1. AIR POLLUTION PART I

2. Core Case Study: When Is a Lichen Like a Canary?
Lichens can warn us of bad air because they absorb it as a source of nourishment.
Figure 19-1

3. Core Case Study: When Is a Lichen Like a Canary?
Some lichen species are sensitive to specific air-polluting chemicals.
After Chernobyl, more than 70,000 reindeer had to be killed because they ate highly radioactive lichens.
Because lichens are widespread, long-lived, and anchored in place, they can help track pollution to its source.

4. STRUCTURE AND SCIENCE OF THE ATMOSPHERE
The atmosphere consists of several layers with different temperatures, pressures, and compositions.
Figure 19-2

5. Atmospheric pressure (millibars)
Temperature
Pressure
Thermosphere
Mesopause
Heating via ozone
Mesosphere
Altitude (kilometers)
Stratopause
Altitude (miles)
Stratosphere
Figure 19.2
Natural capital: the earth’s atmosphere is a dynamic system that consists of four layers. The average temperature of the atmosphere varies with altitude (red line). Most UV radiation from the sun is absorbed by ozone (O3), found primarily in the stratosphere in the ozone layer 17–26 kilometers (10–16 miles) above sea level. QUESTION: How did living organisms lead to the formation of the ozone layer?
Tropopause
Ozone “layer”
Heating from the earth
Troposphere
Pressure = 1,000 millibars at ground level
(Sea level)
Temperature (˚C)
Fig. 19-2, p. 440

6. STRUCTURE AND SCIENCE OF THE ATMOSPHERE
The atmosphere’s innermost layer (troposphere) is made up mostly of nitrogen (78%) and oxygen (21%), with smaller amounts of water vapor and CO2.
Ozone in the atmosphere’s second layer (stratosphere) filters out most of the sun’s UV radiation that is harmful to us and most other species. In the troposphere, ozone is a pollutant.

7. Primary vs Secondary Primary pollutants: enter atmosphere directly
Secondary pollutants: form due to chemical rxns occurring in air.

8. Primary & Secondary Pollutants

9. Primary Pollutants CO2 NOx - from fossil fuels anc volcanoes
SOx - from fossil fuels
PM10 – particulates with a diameter of 1/7 the size of human hair (<10 micrometers)
volatile organic compounds (VOCs)- compounds with a high vapor pressure ex. Toluene, xylene, formaldehyde, benzene, and acetone

10. Secondary Pollutants Examples:
Tropospheric Ozone – from sunlight, NOx and VOCs
acid rain- from sulfur dioxide and nitrogen dioxide
Peroxyacyl Nitrates (PANs)- from sunlight, NOx, and hydrocarbons

11. Case Study: Acid Rain Secondary Pollutant: Sulfuric Acid, H2SO4
SO2 + H2O  H2SO4
Burning coal
Reduces crop yields, irritates lungs

12. Effects of Air Pollution
Damages lungs and reduces visibility
Corrodes building materials
Contributes to global warming, acid rain, and ozone depletion
Bangkok

13. Causes most air pollution
Burning Fossil Fuels
Causes most air pollution

14. …By using alternative energy sources

15. -mix liquid w/ air pollutant  pollutant sinks w/ liquid.
Wet
Scrubber
-mix liquid w/ air pollutant  pollutant sinks w/ liquid.

16. Reduces emissions from combustion engines
Catalytic Converter
Reduces emissions from combustion engines
3 tasks:
A) take CO CO2
B) Take NOx O2 and N
C) Take HCs  CO2 and H2O

17. Smog
Smog
A mixture between smoke and fog that produces unhealthy urban air
Two Types
Photochemical Smog: NOx + Sunlight Ozone & NO
Sulfurous Smog: SO2 + Fog

18. Photochemical Smog (Brown Smog)
Photochemical smog is a mixture of primary and secondary pollutants formed under the influence of sunlight.
Primary Pollutants involved are mostly NOx and VOCs+ sunlight
Secondary Pollutants: ozone (O3), aldehydes (CH2O), PANS (peroxyacyl nitrates), and nitric acid (HNO3).

20. Sunlight plus Cars Equals Photochemical Smog

21. Industrial Smog (gray smog)
Industrial smog consists mostly of sulfur dioxide, suspended droplets of sulfuric acid, and a variety of suspended solid particles and droplets that emanate from coal and heavy oil burning power plants and factories.

22. Industrial Smog Chemistry
When coal and oil are burned:
C + O2 CO2 and/or 2C +O CO
The sulfur compounds in coal and oil react with oxygen to produce sulfur dioxide, a colorless, suffocating gas.
S + O SO2
In the troposphere, some of the sulfur dioxide reacts with oxygen to form sulfur trioxide which then reacts with water vapor to produce tiny suspended droplets of sulfuric acid.
2SO2 + O SO3
SO3 + H2O H2SO4
Some of the sulfuric acid droplets react with ammonia in the atmosphere to form solid particles of ammonium sulfate (salt). These salts + soot give the characteristic gray color to this smog.
2NH3 + H2SO (NH4)2SO4

23. Factors That Influence The Formation of Smog
Local climate
Topography
Amount of industry
Fuels used in industry, heating & transportation
Amount of precipitation (rain and snow cleanse atmosphere of pollutants)
Wind patterns (winds sweep pollutants away)
Hills and mountains reduce flow of air in valleys and allow pollutants to accumulate at ground level.
Diurnal temperature fluctuations allow pollutants to move upward and downward in atmosphere (density differences) to prevent pollutants from accumulating at ground level.

24. Other Highly Polluted Cities in the World
Mexico City
Denver, Colorado
Mexico City, Mexico
Rio de Janeiro and Sao Paulo, Brazil
Beijing and Shenyang, China
Bangkok, Thailand
Beijing,China

25. Human Respiratory System
Nasal Passage – hairs to filter out pollutants
Sneezing and coughing expel contaminated air.
Sticky mucus in upper respiratory track capture small particles and filter some gaseous pollutants.
Cells of upper respiratory tract are lines with cilia that move back and forth, transporting mucous and the pollutants they trap to your throat where they can be expelled.
Alveoli in bronchioles allow for proper gas exchange.

26. Effects of Air Pollution on Human Health
Elderly, infants, pregnant woman, and people with heart disease, asthma, or other respiratory diseases are most vulnerable to air pollution (indoor and outdoor).
lung cancer
asthma:
chronic bronchitis
emphysema

27. Effects of Air Pollutants on Health
Carbon monoxide (CO) – Binds hemoglobin more tightly than oxygen. From smoking, kerosene heaters, woodstoves, fireplaces, and faulty heating systems
Suspended Particulate Matter –cancer, asthma, lung disease
Sulfur dioxide – aggravates asthma
Nitrogen Oxides – especially NO2 can irritate the lungs, asthma, emphysema, malignant melanoma
VOC’s – (benzenes and formaldehyde) and toxic particulates such as lead, cadmium, PCB’s and dioxins (agent orange) can cause mutations, reproductive problems, and cancer.
Ozone – coughing, chest pain, shortness of breath, and eye, nose, and throat irritation.

28. How Many People Die Prematurely?
No one really knows.
Estimated annual deaths in USA related to outdoor air pollution = 65,000 – 200,000 mostly due to exposure to fine or ultra-fine particulate matter (after 9-11 will now start to see tremendous increases in those numbers in from NYC metropolitan region)
According to the American Lung Association air pollution in the USA costs a minimum of 150 billion dollars/year in health care costs and losses in work productivity.
WHO and World Bank estimated in 1997 that in China 2.7 million people die prematurely each year from the effects of outdoor air pollution.

29. Chloroflourocarbons (CFCs)
React with UV radiation to breakdown ozone in the ozone layer
CFCs were used in refrigerants, fire extinguishers, fumigation and agriculture
Montreal Protocol (1987) was designed to protect the stratospheric ozone layer. CFCs were to be phased out by 2000.

31. Solutions: Preventing and Reducing Air Pollutants
Clean Air Acts of 1970, 1977, and 1990 – These laws require the EPA to establish national ambient air quality standards (NAAQS) for seven criteriapollutants:
Suspended particulate matter
Sulfur oxides (SOx)
Carbon monoxide (CO)
Nitrogen oxides (NOx)
Ozone (O3)
Volatile Organic Compounds (VOC’s)
Lead (Pb)

32. “Prevention of Significant Deterioration”
National Emission Standards for Toxic Air Pollutants – includes 302 compounds and 20 categories of chemical compounds that are harmful to human health. (Due to lack of money provided to EPA, standards have only been set for a few of these compounds._
Car emissions tests – catalytic converters
Corporate Average Fuel Economy (CAFÉ) standards
Automotive gasoline must have 10% additive of ethanol or MTBE’s in many states
There have been decreases in atmospheric pollutants since the 1970’s of ground ozone, CO, SOx, suspended particulate matter, NO2 and lead (which has also decreased elsewhere  Cosmos “The Clean Room”, 18:20).

33. How Can US Air Pollution Laws Be Improved?
1. Pollution prevention is best! Leaded gasoline outlawed, lead in air was reduced by 98%.
2. Increase fuel efficiency standards for cars and trucks, this will reduce oil imports.
3. Require stricter emission standards.
4. Fund research and development of alternative energy resources.
Subsidize businesses and homeowners, vehicle owners for using energy conservation approaches such as hybrid vehicles, solar and wind energy for space heating, green buildings, etc..

34. What Can You Do? Car pool/mass transit. Turn off lights.
Buy technology endorsed by EPA’s Energy Stars Program.
Conserve water and electricity whenever possible
reduce, reuse, recycle
Walk, ride bike, roller blade, skateboard, motorcycle.