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UNIT 7 – GLOBAL ATMOSPHERIC CHANGE
Learning Targets
Identify the major outdoor air pollution problems.
Describe the health effects of air pollution.
Describe how the earth’s climate is changing, causes, effects, and
solutions.
Sulfur dioxide (SO2): Colorless gas with irritating
odor; reacts with water vapor to create sulfuric
acid (H2SO4)
From natural sources in sulfur cycle, combustion of coal,
oil refining
Reduce visibility, breathing problems, aggravate
asthma; damage plant and animal life
Agenda
Notes
Video: Planet in Peril
Homework
Unit 7 Reading Assignment due Fri. Feb 19th
Unit 7 Current Event due Fri. Feb 19th
Particulates
Suspended Particulate Matter (SPM) is made of solid or
liquid particles that remain suspended in the air – lead,
soot, dust, asbestos, smoke
Sources: dust storms, wild fires, sea salt, plowing fields,
road construction, tobacco smoke, coal-burning electric
power plants
Most harmful are fine particles (PM-10) and ultrafine
particles ( PM-2.5)
Irritate respiratory system, asthma, bronchitis, reduce
visibility, corrode metals (toxics [lead, cadmium, PCBs]
can cause mutations, cancer)
Ozone (O3): colorless and highly reactive gas
Major component of photochemical smog
Coughing/breathing problems, irritate eyes/throat,
heart disease
Damage plants, rubber in tires, fabrics, and paints.
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Volatile Organic Compounds (VOCs)
Organic compounds that exist as gases in air
Most are hydrocarbons (isoprene and terpenes) emitted
by leaves of many plants and methane (comes from
plants, wetlands, termites, rice paddies, landfills, wells,
and cows)
Benzene, vinyl chloride are industrial solvents, drycleaning fluids, components of gasoline, drugs, rubber
Causes blood disorders, immune system damage,
dizziness, unconsciousness, death
AREAS IN THE U.S. FAIL AIR QUALITY
STANDARDS
Radon (Rn) – colorless and odorless radioactive
gas
Found in soil and rock
Seeps into homes and buildings sitting over the deposits
Can cause lung cancer with long-term exposure
Lead: particulate pollutant added to gas and used
in industrial metal smelting
Neurotoxin that is persistent and bioaccumulates
Children are most vulnerable
URBAN OUTDOOR POLLUTION
Industrial smog (gray
smog)
Carbon in coal and oil is
converted to CO and CO2,
unburned C ends up in air
as soot
Sulfur dioxide gas is turned
to sulfuric acid and
ammonium sulfate.
These suspended particles
are industrial smog
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URBAN OUTDOOR POLLUTION
Photochemical smog
(brown smog)
VOCs + NOx + heat +
sunlight ground level
ozone (photochemical
smog)
Sunny, warm, dry
climates with lots of cars
Irritates eyes, noses,
throats, damages plant
tissues
PHOTOCHEMICAL SMOG
FACTORS THAT INCREASE AIR POLLUTION
6-9am: People drive to work, NO and VOCs increase
1. Urban buildings, hills and valleys (slow wind
speed and reduce dilution and removal of
pollutants)
N2 + O2 → 2NO
NO + VOCs → NO2
NO2 +UV radiaCon → NO + O
9-11am: Traffic decreases, NO and VOCs react
2NO + O2 → 2NO2
11am-4pm: Sunlight intensifies, NO is broken down and
ozone increases
NO2 + UV radiaCon → NO + O
O2 + O → O3
2. Higher temperatures (photochemical smog)
3. Heat islands – metropolitan areas are
significantly warmer than their surroundings
4. Temperature inversions can cause buildup of
high levels of air pollution
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• Inversion layer: warm air mass traps cooler air
Air near surface cannot rise and mix with the air above it.
Pollutants can concentrate in this stagnant layer of cool air
near the ground.
Two major areas: valley surrounded by mountains or city
with mountains on 3 sides and ocean on other
FIGURE 18-11
HEALTH EFFECTS OF AIR POLLUTION
3.2 million deaths per year worldwide
Mostly in Asia; 1.2 million in China
150,000 to 350,000 in the United States
Air pollution can contribute to:
Asthma
Chronic bronchitis
Emphysema
Lung cancer
Heart attack
Stroke
PREMATURE DEATHS FROM AIR
POLLUTION IN THE U.S.
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AIR POLLUTION LEGISLATION
Air Pollution Act (1955)
First piece of legislation regarding air pollution
Identified air pollution as a national problem
Made the nation more aware of this
environmental hazard
AIR POLLUTION LEGISLATION
Clean Air Act
Designed to control air pollution at the national
level
Set standards for “The Six” criteria pollutants
(National Ambient Air Quality Standards):
Sulfur Dioxide (SO2), Particulates (PM), Lead (Pb),
Ozone (O3), Nitrogen Oxides (NOX) (Nitrous Oxide and
Nitrogen Oxide) and Carbon Monoxide (CO),
… Think SPLONC
Planet in Peril