Air Pollution

Overview o Atmosphere as a Resource o Types and Sources of Air Pollution Major Classes of Air Pollutants Major Classes of Air Pollutants Sources of Outdoor Air Pollutants Sources of Outdoor Air Pollutants Urban Air Pollution Urban Air Pollution o Effects of Air Pollution o Controlling Air Pollution in the US

Atmosphere as a Resource o Atmospheric Composition Nitrogen 78.08% Nitrogen 78.08% Oxygen 20.95% Oxygen 20.95% Argon 0.93% Argon 0.93% Carbon dioxide 0.04% Carbon dioxide 0.04% o Ecosystem services Blocks UV radiation Blocks UV radiation Moderates the climate Moderates the climate Redistributes water in the hydrologic cycle Redistributes water in the hydrologic cycle

Types and Sources of Air Pollution o Air Pollution Chemicals added to the atmosphere by natural events or human activities in high enough concentrations to be harmful Chemicals added to the atmosphere by natural events or human activities in high enough concentrations to be harmful o Two categories Primary Air Pollutant Primary Air Pollutant Harmful substance that is emitted directly into the atmosphere Harmful substance that is emitted directly into the atmosphere Secondary Air Pollutant Secondary Air Pollutant Harmful substance formed in the atmosphere when a primary air pollutant reacts with substances normally found in the atmosphere or with other air pollutants Harmful substance formed in the atmosphere when a primary air pollutant reacts with substances normally found in the atmosphere or with other air pollutants

Major Air Pollutants

Major Classes of Air Pollutants o Particulate Material o Nitrogen Oxides o Sulfur Oxides o Carbon Oxides o Hydrocarbons o Ozone

Particulate Material o Thousands of different solid or liquid particles suspended in air Includes: soil particles, soot, lead, asbestos, sea salt, and sulfuric acid droplets Includes: soil particles, soot, lead, asbestos, sea salt, and sulfuric acid droplets o Dangerous for 2 reasons May contain materials with toxic or carcinogenic effects May contain materials with toxic or carcinogenic effects Extremely small particles can become lodged in lungs Extremely small particles can become lodged in lungs

Nitrogen and Sulfur Oxides o Nitrogen Oxides Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at high temperature Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at high temperature Problems Problems Greenhouse gases Greenhouse gases Cause difficulty breathing Cause difficulty breathing o Sulfur Oxides Gases produced by the chemical interactions between sulfur and oxygen Gases produced by the chemical interactions between sulfur and oxygen Causes acid precipitation Causes acid precipitation

Carbon Oxides and Hydrocarbons o Carbon Oxides Gases carbon monoxide (CO) and carbon dioxide (CO 2 ) Gases carbon monoxide (CO) and carbon dioxide (CO 2 ) Greenhouse gases Greenhouse gases o Hydrocarbons Diverse group of organic compounds that contain only hydrogen and carbon (ex: CH 4 - methane) Diverse group of organic compounds that contain only hydrogen and carbon (ex: CH 4 - methane) Some are related to photochemical smog and greenhouse gases Some are related to photochemical smog and greenhouse gases

Ozone o Tropospheric Ozone Man- made pollutant in the lower atmosphere Man- made pollutant in the lower atmosphere Secondary air pollutant Secondary air pollutant Component of photochemical smog Component of photochemical smog o Stratospheric Ozone Essential component that screens out UV radiation in the upper atmosphere Essential component that screens out UV radiation in the upper atmosphere Man- made pollutants (ex: CFCs) can destroy it Man- made pollutants (ex: CFCs) can destroy it

Sources of Outdoor Air Pollution o Two main sources Transportation Transportation Industry Industry o Intentional forest fires is also high

Urban Air Pollution o Photochemical Smog (ex: Los Angeles below) Brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons Brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons

Formation of Photochemical Smog

Sources of Smog in Los Angeles

Case-In-Point Air Pollution in Beijing and Mexico City o Beijing (left) o Mexico City (above)

Controlling Air Pollution in US o Smokestacks with electrostatic precipitator (right) Without Electrostatic precipitator With Electrostatic precipitator

Controlling Air Pollution in the US o Smokestacks with scrubbers (right) o Particulate material can also be controlled by proper excavating techniques

Controlling Air Pollution in the US o Phase I Vapor Recovery System for gasoline

The Clean Air Act o Authorizes EPA to set limits on amount of specific air pollutants permitted o Focuses on 6 pollutants: lead, particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides, and ozone lead, particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides, and ozone o Act has led to decreases!

Other Ways to Improve Air Quality o Reduce sulfur content in gasoline from its current average of 330 ppm to 30 ppm Sulfur clogs catalytic converters Sulfur clogs catalytic converters o Require federal emission standards for all passenger vehicles Including SUVs, trucks and minivans Including SUVs, trucks and minivans o Require emission testing for all vehicles Including diesel Including diesel

Ozone Depletion in Stratosphere o Ozone Protects earth from UV radiation Part of the electromagnetic spectrum with wavelengths just shorter than visible light Part of the electromagnetic spectrum with wavelengths just shorter than visible light

Ozone Depletion in Stratosphere o Ozone thinning/hole First identified in 1985 over Antarctica First identified in 1985 over Antarctica o Caused by human-produced bromine and chlorine containing chemicals human-produced bromine and chlorine containing chemicals Ex: CFCs Ex: CFCs

Ozone Depletion in Stratosphere o Hole over Antarctica requires two conditions: Sunlight just returning to polar region Sunlight just returning to polar region Circumpolar vortex- a mass of cold air that circulates around the southern polar region Circumpolar vortex- a mass of cold air that circulates around the southern polar region Isolates it from the warmer air in the rest of the planet Isolates it from the warmer air in the rest of the planet o Polar stratospheric clouds form Enables Cl and Br to destroy ozone Enables Cl and Br to destroy ozone

Effects of Ozone Depletion o Higher levels of UV- radiation hitting the earth Eye cataracts Eye cataracts Skin cancer (right) Skin cancer (right) Weakened immunity Weakened immunity o May disrupt ecosystems o May damage crops and forests

Recovery of Ozone Layer o Montreal Protocol (1987) Reduction of CFCs Reduction of CFCs Started using HCFCs (greenhouse gas) Started using HCFCs (greenhouse gas) o Phase out of all ozone destroying chemicals is underway globally o Satellite pictures in 2000 indicated that ozone layer was recovering o Full recovery will not occur until 2050

Acid Deposition o Sulfur dioxide and nitrogen dioxide emissions react with water vapor in the atmosphere and form acids that return to the surface as either dry or wet deposition o pH scale

How Acid Deposition Develops

Effects of Acid Deposition o Declining Aquatic Animal Populations o Thin-shelled eggs prevent bird reproduction Because calcium is unavailable in acidic soil Because calcium is unavailable in acidic soil o Forest decline Ex: Black forest in Germany (50% is destroyed) Ex: Black forest in Germany (50% is destroyed)

Acid Deposition and Forest Decline

Air Pollution Around the World o Air quality is deteriorating rapidly in developing countries o Shenyang, China Residents only see sunlight a few weeks each year Residents only see sunlight a few weeks each year o Developing countries have older cars Still use leaded gasoline Still use leaded gasoline o 5 worst cities in world Beijing, China; Mexico City, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India Beijing, China; Mexico City, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India

Long Distance Transport of Air Pollutants

What Are the Health Effects of Air Pollution? What Are the Health Effects of Air Pollution? o 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 o Respiratory system protection from air pollutants Role of cilia, mucus, sneezing, and coughing Role of cilia, mucus, sneezing, and coughing o Effect of smoking and prolonged air pollution exposure Chronic bronchitis Chronic bronchitis Emphysema Emphysema

Major Components of the Human Respiratory System

Effects of Air Pollution o Low level exposure Irritates eyes Irritates eyes Causes inflammation of respiratory tract Causes inflammation of respiratory tract o Can develop into chronic respiratory diseases

Health Effects of Air Pollution o Sulfur Dioxide and Particulate material Irritate respiratory tract and impair ability of lungs to exchange gases Irritate respiratory tract and impair ability of lungs to exchange gases o Nitrogen Dioxides Causes airway restriction Causes airway restriction o Carbon monoxide Binds with iron in blood hemoglobin Binds with iron in blood hemoglobin Causes headache, fatigue, drowsiness, death Causes headache, fatigue, drowsiness, death o Ozone Causes burning eyes, coughing, and chest discomfort Causes burning eyes, coughing, and chest discomfort

Children and Air Pollution o Greater health threat to children than adults Air pollution can restrict lung development Air pollution can restrict lung development Children breath more often than adults Children breath more often than adults o Children who live in high ozone areas are more likely to develop asthma

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

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

Premature Deaths from Air Pollution in the U.S.

Indoor Air Pollution

What Are the Major Indoor Air Pollution Problems? o 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.

Indoor Air Pollution - Radon

Indoor Air Pollution o Pollutants can be 5-100X greater than outdoors o Most common: Radon, cigarette smoke, carbon monoxide, nitrogen dioxide, formaldehyde pesticides, lead, cleaning solvents, ozone, and asbestos Radon, cigarette smoke, carbon monoxide, nitrogen dioxide, formaldehyde pesticides, lead, cleaning solvents, ozone, and asbestos

Indoor Air Pollution Is a Serious Problem (1) o Developing countries Indoor burning Indoor burning Poor suffer the greatest risk Poor suffer the greatest risk o Developed countries Indoor air pollution is greater than outdoor air pollution Indoor air pollution is greater than outdoor air pollution

Indoor Air Pollution Is a Serious Problem (2) o Why? 11 of the common air pollutants higher inside than outside 11 of the common air pollutants higher inside than outside Greater in vehicles than outside Greater in vehicles than outside Health risks magnified: people spend 70–98% of their time is indoors Health risks magnified: people spend 70–98% of their time is indoors

Indoor Air Pollution Is a Serious Problem o Who are at greatest risk from indoor air pollution? Children under 5 and the elderly Children under 5 and the elderly Sick Sick Pregnant women Pregnant women People with respiratory disorders or heart problems People with respiratory disorders or heart problems Smokers Smokers Factory workers Factory workers

Indoor Air Pollution Is a Serious Problem (4) o Four most dangerous indoor air pollutants Tobacco smoke Tobacco smoke Formaldehyde Formaldehyde Radioactive radon-222 gas Radioactive radon-222 gas Very small particles Very small particles o Sources of these pollutants o Human health risks

Indoor Air Pollution Is a Serious Problem (5) o Other possible indoor air pollutants Pesticide residue Pesticide residue Pb particles Pb particles Living organisms and their excrements Living organisms and their excrements E.g., Dust mites and cockroach droppings E.g., Dust mites and cockroach droppings Airborne spores of molds and mildews Airborne spores of molds and mildews o Sick-building syndrome

Some Important Indoor Air Pollutants

Science: Magnified View of a Household Dust Mite in a Dust Ball

o o The U.S. Environmental Protection Agency (US EPA) and the Surgeon General's Office have estimated that as many as 20,000 lung cancer deaths are caused each year by radon. Radon is the second leading cause of lung cancer. Surgeon General's Office o o Modern houses tend to build up radon because the building envelope is almost airtight while the foundation is "leaky" to soil gas. The soil gas infiltration from basements ranges from less than 1% to over 20% of the total "fresh air" infiltration into homes (typically 3-5%). Opening basement windows to increase ventilation may help by removing the radon gas but it wastes energy and may actually draw in more soil gas. The best solution is sealing the concrete to ensure the foundation is more airtight than the building envelope. o o Radon gas accumulates in basements because of low ventilation. Heating and air-conditioning, natural air movement, the "stack effect," as well as diffusion of radon gas through the floors and walls distribute radon throughout the house. This, in turn, draws in more radon from the ground by concentration-driven diffusion until an equilibrium radon level is established on each floor in the house.

Fig , p. 485 Outlet vents for furnaces and dryers Open window Cracks in wall Openings around pipes Slab joints Wood stove Cracks in floor Sump pump Furnace Clothes dryer Slab Radon-222 gas Uranium-238 Soil