and to " identify and evaluate … biological mechanisms
by which PM causes death and disease in humans."
Other air pollution components which are not in significant decline and therefore
in need of attention are the oxides of nitrogen, formed in ever greater quantities
as car and truck engines become more efficient and sulphur dioxide from high
sulphur fuels. Volatile organic compounds are under attack through a number of
initiatives to limit release and decrease use.
International and local evidence is over-whelming that such air pollutants present
a serious and costly health hazard. In September 2000, a ‘Lancet’ editorial
reported a recent study across Austria, France and Switzerland, that showed the
health costs of air pollution from traffic were 1.7% of the gross domestic product
and exceeded the cost of motor vehicle accidents. Dr Dockery, author of the
landmark ‘6-cities study’ in US, observes that the question is not whether
particulates are harmful, but at what level, and the levels are much lower than
previously thought.
A particularly clear indication of the extent to which vehicle based air pollution
effects health was observed in Atlanta during the Olympic games in 1996. Over
the games period, air pollution in Atlanta was reduced by about 20% with
reductions in ozone, carbon monoxide, particulate matter and nitrogen dioxide.
Over the same period hospital admissions for childhood asthma dropped by
44%, even though mould spores, the other potential major cause of asthma in
Atlanta did not change significantly. Other, non respiratory, hospital admissions
did not change markedly, showing the reduction was not caused by people
leaving the city. In general, the pollution levels experienced in Atlanta over the
whole of the study, before, during and after the games, were similar to those
experienced in Sydney during the year. The RTA predicts that the M5East stack
will cause increases in particulate matter and nitrogen dioxide in areas near the
stack, similar to or greater than those experienced in Atlanta, It follows that the
stack will cause increases in asthma attacks (and other respiratory illnesses) in
those areas.
As many people die in Sydney from air pollution as die in road crashes. The only
difference is they die slowly, and away from public view. Thousands regularly
suffer breathing difficulties, increased asthma and heart conditions. Increased
use of medication, hospitalisation and absenteeism are costs borne by the whole
community, not just the individuals and families involved.
Six Major Air Pollutants
(Prepared from the American Lung Association document on Problem Pollutants)
Almost all chemicals find their way into the air. But many are released in such
small amounts that they are not a health concern. Some substances are so
common and widespread they build up in the air and become a hazard to human
health.
Exposure to air pollution can make your eyes water, irritate your nose, mouth and
throat, and make you cough and sneeze. But more important, it can also worsen
and may cause lung disease like asthma, bronchitis and emphysema. In some
cases, it can even contribute to the premature death of people with heart and
lung disease.
SIX MAJOR AIR POLLUTANTS
The U.S. Environmental Protection Agency has developed health-based national
air quality standards for six pollutants. They are:
1. Carbon Monoxide
Carbon monoxide (CO) is an odourless, colourless, poisonous gas that comes
mainly from motor vehicles and other combustion exhaust.
Health effects: Carbon monoxide interferes with the blood's ability to carry
oxygen to the brain, heart and other tissues, and it is particularly dangerous for
people with existing heart disease, and unborn or newborn children.
2. Ozone
Ozone (O3) is the major harmful ingredient in smog. It is not emitted directly into
the air but produced in the atmosphere when gases or vapours of organic
chemicals called hydrocarbons combine with nitrogen oxide compounds in the
presence of sunlight. Organic hydrocarbon gases, one of the raw ingredients of
ozone, are released from a variety of sources related to human activities. Major
sources include refineries, gas stations, motor vehicles, chemical plants, paints
and solvents. Harmful ozone in the lower atmosphere should not be confused
with ozone in the upper atmosphere, which protects us from ultraviolet radiation.
Health effects: Ozone reacts with lung tissue. It can inflame and cause harmful
changes in breathing passages, decrease the lungs' working ability and cause
both coughing and chest pains. Ozone air pollution, found at unhealthy levels in
nearly all of the nation's major urban areas, may particularly affect millions of
otherwise healthy Americans who, for currently unknown reasons, are especially
sensitive to it. People who exercise are also more vulnerable to the effects of
ozone, suffering symptoms and a reduced ability to breathe at relatively low
ozone levels. Ozone pollution, even at low levels, has also been linked to
increased hospital admissions and emergency room visits for respiratory
problems.
3. Nitrogen Dioxide
Nitrogen dioxide (NO2) and related nitrogen oxides (NOx) are produced when
fuel is burned, especially in power plants and motor vehicles. These oxides of
nitrogen compounds contribute to ozone formation, and are a health problem
themselves. NO2 also changes in the atmosphere to form acidic particles and
liquid nitric acid.
Health effects: Both NO2 and NOx may threaten human health. Nitrogen dioxide
seems to act on the body like both ozone and sulfur dioxide.
4. Sulfur Dioxide
Sulfur dioxide (SO2) is created when sulfur-containing fuel is burned, primarily in
power-plants and diesel engines. Like NO2, sulfur dioxide can also change in the
atmosphere into acidic particles and into sulfuric acid.
Health effects: Sulfur dioxide constricts air passages, making it a problem for
people with asthma and for young children whose small lungs need to work
harder than adult lungs. Even brief exposure to relatively low levels of sulfur
dioxide can cause an asthma attack.
5. Particulate Matter
Particulate matter (PM) includes microscopic particles and tiny droplets of liquid.
These particles come from the burning of fuels by industry and diesel vehicles
and from earth-moving activities such as construction and mining.
Health effects: Larger particles can be stopped in the nose and upper lungs by
the body's natural defences. The smallest particles escape the body's defences
and go deep into the lungs, where they may become trapped. Exposure to
particulate pollution can cause wheezing and other symptoms in people with
asthma or sensitive airways. Particulate pollution has been linked to increased
hospital admissions and emergency room visits for respiratory problems and to a
substantial increase in premature deaths.
6. Lead
Lead (Pb) has been known as a poisonous substance for many years. Due to
past major reductions and now the elimination of lead in gasoline, there has been
a significant decrease in public exposure to lead in outdoor air. Remaining air
pollution sources include lead smelters, incineration of lead batteries, and
burning lead-contaminated waste oil. However, the most common sources of
current lead exposure are indoors from old lead-containing paint and soil.
Health effects: Exposure to high levels of lead can damage the blood, brain,
nerves, kidneys, reproductive organs and the immune system. Lower levels that
are more commonly associated with current exposures can result in impaired
mental functioning and development in children and raising blood pressure in
middle-aged men. Lead accumulates in the body, so repeated small doses can
be harmful.
TOXIC AIR POLLUTION
In addition to these six pollutants for which air quality standards have been set,
toxic air pollution, also referred to as hazardous air pollution, consists of those
substances in the air which are known or suspected to cause cancer, genetic
mutation, birth defects or other serious illnesses in people even at relatively low
exposure levels. Toxic and cancer-causing chemicals can be inhaled directly or
carried by small particles into the lungs. Millions of pounds of these chemicals
are emitted into the air over our nation every year by motor vehicles and by both
large and small industry.
Exposure to these toxic contaminants is regulated nationally by requiring the use
of pollution controls on these sources, rather than by air quality standards.
For more information visit the American Lung Association web site at http://www.lungusa.org.
Similar information is available on the NSW EPA web site ..http://www.epa.nsw.gov.au
http://savewollicreek.8m.com/ RAPS

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:21
posted:11/21/2010
language:English
pages:4