Human Impact on Air and Water Resources

Smog and Ozone

• Smog: a photochemical haze caused by solar radiation combining with chemicals in the air

• Ozone: a gas molecule made of three oxygen atoms– Very important in the upper atmosphere because

it blocks harmful UV radiation– It is an irritant at ground level and major part of

air pollution

Global Impacts of Air Pollution

1. Global Warming– The increase in Earth’s average surface

temperature• Partly caused by humans and the burning of fossil fuel• Scientists predict 3.5 degree rise in next 100 years

– This could cause changes in wind and rainfall patterns– Could affect agricultural areas, sea level rise, animals and

plant extinction if they can’t adjust to the changes

Global Impacts of Air Pollution

2. Ozone Depletion– CFC’s in the atmosphere caused a thinning and an

hole in the ozone layer over Antarctica3. Acid Precipitation– Forms when chemicals in the air combine with

rainfall– It can cause damage to aquatic ecosystems and

vegetation

Reducing Air Pollution

• 1990 Clean Air Act created higher standards for amounts of pollutants released into the air

• Coal-burning plants install scrubbers to reduce emissions

• Cleaner cars with higher emission testing

Water Pollution

• Point Sources– A single point of origin for water pollution such as

a factory, sewage, or toxic waste area• Nonpoint Sources– Pollution that comes from widely spread areas

such as rainwater which dissolves pesticides, poisons, etc

Water Pollution

• Pollution of Groundwater– Leaking chemical-storage barrels, sewage from

septic tanks can contaminate water flowing underground and be hard to access and clean

• Pollution in the Oceans– Sewage is a major source of pollution– Plastic is also an increasingly common pollution

found in oceans

Reducing Water Pollution

• The Safe Drinking Water Act of 1974– Designed to assure that everyone in the U.S. has

access to clean drinking water • The Clean Water Act 1972– Eliminate discharge of pollutants into rivers,

streams, etc and to restore water quality to levels that allow for recreational uses

– While there have been improvements, in 1998, 35% of US lakes and rivers were still in violation

Water Conservation

• Efficient irrigation can greatly reduce the demand for water

• Landscaping with plants that require less water

• Fixing leaky faucets and toilets

Assignment

• P.729 #1-4• P733 #1-4