1. Chapter 9: Air: Climate and Pollution
The slide set includes information for Chapter Nine, ESRM100/ENVIR110, Environmental Science. Climate and Air Pollution.
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2. Chapter 9 Topics The Atmosphere and Climate Climate Change
Climate and Air Pollution
Interactions Between Climate Processes and Air Pollution
Effects of Air Pollution
Air Pollution Control
Clean Air Legislation
Current Conditions and Future Prospects
The following topics will be considered in this chapter, including the atmosphere and climate, climate change, climate and air pollution, interactions between climate and pollution, pollution effects, pollution control, clean-air laws, and current and future prospects for air pollution impacts on the environment.

3. Part 1: The Atmosphere and Climate
Understanding the composition of the Earth's atmosphere seems at first a pretty simple matter of analyzing the chemistry of that atmosphere. For instance, the main components of the lower atmosphere of the earth are: nitrogen at about 78%, oxygen had about 21%, argon at a little less than 1%, and a number of other gases in much smaller amounts. Carbon dioxide is an extremely important gas in the atmosphere even though its concentration is very low. In 2003 its actually about percent, as it has increased since this table was produced. All of the carbon assimilated by plants through the process of photosynthesis is taken directly from the atmosphere. The process of plant growth depletes this carbon dioxide, while the process of respiration restores that carbon dioxide to the atmosphere. The process of burning fossil fuels amends the content of carbon in the Earth's atmosphere. Most of the oxygen in the atmosphere has been produced as the result of the assimilation of carbon dioxide and the production of carbon in the Earth's strata in the form of carbonates, coal, oil and other C-containing materials.

4. The atmosphere has four distinct zones of contrasting temperature.
The atmosphere itself is composed of four distinctive zones divided by contrasting temperatures due to different amounts of absorption of solar energy. These zones include the troposphere which is the zone that humans live in, ranging from sea level to about 11 km, the stratosphere which ranges from about kilometers, the mesosphere which ranges from about km, and the thermosphere which ranges above 83 km in attitude. The pressure exerted by the atmosphere decreases very rapidly above sea level and is essentially zero at 20 to 30 kilometers above the earth's surface.

5. Energy and the "Greenhouse Effect"
Another extremely important aspect of the atmosphere is what is called the 'greenhouse effect". Of the energy that comes from the sun, and impacts on the top of the earth's atmosphere, only about half of the energy reaches the surface of the earth. The energy that is absorbed by the surface of the earth is changed to a lower quality heat energy, and most of that energy is re-emitted as infrared energy. Much of this energy is reflected back to the earth to be absorbed and re-emitted again, particularly when there is high cloud cover. Trapping of the energy with in the earth's atmosphere causes the earth to be warmer than it otherwise would be...like a greenhouse. Notice that the presence of cloud cover greatly changes the reflectivity and absorptivity of the earth, called the albedo. One of the major variables in the greenhouse effect is the presence of cloud cover.

6. Convection and Atmospheric Pressure
Evaporation
Latent heat
Condensation
Convection currents
Air pressure differences
Coriolis effect
The movement of the atmosphere of the earth has a reproducible general pattern caused by the spinning of the earth, and the heating and cooling at the cooler north and south poles relative to the warmer equator. These conditions produce movement of air around the earth through convection, the different zones of which are referred to as Hadley cells. Dominant winds, including the Westerlies and the Trade Winds, occur within these convection cells. These forces dictate to a large extent the movement and dispersal of pollutants and other substances through the atmosphere. Historically, trade that relied on air power could only occur well in the direction these winds and ocean currents dictated.

7. It is fortunate that these convection systems exist (fortunate for people living in polluted areas) because they act to distribute and disperse substances more widely on the earth than would otherwise occur. These movements of winds create pressure differentials that also distribute rain and weather more evenly throughout the earth than would otherwise occur.

8. Tornadoes are local cyclonic storms caused by rapid mixing of cold, dry air and warm, wet air.
Unfortunately, pressure differentials can create extremely powerful forces that are destructive in nature. For instance, tornadoes and cyclones are extremely powerful local winds generated by rapid mixing of cold, dry air and warm, wet air. They powerful forces can cause high levels of destruction including loss of life.

9. Hurricane Katrina will be the most costly disaster in US history, though the loss of life was not as high as some other disasters.

10. Seasonal Winds and Monsoons
The seasonality of weather is also a very important aspect of how weather influences the environment and people. For instance, in India, Society has depended on the timing and degree of monsoon rains that occur when warm, wet air from the Indian Ocean is drawn into the Indian subcontinent and releases rainfall as it rises and cools over the Himalayan mountains. Lack of monsoon rain due to different weather patterns sometimes causes drought, starvation, and death to people living in the region as well as to their animals, crops, and other organisms that depend on seasonal rainfall.

11. Part 2: Climate Change
The Earth's climate changes, often in short or long cycles.
Ice ages, droughts
Milankovitch cycles, orbital shifts, sunspot cycles, ocean currents
Climate does not necessarily change gradually - meteor impacts, methane releases?
Again in review, we define Climate as the general pattern of weather for a region over time. For instance, in Seattle in January we expect it to be cold and rainy. Weather is the short-time expression of climate which can vary significantly from day-to-day. Throughout the history of the Earth, climate has changed constantly on a long time scale. This is due partially to the movement of crustal plates and the interaction of weather with changing continent structure. Over the last 2 million years or so, the earth has experienced Ice Ages that occur on a relatively regular basis, along with smaller patterns of change in weather, like the mini-Ice-Ages that caused glaciers to advance on Mt. Rainier during the 1840's. Evidence of climate change is abundant in the Earth's record. It is thought that climate change normally follows long term cycles caused by shifts in the orbit of the earth, sunspot cycles, and possibly changes and ocean currents due to the movement of the continents. Certain catastrophic events such as a large asteroid or comet slamming into the earth could cause major climate change in a relatively short period of time. The possibility that a major impact such as this did in the dinosaurs about 65 million years ago is highly likely.

12. For instance, these figures show the variation in temperature during both the 400,000 years. Note that there were relatively large fluctuations in the average temperature of the earth including warmer periods and cooler periods than the present that lasted thousands of years. Note that large decreases and increases in temperatures are part of the climate record.

13. Milankovitch
cycles
Some of this variation is considered to to be due to Milankovitch cycles which occur because of changes in the Earth's orbit, a shifting of the tilt of the Earth's axis, and wobble that occurs along the Earth's axis. Of course, all of these changes would result substantial changes in the Earth's climate.

14. Some cycles have a particularly important impact on the Pacific Northwest. For instance, the El Niño/La Niña/Southern Oscillation cycle directly impacts trade winds that normally push warm water west toward Indonesia and allow the water to flow toward the coast of South America. Typically, El Niño results in warmer weather along the coast and significant climatic impacts such as increased rain and flooding in California. It causes warmer, drier weather in Oregon, Washington and British Columbia.

15. Human-Caused Global Climate Change
Global mean surface temperatures have increased about 0.9 degrees F over the past 100 years.
Much of this change is now understood to result from a number of human activities, primarily the burning of oil, gas, and coal.
CO2 levels are increasing 0.5% a year.
A major controversy regarding the atmosphere and climate is whether or not, and the degree to which human activity is changing climate. For instance, the surface temperatures of the earth have been increasing, although the high degree of variability of temperature may mask any changes and can make their measurements controversial. Many scientists believe that the burning of fossil fuels and emissions of carbon dioxide from land clearing have added to the greenhouse effect that we already know greatly increases relative temperatures of the Earth. For instance, it is a matter of simply measuring the levels of carbon dioxide in the atmosphere over time that carbon dioxide levels all are increasing at a rate of about 0.5% per year.

16. Carbon dioxide levels are increasing
This figure, for instance, shows the measurement of carbon dioxide at the Mauna Loa observatory in Hawaii. The amount of carbon dioxide has been increasing steadily. Note also the annual changes in carbon dioxide that give the curve a saw tooth appearance. These seasonal changes are due to the difference between respiration in the Spring and Summer in northern temperate areas, which has a much larger land surface area than the southern temperate areas. When Rob took Botany 101 at the University of Maryland in 1974, he was taught that carbon dioxide was 330 ppm, and it is now over 370 ppm on the average.

17. Increases in carbon dioxide are considered to be the major contributor to global warming potentially caused by human activity, accounting for nearly two-thirds of global warming. Methane, a much more potent but rarer component of the Earth's atmosphere, accounts for about 19%, with chlorofluorocarbons, nitrous oxides and Sulfur hexaflourides showing smaller relative impacts.

18. Possible Implications of and Debate Surrounding Global Warming
More heat waves
More extreme storm activity
Changes in rainfall, snowfall patterns
Ecosystem effects
Higher sea levels
More disease
Winners: Siberia, Scandinavia
Losers: most of U.S. (particularly SE; Washington may be nicer), island states
Skepticism
Kyoto Protocol
The potential impacts of global warming are numerous, and it is difficult to discount much of anything important. Depending on the location and current weather conditions, future climates could be hotter or cooler, show more or less precipitation, show more extreme storm activity, flooding of coastal areas, and potentially result in the increased spread and incidence of disease. One of the major impacts of climate change could be the migration or extinction of species not adapted to the future climate. In particular, where mountains range from east vs. west instead of north vs. south, extinctions are likely since the species dependent on previous conditions could not move north or south to adjust their environments.

19. Part 3: Climate and Air Pollution
Over the past 20 years, developed countries have made progress in improving air quality.
Unfortunately, air quality in the developing world has been getting worse.
It is certainly expected that human activities can affect the quality of air locally and regionally. Though the potential for significant man-caused global climate change remains somewhat controversial, most scientists agree that human activities can and potentially are having an impact on global air quality. The United States, in particular, has greatly increased air quality locally and regionally, and reduced air pollution, through enforcement of the Clean Air Act. Many countries have followed suit with programs for improving air quality as well. Unfortunately, in most cases, the less developed countries of the world have been unable to produce and enforce reasonable standards of air quality within their countries. Lower air pollution standards, in general, are one reason why companies that produce substantial amounts of pollution have sometimes moved their operations to less developed countries to save money.

20. Major Air Pollutants: Problems
Sulfur dioxide - acid rain, health damage, visibility reduction
Nitrogen oxides - acid rain, eutrophication, growth of weedy species
Carbon monoxide - inhibited respiration
Lead and mercury - neurological damage
Chlorofluorocarbons - ozone depletion
Particulate matter - lung damage, cancer
Volatile organic compounds - CO, CO2 production in the atmosphere
The following table shows major types of air pollutants. These include sulfur dioxide, which it is one of the most important components of acid rain, nitrous oxides, which add substantial nitrogen input into ecosystems, carbon monoxide, which adversely impacts human health, lead and mercury, which cause neurological damage in humans and potentially similar effects in animals, chlorofluorocarbons, which impact the ozone layer, particulates, which also impact human and animal health, and volatile organics, which have many different impacts on the Environment.

21. Indoor Air Pollution
Smoking - diseases related to smoking responsible for 20% of deaths in the U.S.
In less-developed countries, poorly ventilated heating and cooking fires represent the greatest source of indoor air pollution.
The United States has spent considerable money and effort to control outdoor air pollution. However, most Americans spend most of their day inside, and almost no effort has been made regulating the quality of air inside of buildings and homes. In many cases, sources of air pollution inside of homes, including chloroform, benzene, formaldehyde, and smoke are likely to be causing many more health problems that pollution outside of the home. One of the of major reasons that smoking has been banned in essentially every public building in Washington State is due to the adverse health impacts of the smoke within public buildings. Though this probably doesn't have much impact on the improvement of health of actual smokers, it probably eliminates the adverse impact on nonsmokers, which was substantial. When I lived in Tanzania, I cooked my meals on an open fire in many cases inside my hut. It's pretty obvious that I was constantly exposed to smoke, and smoke is known to have an adverse impact on human health. In countries where burning occurs inside of buildings without adequate ventilation smoke is almost certainly a serious health problem.

22. Part 4: Interactions Between Climate Processes and Air Pollution
Long-range transport
Stratospheric ozone depletion
Montreal Protocol
Temperature inversions
Heat islands, dust domes
Understanding how interactions between climate and air pollution occur is necessary to really understand the global impacts of air pollution. Global warming, where pollutants are actually altering the Earth's energy budget and thus its average climate, is a good example of the necessity to understand interactions of several factors. Major factors that would affect interactions include, long-range transport of pollutants, depletion of stratospheric ozone, efforts for and problems with the inaction of international protocols on emissions, and effects on urban environments such as temperature inversions, heat islands and urban dust domes.

23. The figure above shows the reduction in production of chlorofluorocarbons since the Helsinki convention, which largely banned their production, was passed in Notice that some developing countries continue to produce increasing levels of chlorofluorocarbons, though not nearly at the rate that the industrialized countries of the world produced 15 years ago.

24. Part 5: Effects of Air Pollution
Human health
Plant pathology
Visibility reduction
Acid deposition
Air pollution is likely just as serious for ecosystem health as it is for human health, though less is known about pollution impacts on ecosystems since much more money and effort is spent studying human health. Effects include impacts on plants, and thus impacts on all animals that require those plants and other animals as a source of food. The reduction of visibility in air is also a problem that is studied particularly because of the impact on human recreation. For instance, power plants have been proposed but not built in the four corners area of the American Southwest because of the potential impacts on visibility in the Grand Canyon. The Forest Service completed a study of the potential impacts of additional air pollution, such as from building or expanding emissions from power plants, on wilderness areas throughout the United States.

25. Ecosystem damage caused by sulfur dioxide emissions and acid rain.
Atmospheric deposition of pollutants is known to be a serious local and regional problem in some areas of the world. For instance, this picture shows the impact of sulfur dioxide emissions near Sudbury, Ontario, on local forests. Essentially all of the native vegetation has been destroyed, and soil has eroded down to bedrock in many areas. The installation of air pollution control equipment has greatly reduced emissions from the smelters recently, and many of the local ecosystems are beginning to recover.

26. Acid Precipitation, 2000
Less impressive but potentially far more destructive are regional and global impacts of air pollution, such as the impacts of acidic atmospheric deposition or "acid rain". For instance, acid rain greatly reduces the pH of precipitation in the United States Northeast because of the combustion of sulfur containing coal in the Midwestern United States. Sulfur dioxide from that combustion moves up into the atmosphere in is oxidized, creating sulfuric acid. Of course, everyone's heard the jingle "Sister Sally took a drink, but she shall drink no more, for what she thought was H20 was H2SO4". The pH of precipitation in the Pacific Northwest around Seattle is also slightly acidic, but this is due to the input of dimethyl-sulfide from upwelling ocean currents off the coast. This dimethyl-sulfide also oxidizes into sulfuric acid, and makes the precipitation more acid then water simply and collaborated with air, which has a pH of about In this case the acid rain is completely natural. The eruption of volcanoes can also create acidic precipitation naturally.

27. Typically, negative impacts on ecosystems are complicated and not necessarily due to one single factor. Negative impacts in the Appalachian Mountains of North Carolina, such as these at Mount Mitchell, are likely to be due to multiple impacts, that may be very difficult to understand completely. In the case of this Frazier fir stand, the Balsam Wooly adelgid, and insect similar to an aphid, actually killed the trees. However, it is likely that stresses such as those from atmospheric deposition in the region made the trees more susceptible to attack by the aphid. Many scientists have all argued about the reasons responsible for buybacks such as these on Mount Mitchell, but there is no resolution to the exact causes.

28. Here pollution can also negatively impact property
Here pollution can also negatively impact property. For instance, this statue, crafted in medieval times, has remained relatively intact for several hundred years. However, with the Industrial Revolution, and increasing acidity in the rainfall falling on the statue, the surface has eroded severely in the last few decades. Air pollution damage to buildings, roads, crops, and other properties amounts to billions of dollars loss per year. The loss of art such as the statue, is of course, priceless.

29. Part 6: Air Pollution Control
Early approach: "Dilution is the solution to pollution"
Particulate removal - air filters
Sulfur removal - scrubbers
Nitrogen oxide reduction - catalytic converters
Hydrocarbon controls - afterburners
There are several potential approaches toward solving problems of air pollution. For instance, an early approach was to dilute air pollution into the atmosphere, which seemed limitless. For the first cities, this was as effective as anywhere and moved pollution away from the city. However, as civilization created more and more cities, the pollution produced in one drifted into the other, causing problems for the downwind city. Thus, Society began to rely on systems that actually remove pollution before it was added to air. Among the first, very effective systems, were those that remove solid particles. Air filters, and electrostatic precipitators, could remove large amounts of potential air pollution and very small cost, and more among the first systems to be installed. Almost all industrial emissions into the air now include the removal of particles before discharge into the air. In the case of acid rain, adding sulfur removal to coal-fired power plants has been a priority. The United States, and other countries have already agreed to and begun to enforce limits on sulfur emissions. Thus, in the United States, the level of atmospheric deposition in the Northeast is already been reduced over what it was several decades ago. More difficult to impact, are emissions from automobiles. Nowadays, most automobiles are fitted with catalytic converters or other systems that reduce the production of of nitrous oxides. Other systems for air pollution control or constantly being created and existing systems improved.

30. Part 7: Clean Air Legislation
Clean Air Act of 1963
Clean Air Act of primary and secondary standards for ambient air quality
1990 update - significant amendments
Controversy
California - additional pollution control plans
The first examples of laws to improve air quality probably thousands of years old, including walls that prohibit burning inside of cities. In most cases, those laws were designed to reduce air pollution only in a small area, such as within a city. As populations increased and impacts became more serious, it was obvious that to work air pollution laws and needed to be regional, national, or global in scale. The Clean Air Act of 1963 was the first U.S. law aimed at improving air quality in the United States as a whole. This act provided incentives for states to reduce air pollution, but didn't require them to do so. The Clean Air Act of 1970 added many amendments that strengthened air pollution standards, and added primary and secondary standards for air quality. The 1990 update of the Clean Air Act added many more amendments, including controls on 188 airborne toxins from 250 types of sources. This amendment has been very controversial, with Congress often delaying implementation of its provisions, and states refusing to implement them. In the case of the state of California, which has experienced serious problems with negative impacts of air pollution, controls much stronger than federal standards have often been created and forced. Sometimes, California standards are used as models for other states.

31. Some Good News: U.S. Trends
For instance, figure 9.29 in the text shows reductions in carbon monoxide, volatile organic carbon, particulate matter, and sulfur dioxide since Notice, however, that nitrous oxide emissions have actually increased during that period of time because it is very difficult to adjust automobiles to reduce these emissions, and the number of automobiles and the actual miles driven has greatly increased during that period of time throughout the United States.

32. On the other hand, very little has changed in countries such as China, except for the expansion of industry, and large increases in air pollution. Add to that, coal is often burned within the home to cook food and heat homes, directly inside of Chinese cities. High sulfur Chinese coal leads to serious air pollution problems with in those cities. Much of what I remember of the cities of Shanghai, Xian, Chong-qing, in other smaller cities have visited was the smothering pollution within the city. The same is true of other countries that are rapidly industrializing, including within Mexico, Brazil, Jakarta, Bangkok, and many other cities. It remains to be seen whether wealth created by this industrialization will be partially channeled to improving air quality, as has been done in the United States, Europe, and Japan.