Air Pollution Chapter 18

What Is the Nature of the Atmosphere? The atmosphere is structured in layers, including the troposphere, which supports life, and the stratosphere, which contains the protective ozone layer.

Troposphere – “Weather Breeder” - 75–80% of the earth’s air mass - Closet to the earth's surface - Chemical composition of air -Rising and falling air currents: weather and climate -Involved in chemical cycling

The Stratosphere Is Our Global Sunscreen Similar composition to the troposphere, with 2 exceptions Much less water O3, ozone layer, filters UV Location – 11 – 30 miles up

What is Air Pollution and What Are the Major Outdoor Pollution Problems? Air pollution – presence of chemicals in the atmosphere high enough to harm organisms, ecosystems or materials & to alter climate Natural sources Dust blown by wind Pollutants from wildfires and volcanoes Volatile organics released by plants Withdrawing groundwater Human (Anthropogenic) sources: mostly in industrialized and/or urban areas Stationary sources – examples include industry and power plants Mobile sources – examples include motor vehicles

Some Pollutants in the Atmosphere Combine to Form Other Pollutants Primary pollutants – released directly into atmosphere Secondary pollutants – formed by chemical reactions in air

What Are the Major Outdoor Air Pollutants? Carbon oxides Carbon monoxide (CO) Carbon dioxide (CO2) Sources - incomplete combustion of carbon-containing materials Human health and environmental impact CO reduces ability of blood to transport O2 CO2  Do you need to ask? ;-) Primary Pollutant

What Are the Major Outdoor Air Pollutants? Nitrogen oxides (NO) and nitric acid (HNO3) Sources – automobile engines & coal burning power plants Human health and environmental impact – greenhouse gas, acid deposition, irritation to eyes, nose, aggravated asthma, etc Photochemical smog (makes harmful O3) – more later Sulfur dioxide (SO2) and sulfuric acid (H2SO4) Sources – coal burning power plants & smelting Human health and environmental impact – acid deposition

What Are the Major Outdoor Air Pollutants? Particulates Suspended particulate matter (SPM) Sources – natural sources, plowed fields, construction, unpaved roads, tobacco smoke, coal burning power plants, cars Human health and environmental impact – Irritate nose, throat, aggravate asthma, some can accumulate in body (lead, PCB’s)

What Are the Major Outdoor Air Pollutants? Ozone (O3) Sources - photochemical smog Human and environmental impact – same as others, also damages plants, rubber in tires, etc. Volatile organic compounds (VOCs) Hydrocarbons, terpenes, methane Sources – natural sources, landfills, solvents, rice paddies, natural gas wells, etc. Human and environmental impact – greenhouse gas (CH4), damage plants, can cause cancer

Burning Coal Produces Industrial Smog Chemical composition of industrial smog (grey) Reduction of this smog in urban cities of the United States China and smog Human deaths

Sunlight Plus Cars Equals Photochemical Smog Chemical composition Sources VOCs + NO2 + Heat + Sunlight yields  Ground level O3 and other photochemical oxidants Aldehydes Other secondary pollutants Human health and environmental impact

A Model of How Pollutants That Make Up Photochemicals Are Formed

Several Factors Can Decrease or Increase Outdoor Air Pollution Outdoor air pollution may be decreased by Settling of particles due to gravity Rain and snow Salty sea spray from the ocean Winds Chemical reactions Outdoor air pollution may be increased by Urban buildings Hills and mountains High temperatures Emissions of VOCs from certain trees and plants Grasshopper effect Temperature inversions

A Temperature Inversion

What Is Acid Deposition and Why Is It a Problem? Acid deposition is caused mainly by coal-burning power plant and motor vehicle emissions, and in some regions, threatens human health, aquatic life and ecosystems, forests, and human-built structures.

Acid Disposition Is a Serious Regional Air Pollution Problem Acid deposition, acid rain Formation Local versus regional problems Effects of prevailing winds Buffers Where is the worst acid deposition?

Natural Capital Degradation: Acid Deposition, Acid Rain

Current and Possible Future Acid Rain Problem Areas

Acid Deposition Has a Number of Harmful Effects Human respiratory disorders Aquatic ecosystems affected Release of toxic metals Leaching of soil nutrients Loss of crops and trees Damage to buildings, statues, and monuments

Solutions: Acid Deposition, Prevention and Cleanup

What Are the Major Indoor Air Pollution Problems? The most threatening indoor air pollutants are smoke and soot from wood and coal cooking fires (a hazard found mostly in developing countries) and chemicals used in building materials and products. Developing countries Indoor burning Poor suffer the greatest risk Developed countries Indoor air pollution is greater than outdoor air pollution!!! WHY????

Indoor Air Pollution Is a Serious Problem You asked WHY????.... 11 of the common air pollutants higher inside than outside Greater in vehicles than outside Health risks magnified: people spend 70–98% of their time is indoors Who are at greatest risk from indoor air pollution? Children under 5 and the elderly Sick Pregnant women People with respiratory disorders or heart problems Smokers Factory workers

Indoor Air Pollution Is a Serious Problem Four most dangerous indoor air pollutants Tobacco smoke Formaldehyde Radioactive radon-222 gas Very small particles Sources of these pollutants Human health risks

Indoor Air Pollution Is a Serious Problem Other possible indoor air pollutants Pesticide residue Pb particles Living organisms and their excrements E.g., Dust mites and cockroach droppings Airborne spores of molds and mildews Sick-building syndrome – Let’s watch TWC - SICK BUILDINGS!

Science: Sources and Paths of Entry for Indoor Radon-222 Gas

What Are the Health Effects of Air Pollution? Air pollution can contribute to asthma, chronic bronchitis, emphysema, lung cancer, heart attack, and stroke.

Your Body’s Natural Defenses against Air Pollution Can Be Overwhelmed Respiratory system protection from air pollutants Role of cilia, mucus, sneezing, and coughing Effect of smoking and prolonged air pollution exposure Chronic bronchitis Emphysema

Normal Human Lungs and the Lungs of a Person Who Died of Emphysema

Air Pollution Is a Big Killer 3 Million deaths per year world-wide Mostly in Asia Main causes EPA: proposed stricter emission standards for diesel-powered vehicles Link between international trade and air pollution Cargo ships and pollution

Premature Deaths from Air Pollution in the U.S.

How Should We Deal with Air Pollution? Legal, economic, and technological tools can help to clean up air pollution, but much greater emphasis should be focused on preventing air pollution. - SOUND FAMILIAR???

Laws and Regulations Can Reduce Outdoor Air Pollution United States Clean Air Acts: 1970, 1977, and 1990 EPA National ambient air quality standards (NAAQs) for 6 outdoor criteria pollutants National emission standards for 188 hazardous air pollutants (HAPs) Toxic Release Inventory (TRI)

Laws and Regulations Can Reduce Outdoor Air Pollution Good news in U.S. Decrease in emissions Use of low-sulfur diesel fuel Cuts pollution Developing countries More air pollution

We Can Use the Marketplace to Reduce Outdoor Air Pollution Emission trading or cap-and-trade program Mixed reactions to program SO2 emissions down significantly NO2 will be tried in the future

Solutions: Stationary Source Air Pollution

Solutions: Motor Vehicle Air Pollution, Prevention and Cleanup

Solutions: Indoor Pollution, Prevention and Cleanup or Dilution