class #13: friday, july 23 air pollution

Class #13 Friday, July 23, 2010 1

Class #13: Friday, July 23Air Pollution

Chapter 18


Air Pollution

Chapter 18


A Brief History of Air Pollution

• Air pollution not a new problem.• Smoke problems:– Caves– 1273 King Edward I– 1661 London– 1873 700 killed in London– 1911 smog killed 1150 Londoners


Types and Sources of Air Pollutants

• Primary and secondary• Fixed and mobile sources• Principal Pollutants– Particulates: PM-10, PM-2.5– Aerosols– Carbon Monoxide– Sulfur Dioxide (sulfuric acid)– VOCs (hydrocarbons)– Nitrogen dioxide, nitric oxide (nitric acid)

Class #13 Friday, July 23, 2010 5Fig. 18-CO, p. 500

Class #13 Friday, July 23, 2010 7Table 18-1, p. 503


Types and Sources of Air Pollutants Ozone in the Troposphere

Photochemical smog or oxidantsGround level ozoneSunlight dissociates which eventually causes oxygen to

combine and form ozoneBad ozone

Ozone in the StratosphereStratospheric ozone absorbs UV radiation; one reason

for increase in temperature in sphereGood ozone



• Ozone in the Stratosphere– Production-Destruction: ozone forms naturally

though combination of atomic oxygen with molecular oxygen, absorbs UV radiation and breaks down; creates balance

– Upsetting the Balance: anthropogenic chemicals nitrogen oxide and chlorofluorocarbons destroy ozone, disrupt balance and create ozone hole

Class #13 Friday, July 23, 2010 15Fig. 18-6, p. 507

Class #13 Friday, July 23, 2010 19Fig. 1, p. 511



• Air Pollution: Trends and Patterns– Clean Air Act 1970 has decreased air pollution in

the US, greatest reduction in lead (Unleaded gasoline)

– Increase in number of autos negates impact of Act is some areas

– Air quality index– Primary and Secondary National Ambient Air

Quality Standards

Class #13 Friday, July 23, 2010 23Stepped Art

Fig. 18-10, p. 512



• Environmental Issue: The Ozone Hole– The lowest concentration or ozone hole covers

most of Antarctica, but varies in coverage and intensity from year to year.

• Environmental Issue: Indoor Air Pollution– Indoor pollution can cause a variety of health

problems. Long-term exposure to some pollutants (radon, asbestos) can cause life-threatening diseases.


Factors that Affect Air Pollution

• The Role of Wind– Dilution of pollution dependent upon wind speed

• The Role of Stability and Inversions– Vertical mixing– Radiation inversion– Mixing layer– Mixing depth

Class #13 Friday, July 23, 2010 37Fig. 4a, p. 518

Class #13 Friday, July 23, 2010 38Fig. 4b, p. 518

Class #13 Friday, July 23, 2010 39Fig. 4c, p. 518

Class #13 Friday, July 23, 2010 40Fig. 4d, p. 518

Class #13 Friday, July 23, 2010 41Fig. 4e, p. 518



• Observation: Smoke stacks– Instability and wind impact pollution from smoke

stacks• Fanning• Fumigation• Looping• Coning• Lofting



• The Role of Topography– Mountains, valleys, and coasts and the orientation

to prevailing winds can exacerbate air pollution.– Denver, Los Angeles

Class #13 Friday, July 23, 2010 47Stepped Art

Fig. 18-18, p. 520



Severe Air PollutionIngredients○Many sources of pollution○ Stationary high pressure○ Light surface winds○ Subsidence inversion○ Shallow mixing layer○ Valley○ Clear night○ smog


Air Pollution and the Urban Environment

• Urban heat island• Country breeze• METROMEX


Acid Deposition

• Rain combines with sulfur dioxide and nitrogen oxides to create sulfuric and nitric acid

• Acidic deposition damages ecosystems, particularly lakes, and buildings

• Coal burning plants in Ohio Valley are source, greatest damage in Adirondacks

class #13: friday, july 23 air pollution

Documents

air pollution class

air pollutionchapter

sources of air pollutantsozone

primary air pollutants

ozone forms

ozone hole14class

thick layer of smoke

clear day