Air QualityAir QualityCH 15 Prentice Hall

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What is Air Pollution?

• A brown haze or unpleasant smell

• Pollutants= harmful substances in the air, water or soil.

Particles

• Air contains particles (pollutants) as well as gases.

• Come from both natural sources and human activities.

Natural Causes

• The Ocean- water evaporates and leaves tiny salt particles in the air.

• Particles of mold and plant pollen –blown by the wind.

• Forest Fires

Natural Causes

• Soil Erosion

• Dust Storms

• Volcanoes- erupt dust, ash and poisonous gases

• Most is caused by human activities– Burning Fossil Fuels

• Oil• Gasoline• Diesel Fuel• Coal

• Burning Wood and Coal – releases particles of carbon into the air.– These particles of soot give smoke its dark color.

Human Activities

• Farming activities and construction release large amounts of soil particles into the air.– Due to soil erosion.

• ½ of pollution comes from cars/motor vehicles.

• ¼ of pollution comes from factories and power plants that burn coal & oil.

Human Activities

Smog

• In 1905-smoke and fog combined and formed London-type smog. It occurs when water droplets combine with coal smoke (soot) in humid air.

• No longer common in the US.

Photochemical “Smog”• Photochemical smog forms a brown haze.– “Photo”= Light– Caused by the action of sunlight on chemicals

(nitrogen oxides and hydrocarbons), producing a mix of ozone and other chemicals.

• Los Angeles and Mexico City

• Normally warm air close to the surface is heated and rises carrying pollutants with it and are blown away.

Temperature Inversion

• During a temp inversion, A layer of warm air that prevents the rising air from escaping and polluted air is trapped and held close to the surface. It becomes concentrated and dangerous.

Temperature Inversion

• Forms when nitrogen oxides and other sulfur oxides combine with water in the air to form nitric acid and sulfuric acid.– Rain, sleet, snow, fog and even dry particles carry

these two acids.

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Acid Rain

• Rain is naturally acidic but rain that contains more than normal is classified as acid rain.

• Can damage the surface of buildings and statues.

• Can also effect living organisms.

Acid Rain

• Many laws and regulations have been passed by the federal and state governments.

• Pollution Control Devices required on cars

• Power Plants installed filters in smoke stacks to remove smoke.

Improving Air Quality

• Air quality has improved in the last 30 years.– Major air pollutants have decreased.– Newer cars are less polluting. (hybrid cars)– New power plants are less polluting.

• However, more cars are on the road and more power plants burning fossil fuels.

• Air in cities is still polluted.

Improving Air Quality

• Dizziness and headaches• Eye, nose, and throat irritation– Cough– Lung Disease

• Chest Pains• Allergies – Ragweed pollen causes “hay fever”

• Sneezing• Runny nose• Red itchy eyes.

Effects of Air Pollution