Urban Air Quality

1
Urban Air Quality
2
Urban Air Quality

• Gaseous Composition of the Atmosphere

3
Urban Air Quality

• Sources of Urban Air Pollutants
• Stationary Sources
• Mobile Sources
• Non-Point (Area)

4
Urban Air Quality

• Types of Urban Air Pollutants
• Primary Pollutant - a pollutant that directly
  enters the air as a result of natural events or
  human activities

5
Urban Air Quality

• Types of Urban Air Pollutants
• Examples of Primary Pollutants
• Carbon monoxide (CO)
• Carbon dioxide (CO2)
• Sulfur dioxide (SO2)
• Nitric oxide (NO)
• Hydrocarbons (HCs)
• Suspended Particulate Matter (SPMs)

6
Urban Air Quality

• Types of Urban Air Pollutants
• Secondary Pollutant - a pollutant that is formed
  in the air through chemical reactions between or
  among primary pollutants or between primary
  pollutants and other gases in the atmosphere

7
Urban Air Quality

• Types of Urban Air Pollutants
• Examples of Secondary Pollutants
• Nitrogen Dioxide (NO2)
• Sulfur Trioxide (SO3)
• Nitric Acid (HNO3)
• Hydrogen Peroxide (H2O2)
• Tropospheric Ozone (O3)
• Nitrate (NO3)
• Peroxyacetyl Nitrates (PANs)

8
Urban Air Quality

• Chemical Classes of Urban Air Pollutants
• Carbon Oxides
• CO
• CO2
• Sulfur Oxides
• SO
• SO2

9
Urban Air Quality

• Chemical Classes of Urban Air Pollutants
• Nitrogen Oxides
• NO (nitric oxide)
• NO2 (nitrogen dioxide)
• N2O (nitrous oxide - laughing gas!)
• Sulfur Oxides
• SO2 (sulfur dioxide)
• SO3 (sulfur trioxide)

10
Urban Air Quality

• Chemical Classes of Urban Air Pollutants
• Volatile Organic Compounds (VOCs)
• CH4 (methane)
• C6H6 (benzene)
• CFCs (chlorofluorohydrocarbons)
• CH20 (formaldehydr)

11
Urban Air Quality

• Chemical Classes of Urban Air Pollutants
• Suspended Particulate Matter (SPMs)
• Dust
• Soot
• Asbestos
• Pollen

12
Urban Air Quality

• Chemical Classes of Urban Air Pollutants
• Photochemical Oxidants
• O3 (tropospheric ozone)
• H2O2 (hydrogen peroxide)
• PANs (peroxyacetylnitrates)

13
Urban Air Quality

• Chemical Classes of Urban Air Pollutants
• Radioactive Substances
• Rn222 (Radon)
• Toxic Metals
• Pb - Lead
• Cd - Cadmium
• Hg - Mercury
• Ar - Arsenic

14
Urban Air Quality

• Regulation of Urban Air Pollution
• Clean Air Acts
• Passed in 1970, 1977, 1990
• Enacted federal air pollution regulations that
  are enforced by each state
• Established National Ambient Air Quality
  Standards (NAAQS)

15
Urban Air Quality

• Regulation of Urban Aair Pollution
• NAAQS
• 7 Criteria Pollutants
• SPMs
• Sulfur Oxides
• Carbon Monoxide
• Nitrogen Oxides
• Tropospheric Ozone
• VOCs
• Lead

16
Urban Air Quality

• Regulation of Urban Aair Pollution
• NAAQS
• Primary NAAQS - standards established to protect
  human health
• Secondary NAAQS - standards established to
  protect all organisms
• Nonattainment Area - any area that does not meet
  primary or secondary NAAQS for a criteria
  pollutant

17
Urban Air Quality

• National Ambient Air Quality Standards
• Carbon Monoxide 9 ppm over 8-hr period, not to
  be exceeded more than once a year 35-ppm
  for 1-hr period
• Ozone 0.12 ppm for 1-hr period, not to be
  exceeded more than once per year

18
Urban Air Quality

• National Ambient Air Quality Standards
• Sulfur Dioxide 0.03 ppm annual average 0.14
  ppm for 24-hr period, not to be exceeded
  more than once per year
• Nitrogen Oxides 0.05 ppm annual average

19
Urban Air Quality

• Regulation of Urban Air Pollution
• Criteria Pollutants
• Tropospheric Ozone
• Source Chemical reactions between VOCs, nitrogen
  oxides, and sunlight
• Health Effects Reduced lung function asthma
  congestion
• Environmental Impacts Reduced visibility plant
  damage, reduced photosynthesis and nutrient
  uptake, crop destruction forest diebacks
• Property Damage Rubber plastics

20
Urban Air Quality

• Regulation of Urban Air Pollution
• Criteria Pollutants
• Carbon Monoxide
• Source Incomplete combustion of fossil fuels
• Health Effects Reduced oxygen levels impaired
  visual perception reduced lung function asthma
  congestion
• Environmental Impacts Reduced visibility plant
  damage
• Property Damage Rubber plastics

21
Urban Air Quality

• Regulation of Urban Air Pollution
• Criteria Pollutants
• Nitrogen and Sulfur Oxides
• Source Incomplete combustion of fossil fuels
• Health Effects Lung damage respiratory
  illnesses
• Environmental Impacts Acid deposition plant
  damage photochemical smog crop destruction
• Property Damage Enhanced chemical weathering

22
Urban Air Quality

• Regulation of Urban Air Pollution
• Criteria Pollutants
• SPMs
• Source Incomplete combustion of fossil fuels
  agriculture unpaved roads
• Health Effects Lung damage respiratory
  illnesses
• Environmental Impacts Reduced visibility (haze
• Property Damage Discoloration of clothing and
  structures

23
Urban Air Quality

• Regulation of Urban Air Pollution
• Criteria Pollutants
• Lead
• Source Leaded gasoline lead paint smelters
  lead-acid batteries
• Health Effects Damage to nervous system cancer
  mental retardation digestive disorders
• Environmental Impacts Harmful to wildlife

24
Urban Air Quality

• Photochemical (Brown-Air) Smog
• A mixture of primary and secondary pollutants
  (mostly tropospheric ozone) formed under the
  influence of sunlight

25
Urban Air Quality

• Photochemical (Brown Air) Smog
• Factors of Formation
• Topography
• Local climate
• Population density
• Amount of industry
• Industrial fuel types

26
Urban Air Quality

• Photochemical (Brown Air) Smog
• Factors of Formation
• Topography
• Hills and mountains reduce air flow in valleys
  and allow pollutant levels to build up at ground
  level
• Buildings in cities slow wind speed, reducing
  dilution and dispersal of pollutants

27
Urban Air Quality

• Photochemical (Brown Air) Smog
• Factors of Formation
• Topography
• Thermal Inversion
• Sunny climate
• Light winds
• Mountains on three sides, ocean on the other
• High population density
• High motor vehicle usage
• High industrialization using fossil fuels

28
Urban Air Quality

• Photochemical (Brown Air) Smog
• Factors of Formation
• Topography
• Los Angeles Basin
• Hemmed in by mountains on 3 sides and ocean on
  the other
• 14 million people 23 million motor vehicles
• Frequent thermal inversions
• Air pollution capital of U.S.

29
Urban Air Quality

• Photochemical (Brown Air) Smog
• Factors of Formation
• Local Climate
• Areas with high average annual precipitation and
  wind speeds have less smog due to dilution and
  dispersal

30
Urban Air Quality

• Industrial (Gray-Air) Smog
• Mixture of sulfur dioxide, suspended droplets of
  sulfuric acid, and SPMs
• Found mostly in LDCs where coal and heavy oils
  are burned
• China
• Ukraine
• Eastern Europe

31
Urban Air Quality

• Acid Deposition
• The falling of acids and acid-forming compounds
  from the atmosphere to the Earths surface

32
Urban Air Quality

• Acid Deposition
• Components
• Primary Pollutants
• Nitrogen Oxides (NOx)
• Sulfur Oxides (SOx)
• Secondary Pollutants
• Nitric Acid (HNO3)
• Sulfuric Acid (H2SO4)

33
Urban Air Quality

• Acid Deposition
• Acid Sources
• Coal-burning power plants
• Smelters
• Factors
• Urban areas

34
Urban Air Quality

• Acid Deposition
• Mechanisms of Acid Deposition
• Dry Deposition
• Precipitation

35
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Regional environmental problem because acids
  remain in atmosphere for only a few days
• Environmental impacts depend on buffering
  capacity of soils

36
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Ecosystems most harmed by acid deposition are
  those with thin soils that lack natural buffering

37
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Damage to materials
• Statues
• Buildings
• Metals
• Car finishes

38
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Human Health
• Bronchitis
• Asthma

39
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Aquatic Ecosystems
• Acid Shock
• Aluminum toxicity
• Stimulates excessive mucus formation leading to
  asphyxiation of fish by clogging their gills

40
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Aquatic Ecosystems
• Formation of methylmercury
• Highly toxic
• Soluble in fatty tissue of animals
• Bioaccumulation

41
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Aquatic Ecosystems
• Fun Facts
• 16,000 lakes in Norway and Sweden contain no fish
• 9,000 lakes in U.S. are threatened with excess
  acidity (most in the Great Lakes!)

42
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Terrestrial Ecosystems
• Most damage when pH lt 5.1
• Damage to tree foliage bathed in acidic fog

43
Urban Air Quality

• Acid Deposition
• Environmental Impacts of Acid Deposition
• Terrestrial Ecosystems
• Increased susceptibility to various stressors
• Cold temperatures
• Diseases
• Insects
• Drought
• Depletion of plant nutrients

44
Urban Air Quality

• Urban Climate
• Cities are generally warmer, rainier, foggier,
  and cloudier than suburbs or rural areas

45
Urban Air Quality

• Urban Climate
• Cities generate enormous amounts of heat
• Automobiles
• Factories
• Furnaces
• Lights
• Air conditioners
• People

46
Urban Air Quality

• Urban Climate
• Urban Heat Island - the buildup of heat in the
  atmosphere above an urban area

47
Urban Air Quality

• Indoor Air Pollution
• Sources
• Combustion
• Building materials and furnishings
• Household cleaning products
• Personal care products
• Central heating/cooling systems
• Outside sources - radon gas and pesticides
• Poor ventilation

48
Urban Air Quality

• Indoor Air Pollution
• Most Dangerous Indoor Air Pollutants
• Formaldehyde
• Asbestos
• Cigarette smoke
• Radon-222
• Fiberglass

49
Urban Air Quality

• Indoor Air Pollution
• Leading cause of cancer
• High-risk health problem for humans
• Sick Building Syndrome
• Coughing
• Sneezing
• Nausea
• Burning eyes
• Flulike symptoms

50
Urban Air Quality

• Indoor Air Pollution
• Sick Building Syndrome
• 17 of all buildings in U.S. are sick,
  including the U.S. EPA headquarters in
  Washington, DC
• Mineral fibers falling from ceiling tiles are
  main culprit