At 1 1.2ppt Air Quality W&C Chapter 1.2 Pages 20-23

What is Air Pollution? Often noticeable as a brown haze or unpleasant smell Pollutants are 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 In the Ocean, water evaporates and leaves tiny salt particles in the air. Particles of mold and plant pollen blown by the wind. Forest Fires create smoke and ash.

Natural Causes Soil Erosion and Dust Storms add particles Volcanoes erupt, releasing massive amounts of dust, ash and poisonous gases high into the atmosphere.

Human Activities Most pollution is caused by human activities, like burning Fossil Fuels such as… Oil Gasoline Diesel Fuel Coal Burning Wood and Coal releases particles of carbon into the air, giving smoke its dark color.

Human Activities Farming activities and construction release large amounts of soil particles into the air Due to soil erosion An estimated 25% of CO2 pollution comes from cars/motor vehicles Roughly 50% comes from factories and power plants that burn coal & oil Coal & oil generate 45% of the electricity in the US.

Smog In 1905 smoke and fog combined and formed London-type smog. Smog occurs when water droplets combine with smoke (soot) in humid air No longer common in the US.

Photochemical “Smog” Photochemical smog forms a brown haze “Photo”= Light Caused by the reaction of sunlight on chemicals (nitrogen, oxides and hydrocarbons), producing a mix of ozone and other chemicals These chemicals cause rapid chemical weathering. LA and Mexico City

Exit Pass What are 3 major causes of pollution? Describe the difference between Smog and Photochemical Smog.

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

Temperature Inversion Temperature Inversion: a layer of warm air prevents the rising air from escaping Polluted air is trapped and held close to the surface, becoming concentrated and dangerous.

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 Affects living organisms, especially… marine life.

Acid Rain 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.

Improving Air Quality Many laws and regulations have been passed by the federal and state governments. Pollution Control Devices required on cars Power Plants must install 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 cause less pollution However, more cars are on the road and more power plants burning fossil fuels Air in cities is still polluted.

Effects of Air Pollution 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.

Exit Pass What is Temperature Inversion and why is it problematic?