Upload
virginia-smith
View
229
Download
0
Tags:
Embed Size (px)
Citation preview
POLLUTION
Air Pollution• Naturally occurring – dust, pollen, volcanic
eruptions• Human caused - Industrial burning,
automobile exhaust • Two types of air pollution:
– Primary: put directly into the atmosphere(ex: volcano, vehicles & coal burning)
– Secondary: forms in the atmosphere through chemical reactions(ex: ozone, smog)
Industrial Air Pollution
• Many industries and power plants burn fossil fuels to generate energy– (creates sulfur
dioxide, carbon dioxide, soot & carbon monoxide in atmosphere)
SmogDepends on:- local climate- Fuels used- Population density- Open fires
Natural Dilution
• Convection currents usually carry pollutants away from ground.
• Air close to ground is usually warmer than air at higher altitudes– less pressure at high
altitudes– less particles– therefore lower
temperature
Natural Dilution- When temperature inversions occur, pollution is
trapped near the surface- When air movement is low – disrupts convection
currents (at night, during a cold day, in a valley)- Cool air settles close to ground, warm air forms a
blanket above it
Thermal Inversions
Indoor Air Pollution Sources:industrial
chemicals,insulation,carpets,paint,
radon,carbon
monoxide,asbestosA “high risk
health problem”
Indoor Air Pollution
Can be reduced by:
- Modifying building codes to prevent radon
- Requiring exhaust hoods for applicances
- Set emissions standards for building materials
- Use office machinery in ventilated areas
Radon Gas
- Produced by decay of uranium found in
Earth’s crust.- Seeps through small openings in
buildings & sticks to dust particles
Radon Gas
• - Dust is inhaled by inhabitants & damages lung tissue
• - Many houses with basements have radon detectors
Asbestos• - Silicate mineral -
forms fibers that are heat-resistant, thin, strong, and flexible
• - Used for insulation and fire resistance in building materials
• - Found to be dangerous when inhaled and banned in 1970s
Asbestos
• - Exposure to asbestos particles cause severe damage to lung tissue
• - Causes difficulty breathing and possible heart failure
• - Rain, sleet, or snow containing a high concentration of acids due to air pollution
• - Sulfur dioxide and nitrogen oxides combine with water vapor
• to produce sulfuric acid and nitric acid- A regional problem
Acid Precipitation
• Flows into lakes, rivers, and streams.• Can kill/harm organisms
Acid Precipitation
- Normal precipitation is slightly acidic – carbon dioxide
forms carbonic acid
- Acid precipitation has pH of <5.6
- Typical rain in Eastern US is 4.6
Acid Precipitation
Acid Precip. Damage
- Causes a drop in pH of soil and water (acidification) that results in loss of soil nutrients & plant root damage
Acid Precip. Damage
- Can kill aquatic plants and animals.- Causes aluminum to leach out of soil
surrounding a lake. – accumulates in gills – fish suffocate
Acid Precip. Damage
- Acid shock - runoff of very acidic water into lakes and streams
- Decreases number of eggs produced at a time– many eggs do not hatch– birth defects common
Acid Precip. Damage
- Bodily harm to humans– Toxic metals released soil can be
absorbed by crops, water, and fish
- Economic impact– Decreases in numbers of fish– Damaged trees
- Aesthetic impact– harm to buildings
Acid Precip. Damage
Statue on a German castle built in 1702
Photograph from 1908 Photograph from 1968
Chlorofluorocarbons
• Nontoxic• Used in air conditioners, aerosol
spray cans, sterilants at hospitals and cleaners for computer chips.
• Take 10-20 years to reach stratosphere.
• Greatest contributor = air conditioners
Review…
• Carbon dioxide• Ozone• Layers of atmosphere
Who is affected?
• Infants• Elderly• People with heart and respiratory
disease• Pregnant women
Water Pollution
• Two main causes of water pollution:– 1. Industrialization – 2. Rapid human population growth
Water Pollution
• Comes from two types of sources: • 1. Point sources• 2. Nonpoint sources
Point-Source Pollution
• Comes from a specific site
Nonpoint-Source Pollution• Comes from multiple sources
Wastewater
- Contains wastes from homes or industry
- Wastewater treatment plants filter and treat water
Wastewater Treatment Process
Sewage Sludge
• - Byproduct of wastewater treatment • - Large volume of sludge is created each
year• - If toxic
– incinerated, and ash is buried in a secure landfill
• - Low toxicity– used as fertilizer– combined with clay to make bricks
Eutrophication
• Is accelerated when nutrients (P, N) enter water from fertilizer runoff, sewage, detergent.
Eutrophication
- Decreases dissolved O2 in water
- Due to build up of organic matter- Can convert body of water into
swamp or marsh.
Thermal Pollution
- Temperature increase in a body of water caused by human activity
- Result of industrial use
Thermal Pollution
- Decreased levels of oxygen- Death of aquatic organisms
(suffocation)- Destruction of entire habitat
Groundwater Pollution
- Common pollutants:PesticidesArtificial fertilizersLandfillsIndustrial wasteLeaking septic/waste tanks
Cleaning Up Groundwater Pollution- Big problem- Length of time to recycle ground
water- Pollution can remain after water is
recycled
Ocean Pollution
- DumpingWastewaterGarbage
- Most (85%) ocean pollution come from coastal land
- Coral reefs exist near coasts and are deeply impacted
Oil Spills
- Cause 5% of pollution in oceans - Mostly from cities and towns
Water Pollution in Ecosystems
• U.S. states limit amount of fish consumed from certain bodies of water
Water Pollution in Ecosystems
Biomagnification - accumulation of pollutants at successive levels of food chain.
Cleaning Up Water Pollution- The Clean Water Act (1972)
designed to restore and maintain clean water in US
- Goal: make surface water clean enough for fishing and swimming by 1983Missed goalResulted in stricter water-
quality standards nation-wide
Cleaning Up Water Pollution- Marine, Protection, Research, and
Sanctuaries Act (1972) Prevent ocean dumping
- Oil Pollution Act (1990) All oil tankers traveling in U.S. waters
must have double hulls by 2015