Air_Pollution - Air Pollution Primary Pollutants Primary...

Air Pollution

Primary Pollutants
• Primary Pollutants – emitted directly into
the air from natural sources such as
volcanoes, mobile sources (cars), or
stationary sources such as industrial
smokestacks
• Primary pollutants include:
– Particulate matter (PM
10
)
– Nitric oxide (NO), Nitrogen dioxide (NO
2
)
– Sulfur dioxide (SO
2
)
– Carbon dioxide (CO
2
) and Carbon monoxide (CO)

Secondary Pollutants
• Secondary Pollutants – result from
reaction of primary pollutants in the
atmosphere to create a new pollutant
• Secondary pollutants include:
– Sulfur trioxide (SO
3
)
– Sulfuric acid (H
2
SO
4
)
– Ozone (O
3
)
– Chemicals in photochemical smog
• PANS and peroxyacyl nitrates

Major Air Pollutants
• NITROGEN DIOXIDE (NO
2
)
– Forms when fuels are burned at high temps
– Results from forest fires, volcanoes,
lightning, and bacterial action in soil
– Forms nitric acid (HNO
3
) in air and
contributes to acid deposition and cultural
eutrophication
– Results in lung irritation and damage,
suppresses plant growth, and may cause
cancer

Major Air Pollutants
• OZONE (O
3
)
– Major component of photochemical smog
– Formed by sunlight reacting with NO
x
and
VOC’s
– Causes lung irritation and damage, bronchial
constriction, coughing, wheezing, and eye
irritation
– Damages plants, rubber, and plastics

Major Air Pollutants
• SULFUR DIOXIDE (SO
2
)
– Produced by burning high sulfur oil or coal,
smelting metals, and paper manufacturing
– Combines with water vapor to produce acid
precipitation, which reduces plant
productivity
– Causes breathing difficulties
– Significant decreases in the U.S. reflect the
success of the Acid Rain Program and the
Clean Air Act

Major Air Pollutants
• SUSPENDED PARTICULATE MATTER (PM
10
)
– Particles with diameter 1/7 the width of a
human hair or less (<10 µ m)
– Includes smoke, dust, diesel soot, lead,
asbestos
– Cause lung irritation and damage and many
are mutagens, teratogens, and carcinogens
– Reduction of PM
10
’s would produce health
benefits 10 times greater than similar
reductions in other pollutants

Major Air Pollutants
• VOLATILE ORGANIC COMPOUNDS (VOC’s)
– Organic compounds that have a high vapor
pressure (over 600 compounds identified)
– Examples include toluene, xylene,
formaldehyde, benzene, and acetone
– Many are found in paints, aerosol sprays, dry-
cleaning fluids, and industrial solvents
– Cause respiratory irritation and damage, and
most are cancerous & cause liver, kidney, and
nervous system damage
– Concentration of VOC’s may be 1000 times
greater indoors than outdoors!!