Urbanization and the Environment

1. Urbanization and the Environment Global Change II Dr. Vincent J. Abreu

2. "Urban Heat Islands."

3. What causes this to happen? • There are fewer trees, shrubs, and other plants to shade buildings, intercept solar radiation, and cool the air by "evapotranspiration." • Buildings and pavement made of dark materials absorb the sun's rays instead of reflecting them away, causing the temperature of the surfaces and the air around them to rise. • Surface roughness serves to reduce the wind speed and reduce ventilation.

4. Evapotranspiration • Evapotranspiration occurs when plants secrete or "transpire" water through pores in their leaves. • The water absorbs energy as it evaporates, cooling the air in the process. • A single mature, properly watered tree with a crown of 30 feet can "evapotranspire" up to 40 gallons of water in a day, which is like removing all the heat produced in four hours by a small electric space heater.

5. Heat Islands and Energy Use Higher temperatures in urban heat islands • greater demand for air conditioning • increased energy use • power plants burn more fossil fuels Increase both the pollution level and energy costs.

7. Photochemical Smog • Photochemical smog forms when oxides of nitrogen in motor vehicle exhaust and hydrocarbons (from various anthropogenic and biogenic sources) react in the presence of sunlight to produce a mixture of aerosols and gases (ozone (O3), formaldehyde (CH2O), ketones, and PAN (peroxyacetyl nitrates). • Average ozone level at the earth’s surface: 0.02 ppm • Ozone concentration may exceed 0.5 ppm in thick photochemical smog.

8. Urban heat islands and smog • Urban heat islands are smoggier. • Smog is created by photochemical reactions of pollutants in the air. These reactions are more likely to occur and intensify at higher temperatures. • In Los Angeles, for example, for every degree Fahrenheit the temperature rises above 70°F, the incidence of smog increases by 3%.

11. Urbanization and Water • Water is a key issue in urban areas. • The intensity of demand in cities can quickly exceed local supply. • The price of water is typically lower than the actual cost of obtaining, treating and distributing it, partly because of government subsidies.    • Pollution from urban run-off, sewage and untreated discharges of industries has adversely affected many water bodies, leaving many cities with unsafe water supply.

12. Urbanization and Water • Urbanization has had significant impacts on the hydrology of the environment by controlling: • Nature of runoff (water from precipitation or irrigation that does not evaporate or seep into the soil but flows into rivers, streams, or lakes, and may carry sediment); • Rates of soil erosion; and • Delivery of pollutants to rivers, streams, lakes and ocean.

15. Effect of urbanization on floods • Urbanization increases the intensity and decreases the lag time of floods. • Urbanization increases the frequency of small floods. • The size of small floods is increased by urbanization, while during large, infrequent floods there are no significant differences between the way rural and urban areas behave.

16. EROSION • Runoff on bare land leads to erosion. • Grass, trees and other plants hold the soil in place and avoid erosion. • The highest rates of erosion are produced in urban areas during construction. • Erosion is the source of sediment that fills streams, pollutes water, kills aquatic life, and shortens the useful life of dams and reservoirs.

17. Examples of Rates of Erosion associated with construction and urbanization

18. Water Pollution • Point source pollution • Industrial plant effluent pipe • Non-Point source pollution • Surface runoff from precipitation; responsible for most pollution. Pollution includes: Chemicals, sediments, heat, disease causing organisms

20. Water Pollutants • Suspended solids decrease in photosynthesis decrease in oxygen • Coliform Bacteria – if present in amounts greater than 200 colonies/ml of water, it is likely that other pathogens are present. • Chlorides – salt for de-icing • Phosphorus and nitrogen – plant nutrients

21. Biochemical Oxygen Demand Oxygen enters water by: Oxygen depletion by: Decomposition of organic material by bacteria Respiration of organisms O2 Dissolved in Water • Ocean Spray • Waves • Photosynthesis of • algae and large aquatic • plants Enhancement in Dissolved Nutrients (phosphorus and nitrogen) Cultural Eutrophication Algae growth Decomposition by bacteria Depletion of O2

23. Health Effects of Pollutants The relationship between water resources and health has occupied a position of special significance throughout human history. Sewage Industrial Pollutants Infectious Non-infectious Diseases Diseases- cancers, infertility thyroid dysfunction, birth defects, behavior problems, immune system suppression, deformities, etc.

25. Health Effects of Pollutants Synthetic chemicals in pesticides and industrial products have been identified as hormone disruptors Like hormones, these chemicals affect the endocrine systems of animals and humans in minute amounts – parts per trillion.

26. A vast number of man-made chemicals and chemical by-products have been identified as potential hazards. Some environmental groups and scientists have focused attention on: dioxins PCBs DDT and its metabolites Other Pesticides (including other organochlorines, and the triazines) alkylphenol ethoxylates PVC products bisphenol-A, phthalates pulp and paper production effluents spermicides and condom lubricants

27. Hormone Disruptors • Mimic naturally produced hormones such as estrogen and • testosterone. • Hormone blockers “lock up” a cell receptor”preventing • naturally produced hormones from entering and performing • their function. • Trigger set off reactions in the cell that would not normally • be produced by a hormone. Dioxin acts this way.

28. Hormone Disruptors • Mostly affects the offsprings of exposed organisms. • Health effects on humans include lower sperm counts, undescended testicles, early puberty, and thyroid dysfunction. • In wildlife, the health impacts include smaller penises, and/or testicle size, undescended testicles, lower sperm count, reproductive abnormalities, thyroid dysfunction, feminization of males or masculinization of females.

29. Where do we find them? • Endocrine-Disrupting Chemicals such as nonylphenol, alkylphenol ethoxylates (APEs) and phthalates are often found in common household items, such as detergents, cosmetics, household cleaners as well as even plastic food containers. • Several pesticides contain known or suspected endocrine disrupters that enter our bodies through residues on food. Heavy metals like lead, mercury and cadmium may be tracked in from outdoors.

30. Environmental Economics views the economy in which we live and work as an “open system”. Dispose of large amounts of dissipated and/or chemically transformed resources back into the environment. Process Resources Pollution Extract resources from the environment - renewable and exhaustible resources Resource Depletion

31. Why do we pollute? Pollution –waste that has been disposed off in the air, in water, or on land, and that reduces the value of those resources for alternative uses. In the case of air and water pollution, the damage is done because they are open access resources, i.e. no one owns them, and there is no individual incentive to restrict pollution.

32. Pollution reduction is an economic problem: How much money are we willing to spend to reduce pollution? • Ideal world – no pollution –costs would be very high • The other extreme is to live in a world with no pollution control • The real world is somewhere in between these two extremes, i.e., it is necessary to achieve a balance between the costs and social benefits of reducing pollution.

33. NO POLLUTION CONTROL Production of Goods Consumer Cost of Production Environmental Pollution Taxpayer Negative Externality Costs: Cleaning environment Health problems

34. Mechanisms to achieve pollution reduction Free market transactions are usually unregulated: there is no mechanism for charging polluters a fee to correct for the damage done by their emissions. Society decides on an acceptable level of environmental quality Government Intervention

35. Government Intervention:Subsidies based on Cost-Benefit Analysis Industrial Production Consumer Cost of Production Reduced Environmental Emissions • Government Intervention • Subsidies: • Tax Incentives • Credits • Regulations

36. What is the Clean Air Act? The Clean Air Act is the federal law designed to make sure that all Americans have air that is safe to breathe. • Main Goals: • Public health protection is the primary goal. • The law also seeks to protect our environment • from damage caused by air pollution.

37. When was the Clean Air Act passed? Congress passed the core provisions of the Clean Air Act in 1970. The law was amended in 1977 and again in 1990 to extend deadlines but also to specify new strategies for cleaning up the air. The basic framework of the law and its public health objective have remained intact.

38. How does the Clean Air Act work? • The Clean Air Act requires that: • The U.S. Environmental Protection Agency sets national health-based air quality standards to protect against common pollutants including ozone (smog), carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate soot. EPA is directed to review these standards every five years.  • State governments must devise cleanup plans to meet the health standards by a specific date. Areas with the worst smog have a longer time to meet the standards.

39. How does the Clean Air Act work? • In addition, the EPA sets national standards for major new sources of pollution including automobiles, trucks and electric power plants. • The agency also is charged with developing controls for major sources of toxic pollutants, such as benzene.

40. How well has the Clean Air Act worked? • By any objective measurement, the act has been a tremendous • success: • The air is cleaner and public health has improved. • Emissions of toxic lead have dropped 98 percent. • Emissions of sulfur dioxide have dropped by 35 percent • even though the gross domestic product has more than doubled. • Emissions of carbon monoxide have dropped by 32 percent even • though driving has increased 127 percent. • Even so, many areas of the country still violate the basic health • standards, and the health of tens of millions of Americans • remains at risk.

41. The Clean Water Act The Clean Water Act (CWA), intended to ". . .restore and maintain the chemical, physical, and biological integrity of the Nation's waters". To accomplish that objective, the act aimed to attain a level of water quality that "provides for the protection and propagation of fish, shellfish, and wildlife, and provides for recreation in and on the water" by 1983 and to eliminate the discharge of pollutants into navigable waters by 1985.

42. The CWA has five main elements: (1) A system of minimum national effluent standards for each industry. The CWA requires the EPA to establish effluent limitations for the amounts of specific pollutants that may be discharged by municipal sewage plants and industrial facilities. (2) Water quality standards. The two-step approach to setting the standards includes: (a) establishing a nationwide, base-level treatment through an assessment of what is technologically and economically achievable for a particular industry and (b) requiring more stringent levels of treatment for specific plants if necessary to achieve water quality objectives for the particular body of water into which that plant discharges.

43. (3) A discharge permit program that translates these standards into enforceable limits. Under the National Pollutant Discharge Elimination System program any person responsible for the discharge of a pollutant or pollutants into any waters of the United States from any point source must apply for and obtain a permit. (4) Provisions for special problems such as toxic chemicals and oil spills, and (5) A revolving construction loan program for publicly-owned treatment works.

44. Emission Control Policies Emission charges are prices established for the right to emit a unit of a pollutant. Emission standards are limits established by government on the annual amounts and kinds of pollutants that can be emitted into the air or water by producers or users of certain products. Command and control regulation: a system or rule that requires the use of specific pollution control devices on certain sources of pollution or applies strict emission standards to specific emitters.

45. Emission offsets allows a new firm to be established in an area where additional polluting emissions resulting from the firms operations normally would prevent the firm from being approved by EPA. Under this policy the new firm, before it is approved, most induce other firms in the area to reduce emissions usually through a cash payment. • The Bubble allows a firm to exceed the amount of emission of a pollutant if it reduces another pollutant by more than the current standard. • Banking of emissions: a firm that emits less than the specified level of a pollutant is given a credit that allows them to emit more than the standard at some time in the future. The firm is also allowed to sell these credits for cash to other firms who want to exceed the standards.

46. Pollution rights: a government-issued permit allowing a firm • to emit a specified quantity of polluting waste.Ex. Michigan’s • Air Emissions Trading Program. • Advantages: • Pollution permits are tradable at free market prices. • Regulatory authorities can control the amount of pollution by • limiting the number of certificates. • Provides a choice: purchase permits and pollute or reduce • pollution and save the cost of permits. • Provides an incentive to reduce emissions in order to sell • previously purchased pollution rights. • Disadvantages: • A firm in a very polluted region is allowed to buy emission • permits from a firm in a region where there is no pollution.

47. Failure of Government Intervention • They may favor the interests of some part of the community rather than the community as a whole. • Governments are not very good at obtaining the right information about the full consequences of a particular action. • They may have problems translating good intentions into practice because of lack of competence among the government bureaucracy.

48. Reducing pollution at the global level In some instances pollution is the result of activities at the global level and nations may be required to implement international agreements that address current pollution practices: • The Montreal Protocol • The Kyoto Protocol