Dust%20to%20dust:%20effects%20of%20airborne%20particulates

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Dust to dust effects of airborne particulates
(and ground level ozone) on human health
Mexico City
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Particulates (airborne particles of solid matter,
and tiny droplets of liquid matter with dissolved
components) include a wide variety of substances,
from inorganic mineral and rock particles to
organic dust
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Are All Particulates Harmful? No ! Not all
particulates have adverse effects on human
health. For example, volcanic eruptions emit
huge amounts of inorganic particulates (ash) into
the atmosphere that, in natural concentrations,
do not harm humans to a significant degree Also,
there is also no evidence that sea salt --
another form of inorganic particulate in the
atmosphere, results in adverse effects on
health. Butis good evidence to link some
particulates from combustion to serious effects
on health The key is CONCENTRATION. High enough
concentrations of any particulate can be bad.
Also, some particulates are more harmful than
others in terms of how they interact with the
functioning of the human body.
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On a large scale, much of our pollution
comprises abundant dust generated from open
sources (e.g. open fields, roads, etc.),
transportation, combustion of materials and
industry/mining
Principal types and sources of air pollution in
Canada per unit mass
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Particulate pollution is not restricted to urban
areas From a public health perspective, air-borne
small particulate from combustion (e.g. wood
burning) and open pit mining, is now considered
to be the single greatest air pollution problem
in British Columbia. Scientific research
indicates that increased levels of this small
particulate are responsible for a marked increase
in Emergency Room visits, hospitalizations, and
days lost from school and work.
Study by American Lung Association
(1995) Indicated that air pollution from
particulates, produced by the burning of fossil
fuels and other materials, was determined to have
caused thousands of deaths and cost the national
economy some 11 billion (US) each year
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General Consequences on Human Health
Particulate air pollution has been closely linked
to aggravation of existing heart and lung
conditions and even increased death rates (puts
stress on respiratory system). Children and
senior citizens are most vulnerable -- a recent
study estimated that small particle pollution is
responsible for many thousands of premature
deaths annually in the North America. Studies
of small particulate air pollution also indicate
a significant increase in the population death
rate in areas suffering prolonged exposure to
this type of pollution.
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Perhaps one can get a better appreciation
of particulate pollution by looking at an urban
setting
Welcome back to Beijing -but are we really in
the position to point the finger ?
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Smog A Common Urban Problem
What is smog ? Word derived from smoke and
fog What is smog made of ? A variety of
substances, but primary components are
particulates (solids and liquid droplets) and
ground level ozone (O3) What kinds of
particulates ? - Solid particles emitted from
combusted material - Volatile organic compounds
(VOCs) compounds of mostly carbon and hydrogen,
but which also contain oxygen, nitrogen,
chlorine, sulphur and phosphorus (sources motor
vehicles, evaporated of gasoline, oil-based
paints, nail polish remover, barbecues, surface
coatings, inks and hydrocarbons from the
petrochemical industry)
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What makes smog hazy and brown ?
One would think it is from solid particles. But
while solid particles do occur in smog, it is
mostly the nitrogen dioxide that colours the
stagnant air.
Montreal
Toronto
Hamilton
London (the other one)
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What conditions cause smog ?
High particulate content of air Plus certain
weather conditions, especially -warm
temperatures ranging from the high 20s
up -still, stagnant air (slow wind speeds)
Often associated with thermal inversion, when
warm air mass presses down on lower, cooler air
mass, trapping pollution-laden air close to the
ground
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Where and when does smog occur ?

• Tends to occur in densely populated urban areas
  (duh!) and valleys where warm air masses become
  trapped and remain stagnant
• Smog season in Canada about May through
  September
• Worst places in Canada for smog
• the urban belt running from Windsor to Quebec
  (some from Canada, lots from U.S. in summer)
• Atlantic Canada (mostly from polluted air of
  urban centres along the eastern United States-
  thank you G. dubyuh ! )
• Lower Fraser Valley (British Columbia)
• Worst time of the day for smog late afternoon to
  early evening

Note wind direction ! Call it free trade
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But isnt lots of ozone a good thing ?
Ground-level ozone is the same kind of ozone
found in the stratosphere (15 to 30 kilometres
above the ground) that shields us from the sun's
harmful ultraviolet rays. Ozone (O3) is
basically just regular oxygen molecule (O2)
combined with another oxygen atom. But ozone is
formed differently in the stratosphere than at
ground level Stratospheric ozone is produced
when oxygen molecules are split into atoms when
bombarded by uv radiation. The single atoms (O)
then combine with regular oxygen molecules (O2)
to form ozone (O3) .
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Ground Level Ozone
Ground level ozone forms in a different way (is
dependent on high concentrations of
pollutants) Involves nitrogen oxides and a
variety of organic molecules that split apart in
strong sunlight For example, a single oxygen
atom is given off by this reaction NO2 uv
light NO O The lone oxygen atom then
combines with a regular molecule of oxygen (O2)
to form ozone (O3) O O2 O3 More complex
reactions also occur (especially those involving
organic compounds), but you get the point
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Ground Level Ozone
So the formation of ground level ozone feeds
on other pollutants generated by fossil fuel use
on warm, sunny, summer days
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Effects of High Levels of Ground Level Ozone
At ground level, high levels of ozone can harm
people, animals and vegetation (it is very
reactive- hence its use in killing bacteria in
the purification of bottled water) -irritates
lung airways -short term symptoms include
wheezing, coughing, pain when taking a deep
breath, and breathing difficulties -may cause
permanent lung damage after long-term
exposure -in plants, high levels of ozone prevent
plants from producing and storing food (in turn
makes them more prone to disease, pest
infestations, and harsh weather).
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How does smog affect humans ?

• Soon a general level, we can say that smog
  affects the cardio-respiratory system of people.
• More specifically, it can cause
• mild respiratory distress
• coughing
• asthma
• bronchitis
• reduced resistance to lung infections and colds
• eye irritation
• Obviously, symptoms tend to be worst when smog is
  worst
• Also, volatile organic compounds, many of which
  are not terribly dangerous themselves, can serve
  as vehicles for carcinogenic organic molecules
  that normally occur in trace quantities (so
  possible long-term implications to smog exposure)

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What do I do when there is a smog warning ?
reduce physical activity, especially activity
outside. restrict the amount of time young
children spend outside. people with
pre-existing respiratory problems should consult
their physician about how much time to spend
outside and what precautions to take.
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End of lecture