Air Pollution

Objectives Compare primary and secondary air pollutants Identify point-source and nonpoint-sources of air pollution in NC Identify sources of human-caused air pollution Describe how acid precipitation affects the environment

Air Pollution The contamination of the atmosphere. – Caused by the introduction of pollutants from human and natural sources

Direct Pollutants Direct pollutants are pollutants that are put directly in the air by human or natural activity

Human sources Carbon monoxide Particulate Matter including dust, lead, and asbestos fibers Smoke Fumes (for example chemicals from paint)

Natural Sources Sea salt Volcanic gases Ash and smoke from forest fires Pollen

Indirect Pollutants Pollutants that form when direct pollutants react with other direct pollutants or naturally occurring substances Examples: – Ozone (forms when sunlight reacts with vehicle exhaust and air) – Smog – Acid Rain

Action Ozone Days A warning to discourage outdoor activity by humans Why? – The ozone can damage lungs

Smog Step 1: Vehicle exhaust reacts with sunlight and air to form ozone Step 2: Ozone reacts with vehicle exhaust to form smog Ozone is a protective layer in the stratosphere, but near the Earth’s surface, it is a dangerous pollutant.

Haze Forms when emissions from power plants react with air

Human-caused Air Pollution Transportation – Cars = 10% - 20% – Vehicle exhaust forms smog and acid precipitation Industrial - burning fossil fuels and production of chemicals – Sources: chemical manufacturing plants, dry-cleaning businesses, furniture refinishers, and auto body shops

Indoor Air Pollution Sources – Chlorine and ammonia from household cleaners – Nitrogen oxides from unvented gas stoves, wood stoves or kerosene heaters – Fungi and bacteria from dirty heating and air conditioning ducts – Carbon monoxide from faulty furnace and car exhaust – Solvents from paint stripers and thinners – Gasoline from the car and lawn mowers – Formaldehyde from furniture, carpeting, particleboard, and foam insulation – Chemicals from dry cleaning

Reducing Indoor Air Pollution Ventilation – the mixing of indoor air and outdoor air Limit the use of chemical solvents and cleaners

Point Source Pollutants Pollutants that are released from a single source NC examples Smoke from burning brush Chemical wastes Gases from agricultural industries Particulate matter Underground oil or gas tanks that leak Landfills Industrial discharges Septic Systems Municipal wastewater discharge

Non-point Source Pollution Pollutants that come from many different sources (often difficult to identify) NC Examples: Pesticides Animal Waste Litter Trash and Raw Sewage Fertilizers Dumped Oil Pet Waste Acidic Deposition Sediment/Erosion Storm Water Runoff Grass Clipings/Sticks

Acid Precipitation Rain, sleet, or snow with a high concentration of acids that comes from air pollution When sulfur dioxide and nitrogen oxide combine with water, it forms sulfuric acid and nitric acid

Acidification When acid precipitation causes the acidity of the soil to increase.

Why is this a problem? When the acidity of the soil increases, some nutrients break down Plants needs the nutrients to grow, and there are fewer nutrients causing the plant to die and get washed away by the acid rain. Increased acidity also releases aluminum and other toxic metals that are absorbed by the roots of plants.

How does acid precipitation affect the aquatic ecosystem? Aquatic animals are used to a certain range of acidity. A rapid change in a body of water’s acidity is called acid shock.

Effects of Acid Shock Kills a large number of fish in a population at once Affects how fish absorb oxygen and nutrients making their eggs fragile.

Acid Precipitation Effects on Humans Increase in soil acidity can release toxic metals, such as aluminum and mercury into the soil. Can harm the respiratory health of children Toxic metal find their way into 4 main things: – Crops – Water – Fish – Human Body

Controlling Acid Precipitation is Complicated! WHY? – Pollutants are released in one area and may later fall to the ground as acid precipitation in an area hundreds of kilometers away. – Sometimes, pollution from one country results in acid precipitation in another country. Example – pollution produced in the US falls as over half of the acid precipitation in SE Canada

CANADA - U.S. AIR QUALITY AGREEMENT In 1991, the governments of Canada and the United States signed this agreement to reduce the acidic emissions that flowed across the US – Canadian borders. More of these agreements may be necessary to control acid precipitation

Brain Pop Air Pollution

Acid Rain Cause and Effect Flow Chart