Criteria Pollutants

1
Criteria Pollutants

• Determining the standards of our air quality

2
Background

• The late 40s and 50s brought about a noticeable
  change in air quality.
• Densely populated areas reported their first
  episodes of Smog
• Research indicated that the culprit was burning
  fossil fuels
• Most distressing was the fact that chemicals were
  found in the entire ambient air.

3
Background

• Research was conducted to determine whether these
  chemicals were dangerous to the human body
• Several studies indicated that yes, there was in
  fact a significant risk.
• Eye irritation, bronchitis, sore throat.
• By the 70s enough data existed on the common
  chemicals to regulate their levels

4
Background

• The U.S. EPA (environmental Protection Agency)
  established ambient air quality standards for six
  of the most common pollutants

5
Criteria pollutants

• Particulate matter (PM)
• Sulfur Dioxide (SO2)
• Nitrogen Oxides (NOX)
• Carbon Monoxide (CO)
• Ozone (O3)
• Lead (PB)

6
Particulate Matter

• Original standard applied to all particulate
  matter
• Modified to restrict only to matter that is less
  then 10 micrometers in diameter
• hence the term PM10
• Only the very tiniest particles have the
  potential to affect the human body greatly

7
Particulate matter

• Common by product of most combustion processes
• dust, fine sand, and other debris can also
  produce PM10
• Construction activities, logging, mining create
  PM10
• also aids acid rain by providing a condensate
  material.

8
Sulfur Dioxide

• Most comes from coal and oil combustion
• primary sources are coal powered electric plants.
• Associated with the rise of respiratory disease.
• Key factor in the development of acid rain.

9
Nitrogen Oxides

• Common by product of fossil fuel combustion
• NO2 can irritate the respiratory pathways
• increases succeptability to viral infection
• precursor to acid rain
• Stunts plant growth
• involved in the reaction that makes Ozone

10
Carbon Monoxide

• Invisible odorless gas results fron incomplete
  fuel combustion
• Another precursor to acid rain.
• Stunts plant growth

11
Ozone

• Produced when sunlight triggers reaction of
  natural atmosphere with pollutants
• Major Component of smog
• Causes Asthma and infection of the lungs
• Highly reactive with most rubber and Paint,
  harms most vegetation
• Not harmful in the stratosphere

12
Lead

• Reducing lead in the atmoshere is one of the
  great success stories of the EPA
• Most airborne lead was the result of lead in
  Gasoline.
• Lead was added to increase octane and decrease
  engine knocking
• decreased 98 from 1970 to 1993

13
Solutions

• Setting Ambient air standards
• Enforcing the policies set by the government
• providing techniques for emission reduction
• develop international agreements
• decrease non renewable energy consumption

14
Solutions

• Using mass transit
• Riding bicycle
• Hanging clothes out to dry
• turning off lights
• using solar power
• using recycled products

15
Acid deposition

• Begins with toxic air emissions
• sulfur dioxide into the air
• primarily from coal burning power plants
• pollutants react with sunlight and water vapor in
  the upper atmosphere
• Acidic compounds are formed (2 or more elements
  put together)

16
Acid deposition

• The compounds fall to earth in the form of rain
  or snow
• During the summer these acids may gather on dust
  and particulate matter and fall to the earth as
  dry acid deposition
• may fall hundreds of miles away from where it was
  formed

17
Measuring acidity

• Most commonly measured with a pH scale
• Ranges from 0-14
• a reading of 7 is neutral
• below 7 is acidic
• above 7 is basic
• a strong base is just as harmful as a strong acid

18
Measuring Acidity

• Scale is logarithmic therefore, there is a
  tenfold difference between one number and the
  number next to it.
• A drop from 6 to five is ten times stronger.
• A drop from six to four is 100 times stronger!
• Lemon juice (pH3) is 10,000 times stronger than
  distilled water which is pH7

19
Measuring Acidity

• Earths atmosphere is slightly acidic
• rain naturally has a pH of 5.6 or so
• Only rain that is more acidic than that is
  considered to be acid rain

20
Acid deposition Problems

• Extent of damage depends on total deposition in a
  certain area.
• Areas with acid neutralizing compounds in the
  soil can withstand years of bombardment.