Air Pollution.

Air Pollution

The Atmosphere This is our protective blanket of gasses. 78% Nitrogen
21% Oxygen .03% Carbon Dioxide CO2 .01% Ozone 03

Atmospheric Gases

Atmospheric pressure (millibars)
Temperature Pressure Thermosphere Mesopause Heating via ozone Mesosphere Altitude (kilometers) Stratopause Altitude (miles) Stratosphere Figure 19.2 Natural capital: the earth’s atmosphere is a dynamic system that consists of four layers. The average temperature of the atmosphere varies with altitude (red line). Most UV radiation from the sun is absorbed by ozone (O3), found primarily in the stratosphere in the ozone layer 17–26 kilometers (10–16 miles) above sea level. QUESTION: How did living organisms lead to the formation of the ozone layer? Tropopause Ozone “layer” Heating from the earth Troposphere Pressure = 1,000 millibars at ground level (Sea level) Temperature (˚C) Fig. 19-2, p. 440

The Atmosphere - Layers
Troposphere Layer in which we live Most weather occurs here 90% of the gasses are here 78% nitrogen, 21% oxygen 0-6 mile above N and S Pole Mount Everest is 5.3 miles tall 0-10 miles above equator Temperature decreases with altitude until the next layer is reached Stratosphere 6-31 miles in altitude Calm Air traffic due to lack of weather Temperature increases with altitude Ozone layer (oxygen is converted to O3 by lightning and/or sunlight) 99% of ultraviolet radiation (especially UV-B) is absorbed by the stratosphere

Mesosphere 30 to 50 miles in altitude Temperature decreases with increasing altitude Temperatures in the mesopause (top of the mesosphere) are the coldest on Earth – approx. -100˚C (-148˚F) Above airplane heights and below orbital heights, thus it is poorly understood Thermosphere 50 to 310 miles in altitude Biggest of all layers Temperature increases with altitude Very high temperatures 1,500 °C (2,730 °F) to 2,500 °C (4,530 °F) but little heat is transferred because of the space between the gas particles International Space Station flies in this layer

Exosphere 310 miles to space Upper most layer of the atmosphere Only light elements exist here, mainly Hydrogen To the right is a scale representation of the atmospheric layers: Purple = Exosphere Blue = Thermosphere Green = Mesosphere Yellow = Stratosphere Red = Troposphere

Ozone How much of our atmosphere is ozone?
Ozone that surrounds the earth miles above the earth is our first line of defense of the sun’s ultraviolet radiation. This radiation can cause sunburn, skin cancer, cataracts, … Ozone is constantly created and destroyed

What Happens to Solar Energy Reaching the Earth?
Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds and supports plant growth. Figure 3-8

The Natural Greenhouse Effect
Three major factors shape the earth’s climate: The sun. Greenhouse effect that warms the earth’s lower troposphere and surface because of the presence of greenhouse gases. Oceans store CO2 and heat, evaporate and receive water, move stored heat to other parts of the world. Natural cooling process through water vapor in the troposphere (heat rises).

Greenhouse Effect This “greenhouse effect” is vital for our survival. Without heat trapping gasses our planet would be cold and lifeless. The gasses act like a car that gets hot inside.

Major Greenhouse Gases
The major greenhouse gases in the lower atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, ozone, and CFCs. These gases have always been present in the earth’s troposphere in varying concentrations. Fluctuations in these gases, plus changes in solar output are the major factors causing the changes in tropospheric temperature over the past 400,000 years. Gases are listed in order of abundance (greatest to least) Venus, Mars, and Titan also have greenhouse effects.

Major Greenhouse Gases
Increases in average concentrations of three greenhouse gases in the troposphere between 1860 and 2004, mostly due to fossil fuel burning, deforestation, and agriculture. Figure 20-5

PAST CLIMATE AND THE GREENHOUSE EFFECT
Over the past 900,000 years, the troposphere has experienced prolonged periods of global cooling and global warming. For the past 1,000 years, temperatures have remained fairly stable but began to rise during the last century.

PAST CLIMATE AND THE GREENHOUSE EFFECT
Figure 20-2

How Do We Know What Temperatures Were in the Past?
Scientists analyze tiny air bubbles trapped in ice cores learn about past: troposphere composition. temperature trends. greenhouse gas concentrations. Solar output, snowfall, and forest fire activity. Figure 20-3

How Do We Know What Temperatures Were in the Past?
In 2005, an ice core showed that CO2 levels in the troposphere are the highest they have been in 650,000 years. Figure 20-4

Greenhouse Effect If the gasses in the atmosphere become increased beyond “normal” the temperature of the earth can increase. An increase in temperature can change the climate cycles. Ice caps melt, drought, floods, change in temperature… Effects the environment as well What are some effects if the above happens?

Controversy CO2 levels are increasing due to human activity – no controversy What does that mean? - controversy 97% of climate scientists agree that this leads to global warming 53% of Americans believe global warming is real 87% of Europeans believe global warming is a serious concern

Data can be manipulated

From NOAA

EFFECTS OF GLOBAL WARMING
Between 1979 and 2005, average Arctic sea ice dropped 20% (as shown in blue hues above). Figure 20-8

Rising Sea Levels During this century rising seas levels are projected to flood low-lying urban areas, coastal estuaries, wetlands, coral reefs, and barrier islands and beaches. Figure 20-10

Rising Sea Levels If seas levels rise by 9-88cm during this century, most of the Maldives islands and their coral reefs will be flooded. Figure 20-11

Changing Ocean Currents
Global warming could alter ocean currents and cause both excessive warming and severe cooling. Figure 20-12

CLIMATE CHANGE AND HUMAN ACTIVITIES
Evidence that the earth’s troposphere is warming, mostly because of human actions: The 20th century was the hottest century in the past 1000 years. Since 1900, the earth’s average tropospheric temperature has risen 0.6 C°. Over the past 50 years, Arctic temperatures have risen almost twice as fast as those in the rest of the world. Glaciers and floating sea ice are melting and shrinking at increasing rates.

A warmer troposphere can decrease the ability of the ocean to remove and store CO2 by decreasing the nutrient supply for phytoplankton and increasing the acidity of ocean water. Global warming will lead to prolonged heat waves and droughts in some areas and prolonged heavy rains and increased flooding in other areas.

In a warmer world, agricultural productivity may increase in some areas and decrease in others. Crop and fish production in some areas could be reduced by rising sea levels that would flood river deltas. Global warming will increase deaths from: Heat and disruption of food supply. Spread of tropical diseases to temperate regions. Increase the number of environmental refugees.

DEALING WITH GLOBAL WARMING
Climate change is such a difficult problem to deal with because: The problem is global. The effects will last a long time. The problem is a long-term political issue. The harmful and beneficial impacts of climate change are not spread evenly. Many actions that might reduce the threat are controversial because they can impact economies and lifestyles.

Air Pollution Air Pollutant is defined as any substance in the air that is concentrated enough to harm living things or do damage to man-made objects. The EPA regulates (tries) pollution emissions from combustion by factories and machines.

Human Actions and Our Environment
When the human population was low, there was very little impact to the environment. Wind, rain, and time were the natural air cleaners. As the human population increased, time could not clean the air fast enough.

The human impact has changed three major ecosystem cycles. The chemical cycles Carbon Cycle Nitrogen Cycle Sulfur Cycle By adding more chemicals we slow down the cycle

2. The energy cycles Conservation of energy Energy from fossil fuels is used faster that replaced 3. Biodiversity is reduced Farms reduce the plant biodiversity with a single crop, and kill animals with chemicals

Air Pollution Primary pollutants – released directly into the atmosphere Ex) nitrogen oxides (NOx), sulfur oxides (SOx), methane (CH4), dust, Chlorofluorocarbons (CFCs) Causes of Primary Pollutants – factories, cars, wind and soil, volcanoes, forest fires, pollen, decaying plants, salt particles from the sea, and refrigerants.

Air Pollution Secondary pollutants – Form when primary pollutants react. Ex) ozone, smog, and acid rain

Air Pollutants – Carbon Oxides
Carbon monoxide (CO) is a highly toxic gas that forms during the incomplete combustion of carbon-containing materials. 93% of carbon dioxide (CO2) in the troposphere occurs as a result of the carbon cycle. 7% of CO2 in the troposphere occurs as a result of human activities (mostly burning fossil fuels). It is not regulated as a pollutant under the U.S. Clean Air Act.

CaCO3 in limestone Carbon in sugars, polysaccharides, and proteins Fossil fuels

Carbon Cycle The ocean is the largest carbon sink.
The process of CO2 being removed from the atmosphere and stored by a sink is called sequestration.

Ocean Acidification Dissolving CO2 in seawater increases the hydrogen ion (H+) concentration in the ocean, and thus decreases ocean pH. Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14, representing an increase of approaching 30% in acidity.

The Nitrogen Cycle:

Steps in Nitrogen Cycle
Nitrogen Fixation Lightning (N2  NO3) Bacteria (N2  NH4+) Nitrification (NH4+  NO2- (nitrite)  NO3-(nitrates)) Assimilation (NO3-(nitrates) converted to amino acids, DNA, chlorophyll) Ammoniafication (wastes and decaying organisms broken down into NH4+) Denitrification (nitrites are changed to N2 by anaerobic bacteria)

Air Pollutants – Nitrogen Oxides
The atmosphere is the largest nitrogen sink, storing nitrogen in the form of N2. NO2 reacts with water vapor in the air to form nitric acid (HNO3) and nitrate salts (NO3-) which are components of acid deposition.

Human Influence on Nitrogen Cycle
Fossil fuel combustion, Use of artificial nitrogen fertilizers, Release of nitrogen in wastewater At high temps, N2 reacts with O2 to form NOx. Gives brown color to smog Photochemical smog – nitrogen and light form “bad” ozone.

Air Pollutants – Sulfur Oxides
Naturally occurring Volcanoes Burning of coal, oil, gasoline Cause Lung damage, asthma, and bronchitis Sulfur can be removed from smoke by wet scrubbers in factories Largest sulfur sink is sedimentary rocks

Air Pollutants – Sulfur Oxides
Sulfur dioxide (SO2) and sulfuric acid: About one-third of SO2 in the troposphere occurs naturally through the sulfur cycle. Two-thirds come from human sources, mostly combustion (S+ O2  SO2) of sulfur-containing coal and from oil refining and smelting of sulfide ores. SO2 in the atmosphere can be converted to sulfuric acid (H2SO4) and sulfate salts (SO42-) that return to earth as a component of acid deposition.

The Sulfur Cycle Figure 3-32

Air Pollutants - VOCs Volatile organic compounds (VOCs):
Organic compounds (mostly hydrocarbons) that exist as gases in the air Ex) incomplete combustion of gasoline, methane About two thirds of global methane emissions comes from human sources. Can be natural (methane and terpenes) or man-made (trichlorethylene (TCE), benzene, CFCs and vinyl chloride). Long-term exposure to benzene can cause cancer, blood disorders, and immune system damage.

Air Pollutants - Ozone VOC + NOx + Sunlight = Ozone (O3) Ozone (O3):
It can Cause and aggravate respiratory illness. Can aggravate heart disease. Damage plants, rubber in tires, fabrics, and paints. Ozone (O3): “bad” ozone - found in troposphere Is a highly reactive gas that is a major component of photochemical smog.

Atmospheric Ozone Lightning and Ultraviolet light creates ozone, but there are a variety of things that can destroy it faster. THEY STAY AROUND LONGTERM CFC – Chlorofluorocarbons react with an oxygen atom to break down O3 to O2. 1 chlorine can destroy 100,000 ozone molecules CFC’s come from refrigeration and aerosol cans. As ozone is broken down, the ozone layer gets thinner. This radiation that gets through can cause sunburn, skin cancer, cataracts, …

Ultraviolet light hits a chlorofluorocarbon
(CFC) molecule, such as CFCl3, breaking off a chlorine atom and leaving CFCl2. Sun Cl Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. UV radiation A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2. The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2). Figure 20.18 Natural capital degradation: simplified summary of how chlorofluorocarbons (CFCs) and other chlorine-containing compounds can destroy ozone in the stratosphere faster than it is formed. Note that chlorine atoms are continuously regenerated as they react with ozone. Thus, they act as catalysts, chemicals that speed up chemical reactions without being used up by the reaction. Bromine atoms released from bromine-containing compounds that reach the stratosphere also destroy ozone by a similar mechanism. The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). Summary of Reactions CCl3F + UV Cl + CCl2F Cl + O3 ClO + O2 Cl + O Cl + O2 Repeated many times Fig , p. 486

Where is the ozone the thinnest?
Atmospheric Ozone Where is the ozone the thinnest?

New Index

Air Pollutants – Particulates
Suspended particulate matter (SPM): Consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air. Light enough to float in air Dust, lead, mercury, radon Get in lungs, stain buildings, reduce visibility

URBAN OUTDOOR AIR POLLUTION
Industrial smog is a mixture of sulfur dioxide, droplets of sulfuric acid, and a variety of suspended solid particles emitted mostly by burning coal. In most developed countries where coal and heavy oil is burned, industrial smog is not a problem due to reasonably good pollution control or with tall smokestacks that transfer the pollutant to rural areas.

Most suspended particles H2O2 O3 PANs
Primary Pollutants CO CO2 Secondary Pollutants SO2 NO NO2 Most hydrocarbons SO3 HNO3 H3SO4 Most suspended particles H2O2 O3 PANs Most NO3– and SO42– salts Sources Natural Stationary Figure 19.3 Natural capital degradation: sources and types of air pollutants. Human inputs of air pollutants may come from mobile sources (such as cars) and stationary sources (such as industrial and power plants). Some primary air pollutants may react with one another or with other chemicals in the air to form secondary air pollutants. Mobile Fig. 19-3, p. 442

ACID DEPOSITION Sulfur dioxides, nitrogen oxides, and particulates can react in the atmosphere to produce acidic chemicals that can travel long distances before returning to the earth’s surface. Tall smokestacks reduce local air pollution but can increase regional air pollution.

Acid Deposition AKA Acid Rain
Rain cleans the air, but pollutes the water. Normal pH is Acid Rain is about 4.3 Plants like to grown in soil with a pH of 6-7 What happens to the plants?

Lakes in deep soil high in limestone are buffered
ACID RAIN Wind Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas and particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts Wet acid depostion (droplets of H2SO4 and HNO3 dissolved in rain and snow) Nitric oxide (NO) Sulfur dioxide (SO2) and NO Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Acid fog Farm Lakes in shallow soil low in limestone become acidic Ocean Figure 19.6 Natural capital degradation: acid deposition, which consists of rain, snow, dust, or gas with a pH lower than 5.6, is commonly called acid rain. Soils and lakes vary in their ability to buffer or remove excess acidity. Lakes in deep soil high in limestone are buffered Fig. 19-6, p. 448

ACID DEPOSITION pH measurements in relation to major coal-burning and industrial plants. Figure 19-7

ACID DEPOSITION Air pollution is one of several interacting stresses that can damage, weaken, or kill trees and pollute surface and groundwater. Figure 19-9

Factors Influencing Levels of Outdoor Air Pollution
Outdoor air pollution can be reduced by: settling out, precipitation, sea spray, winds, and chemical reactions. Outdoor air pollution can be increased by: urban buildings (slow wind dispersal of pollutants), mountains (promote temperature inversions), and high temperatures (promote photochemical reactions).

Geography can effect pollution concentrations.

Topography and Pollution
Mountainous areas tend to trap pollution Flat areas tend to allow pollution to disperse

Forest Fires in the Los Angeles area.
Winds carry the smoke across the ocean. Wind can clean the air, but it can also spread it somewhere else.

Geography can effect air pollution.

Temperature Inversion
Cold air is more dense. Sometimes when it sinks below the warm air, it brings the pollution with it.

Temperature Inversions
Cold, cloudy weather in a valley surrounded by mountains can trap air pollutants (left). Areas with sunny climate, light winds, mountains on three sides and an ocean on the other (right) are susceptible to inversions. Figure 19-5

Rising smoke in Lochcarron, Scotland forms a ceiling over the valley due to a temperature inversion
Great Smog of 1952 – London – thousands died b/c of smog (respiratory illness)

Great Smog of 1952 London Thousands died b/c of smog (respiratory illness) Results: Caused evaluation of smog effects of health Passed the Clean Air Act of 1956 (UK)

How does air quality effect me?
Asthma Emphysema Allergies Heart disease Drink polluted water Colds Pneumonia

Law – Clean Air Act 1963 - first passage 1970, 1977 and 1990 - amended
Involves EPA Sets standards for acceptable levels of sulfur oxides, nitrogen oxides, ozone, carbon monoxide, hydrocarbons, lead, & cut out CFCs Provides pollution credits for industries that utilize pollution-control devices+ Bush administration relaxed rules

PREVENTING AND REDUCING AIR POLLUTION
The Clean Air Acts in the United States have greatly reduced outdoor air pollution from major pollutants: Carbon monoxide Nitrogen oxides Sulfur dioxides Suspended particulate matter

Deficiencies in the Clean Air Act: The U.S. continues to rely on cleanup rather than prevention. The U.S. Congress has failed to increase fuel-efficiency standards for automobiles. Regulation of emissions from motorcycles and two-cycle engines remains inadequate. There is little or no regulation of air pollution from oceangoing ships in American ports.

Airports are exempt from many air pollution regulations. The Act does not regulate the greenhouse gas CO2. The Act has failed to deal seriously with indoor air pollution. There is a need for better enforcement of the Clean Air Act.

National Ambient Air Quality Standards (NAAQS)
Sets acceptable concentrations for 6 “criteria” pollutants that: Threaten public health/the environment over broad areas (non-point) Are emitted in large quantities CO, Pb, Nitrogen Oxides, Ozone, Particulate Matter and Sulfur Dioxides

What kind of things are being done to control the pollution internationally?
Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change (UNFCCC), aimed at fighting global warming The United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty with the goal of achieving the "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.“

National Participation

Solutions: Reducing Outdoor Air Pollution
There are a of ways to prevent and control air pollution from motor vehicles. Because of the Clean Air Act, a new car today in the U.S. emits 75% less pollution than did pre-1970 cars. There is an increase in motor vehicle use in developing countries and many have no pollution control devices and burn leaded gasoline.

Solutions: Reducing Outdoor Air Pollution
There are a couple of ways to prevent and control air pollution from coal-burning facilities. Electrostatic precipitator: are used to attract negatively charged particles in a smokestack into a collector. Wet scrubber: fine mists of water vapor trap particulates and convert them to a sludge that is collected and disposed of usually in a landfill.

Electrostatic Precipitator
Can remove 99% of particulate matter Does not remove hazardous ultrafine particles. Produces toxic dust that must be safely disposed of. Uses large amounts of electricity Figure 19-18

Wet Scrubber Can remove 98% of SO2 and particulate matter.
Not very effective in removing hazardous fine and ultrafine particles. Figure 19-18

INDOOR AIR POLLUTION Indoor air pollution usually is a greater threat to human health than outdoor air pollution. According to the EPA, the four most dangerous indoor air pollutants in developed countries are: Tobacco smoke. Formaldehyde. Radioactive radon-222 gas. Very small fine and ultrafine particles.

Indoor Pollution Pollutant Where Found Health Effect Ammonia Arsenic
Asbestos Bacteria Benzene/Gasoline Carbon Monoxide Cleaning Products Smoking/pesticides/rodent poison Insulation Damp building Gasoline Wood burning fireplace, tobacco smoke, kerosene, automobiles, natural gas Respiratory Irritant Toxic / carcinogen Lung diseases Bacterial infections Respiratory irritant Headaches, drowsiness, dizziness, confusion, nausea, death

Chlorine treated water Tables, insulation, skateboards
Health Effect Pollutant Where Found Chloroform Fiberglass Formaldehyde Fungus/Mold Lead particulate Chlorine treated water Tables, insulation, skateboards Furniture stuffing, particle board, fiber board, foam insulation, carpeting Air systems, damp buildings Paint particulates, exhaust from leaded gasoline Cancer Respiratory and skin irritant Nasal/lung cancer, asthma, eye/nose/ throat irritant Respiratory irritant Impaired development, clumsiness, memory loss, anemia

Health Effect Pollutant Where Found Mercury Methane/Propane Tobacco Smoke Pesticides Fungicides, old thermometers/ thermostats Natural gas leaks / sewer backup Cigarettes, cigars, pipes Sprays, strips, outdoor air Damages nervous system, Cancer Headaches, fatigue, nausea, confusion, Cancer, heart disease, respiratory disease, ear infections Central nervous system/ Kidney / liver damage

Health Effect Pollutant Where Found Radon Trichloroethane VOCs Radioactive soil/foundations, Uranium deposits, radioactive well water Aerosol sprays Tobacco combustion, burned food, paints, varnishes, cleaning products Lung cancer, lung tissue damage Dizziness, irregular breathing Respiratory irritant, weakened immune system

Methods of prevention or clean-up
Improved Ventilation Tobacco smoke reduction methods Legislative measures Alternative materials Control temperature and humidity Alternative pest control Maintenance of appliances and filtering systems

Case Study: Radioactive Radon
Radon-222, a radioactive gas found in some soils and rocks, can seep into some houses and increase the risk of lung cancer. Sources and paths of entry for indoor radon-222 gas. Figure 19-13

Tobacco Smoke Carbon Monoxide Methylene Chloride
Para-dichlorobenzene Chloroform Tetrachloroethylene Formaldehyde 1, 1, 1- Trichloroethane Styrene Nitrogen Oxides Benzo-a-pyrene Particulates Tobacco Smoke Radon-222 Asbestos Carbon Monoxide Methylene Chloride Fig , p. 453

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